LCOV - code coverage report
Current view: top level - src/backend/executor - functions.c (source / functions) Hit Total Coverage
Test: PostgreSQL 16beta1 Lines: 536 592 90.5 %
Date: 2023-06-06 08:12:15 Functions: 23 24 95.8 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * functions.c
       4             :  *    Execution of SQL-language functions
       5             :  *
       6             :  * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  *
      10             :  * IDENTIFICATION
      11             :  *    src/backend/executor/functions.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : #include "postgres.h"
      16             : 
      17             : #include "access/htup_details.h"
      18             : #include "access/xact.h"
      19             : #include "catalog/pg_proc.h"
      20             : #include "catalog/pg_type.h"
      21             : #include "executor/functions.h"
      22             : #include "funcapi.h"
      23             : #include "miscadmin.h"
      24             : #include "nodes/makefuncs.h"
      25             : #include "nodes/nodeFuncs.h"
      26             : #include "parser/parse_coerce.h"
      27             : #include "parser/parse_collate.h"
      28             : #include "parser/parse_func.h"
      29             : #include "rewrite/rewriteHandler.h"
      30             : #include "storage/proc.h"
      31             : #include "tcop/utility.h"
      32             : #include "utils/builtins.h"
      33             : #include "utils/datum.h"
      34             : #include "utils/lsyscache.h"
      35             : #include "utils/memutils.h"
      36             : #include "utils/snapmgr.h"
      37             : #include "utils/syscache.h"
      38             : 
      39             : 
      40             : /*
      41             :  * Specialized DestReceiver for collecting query output in a SQL function
      42             :  */
      43             : typedef struct
      44             : {
      45             :     DestReceiver pub;           /* publicly-known function pointers */
      46             :     Tuplestorestate *tstore;    /* where to put result tuples */
      47             :     MemoryContext cxt;          /* context containing tstore */
      48             :     JunkFilter *filter;         /* filter to convert tuple type */
      49             : } DR_sqlfunction;
      50             : 
      51             : /*
      52             :  * We have an execution_state record for each query in a function.  Each
      53             :  * record contains a plantree for its query.  If the query is currently in
      54             :  * F_EXEC_RUN state then there's a QueryDesc too.
      55             :  *
      56             :  * The "next" fields chain together all the execution_state records generated
      57             :  * from a single original parsetree.  (There will only be more than one in
      58             :  * case of rule expansion of the original parsetree.)
      59             :  */
      60             : typedef enum
      61             : {
      62             :     F_EXEC_START, F_EXEC_RUN, F_EXEC_DONE
      63             : } ExecStatus;
      64             : 
      65             : typedef struct execution_state
      66             : {
      67             :     struct execution_state *next;
      68             :     ExecStatus  status;
      69             :     bool        setsResult;     /* true if this query produces func's result */
      70             :     bool        lazyEval;       /* true if should fetch one row at a time */
      71             :     PlannedStmt *stmt;          /* plan for this query */
      72             :     QueryDesc  *qd;             /* null unless status == RUN */
      73             : } execution_state;
      74             : 
      75             : 
      76             : /*
      77             :  * An SQLFunctionCache record is built during the first call,
      78             :  * and linked to from the fn_extra field of the FmgrInfo struct.
      79             :  *
      80             :  * Note that currently this has only the lifespan of the calling query.
      81             :  * Someday we should rewrite this code to use plancache.c to save parse/plan
      82             :  * results for longer than that.
      83             :  *
      84             :  * Physically, though, the data has the lifespan of the FmgrInfo that's used
      85             :  * to call the function, and there are cases (particularly with indexes)
      86             :  * where the FmgrInfo might survive across transactions.  We cannot assume
      87             :  * that the parse/plan trees are good for longer than the (sub)transaction in
      88             :  * which parsing was done, so we must mark the record with the LXID/subxid of
      89             :  * its creation time, and regenerate everything if that's obsolete.  To avoid
      90             :  * memory leakage when we do have to regenerate things, all the data is kept
      91             :  * in a sub-context of the FmgrInfo's fn_mcxt.
      92             :  */
      93             : typedef struct
      94             : {
      95             :     char       *fname;          /* function name (for error msgs) */
      96             :     char       *src;            /* function body text (for error msgs) */
      97             : 
      98             :     SQLFunctionParseInfoPtr pinfo;  /* data for parser callback hooks */
      99             : 
     100             :     Oid         rettype;        /* actual return type */
     101             :     int16       typlen;         /* length of the return type */
     102             :     bool        typbyval;       /* true if return type is pass by value */
     103             :     bool        returnsSet;     /* true if returning multiple rows */
     104             :     bool        returnsTuple;   /* true if returning whole tuple result */
     105             :     bool        shutdown_reg;   /* true if registered shutdown callback */
     106             :     bool        readonly_func;  /* true to run in "read only" mode */
     107             :     bool        lazyEval;       /* true if using lazyEval for result query */
     108             : 
     109             :     ParamListInfo paramLI;      /* Param list representing current args */
     110             : 
     111             :     Tuplestorestate *tstore;    /* where we accumulate result tuples */
     112             : 
     113             :     JunkFilter *junkFilter;     /* will be NULL if function returns VOID */
     114             : 
     115             :     /*
     116             :      * func_state is a List of execution_state records, each of which is the
     117             :      * first for its original parsetree, with any additional records chained
     118             :      * to it via the "next" fields.  This sublist structure is needed to keep
     119             :      * track of where the original query boundaries are.
     120             :      */
     121             :     List       *func_state;
     122             : 
     123             :     MemoryContext fcontext;     /* memory context holding this struct and all
     124             :                                  * subsidiary data */
     125             : 
     126             :     LocalTransactionId lxid;    /* lxid in which cache was made */
     127             :     SubTransactionId subxid;    /* subxid in which cache was made */
     128             : } SQLFunctionCache;
     129             : 
     130             : typedef SQLFunctionCache *SQLFunctionCachePtr;
     131             : 
     132             : 
     133             : /* non-export function prototypes */
     134             : static Node *sql_fn_param_ref(ParseState *pstate, ParamRef *pref);
     135             : static Node *sql_fn_post_column_ref(ParseState *pstate,
     136             :                                     ColumnRef *cref, Node *var);
     137             : static Node *sql_fn_make_param(SQLFunctionParseInfoPtr pinfo,
     138             :                                int paramno, int location);
     139             : static Node *sql_fn_resolve_param_name(SQLFunctionParseInfoPtr pinfo,
     140             :                                        const char *paramname, int location);
     141             : static List *init_execution_state(List *queryTree_list,
     142             :                                   SQLFunctionCachePtr fcache,
     143             :                                   bool lazyEvalOK);
     144             : static void init_sql_fcache(FunctionCallInfo fcinfo, Oid collation, bool lazyEvalOK);
     145             : static void postquel_start(execution_state *es, SQLFunctionCachePtr fcache);
     146             : static bool postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache);
     147             : static void postquel_end(execution_state *es);
     148             : static void postquel_sub_params(SQLFunctionCachePtr fcache,
     149             :                                 FunctionCallInfo fcinfo);
     150             : static Datum postquel_get_single_result(TupleTableSlot *slot,
     151             :                                         FunctionCallInfo fcinfo,
     152             :                                         SQLFunctionCachePtr fcache,
     153             :                                         MemoryContext resultcontext);
     154             : static void sql_exec_error_callback(void *arg);
     155             : static void ShutdownSQLFunction(Datum arg);
     156             : static bool coerce_fn_result_column(TargetEntry *src_tle,
     157             :                                     Oid res_type, int32 res_typmod,
     158             :                                     bool tlist_is_modifiable,
     159             :                                     List **upper_tlist,
     160             :                                     bool *upper_tlist_nontrivial);
     161             : static void sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo);
     162             : static bool sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self);
     163             : static void sqlfunction_shutdown(DestReceiver *self);
     164             : static void sqlfunction_destroy(DestReceiver *self);
     165             : 
     166             : 
     167             : /*
     168             :  * Prepare the SQLFunctionParseInfo struct for parsing a SQL function body
     169             :  *
     170             :  * This includes resolving actual types of polymorphic arguments.
     171             :  *
     172             :  * call_expr can be passed as NULL, but then we will fail if there are any
     173             :  * polymorphic arguments.
     174             :  */
     175             : SQLFunctionParseInfoPtr
     176       31038 : prepare_sql_fn_parse_info(HeapTuple procedureTuple,
     177             :                           Node *call_expr,
     178             :                           Oid inputCollation)
     179             : {
     180             :     SQLFunctionParseInfoPtr pinfo;
     181       31038 :     Form_pg_proc procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
     182             :     int         nargs;
     183             : 
     184       31038 :     pinfo = (SQLFunctionParseInfoPtr) palloc0(sizeof(SQLFunctionParseInfo));
     185             : 
     186             :     /* Function's name (only) can be used to qualify argument names */
     187       31038 :     pinfo->fname = pstrdup(NameStr(procedureStruct->proname));
     188             : 
     189             :     /* Save the function's input collation */
     190       31038 :     pinfo->collation = inputCollation;
     191             : 
     192             :     /*
     193             :      * Copy input argument types from the pg_proc entry, then resolve any
     194             :      * polymorphic types.
     195             :      */
     196       31038 :     pinfo->nargs = nargs = procedureStruct->pronargs;
     197       31038 :     if (nargs > 0)
     198             :     {
     199             :         Oid        *argOidVect;
     200             :         int         argnum;
     201             : 
     202       10768 :         argOidVect = (Oid *) palloc(nargs * sizeof(Oid));
     203       10768 :         memcpy(argOidVect,
     204       10768 :                procedureStruct->proargtypes.values,
     205             :                nargs * sizeof(Oid));
     206             : 
     207       29838 :         for (argnum = 0; argnum < nargs; argnum++)
     208             :         {
     209       19070 :             Oid         argtype = argOidVect[argnum];
     210             : 
     211       19070 :             if (IsPolymorphicType(argtype))
     212             :             {
     213        2634 :                 argtype = get_call_expr_argtype(call_expr, argnum);
     214        2634 :                 if (argtype == InvalidOid)
     215           0 :                     ereport(ERROR,
     216             :                             (errcode(ERRCODE_DATATYPE_MISMATCH),
     217             :                              errmsg("could not determine actual type of argument declared %s",
     218             :                                     format_type_be(argOidVect[argnum]))));
     219        2634 :                 argOidVect[argnum] = argtype;
     220             :             }
     221             :         }
     222             : 
     223       10768 :         pinfo->argtypes = argOidVect;
     224             :     }
     225             : 
     226             :     /*
     227             :      * Collect names of arguments, too, if any
     228             :      */
     229       31038 :     if (nargs > 0)
     230             :     {
     231             :         Datum       proargnames;
     232             :         Datum       proargmodes;
     233             :         int         n_arg_names;
     234             :         bool        isNull;
     235             : 
     236       10768 :         proargnames = SysCacheGetAttr(PROCNAMEARGSNSP, procedureTuple,
     237             :                                       Anum_pg_proc_proargnames,
     238             :                                       &isNull);
     239       10768 :         if (isNull)
     240        6560 :             proargnames = PointerGetDatum(NULL);    /* just to be sure */
     241             : 
     242       10768 :         proargmodes = SysCacheGetAttr(PROCNAMEARGSNSP, procedureTuple,
     243             :                                       Anum_pg_proc_proargmodes,
     244             :                                       &isNull);
     245       10768 :         if (isNull)
     246        9932 :             proargmodes = PointerGetDatum(NULL);    /* just to be sure */
     247             : 
     248       10768 :         n_arg_names = get_func_input_arg_names(proargnames, proargmodes,
     249             :                                                &pinfo->argnames);
     250             : 
     251             :         /* Paranoia: ignore the result if too few array entries */
     252       10768 :         if (n_arg_names < nargs)
     253        6560 :             pinfo->argnames = NULL;
     254             :     }
     255             :     else
     256       20270 :         pinfo->argnames = NULL;
     257             : 
     258       31038 :     return pinfo;
     259             : }
     260             : 
     261             : /*
     262             :  * Parser setup hook for parsing a SQL function body.
     263             :  */
     264             : void
     265       63084 : sql_fn_parser_setup(struct ParseState *pstate, SQLFunctionParseInfoPtr pinfo)
     266             : {
     267       63084 :     pstate->p_pre_columnref_hook = NULL;
     268       63084 :     pstate->p_post_columnref_hook = sql_fn_post_column_ref;
     269       63084 :     pstate->p_paramref_hook = sql_fn_param_ref;
     270             :     /* no need to use p_coerce_param_hook */
     271       63084 :     pstate->p_ref_hook_state = (void *) pinfo;
     272       63084 : }
     273             : 
     274             : /*
     275             :  * sql_fn_post_column_ref       parser callback for ColumnRefs
     276             :  */
     277             : static Node *
     278       37676 : sql_fn_post_column_ref(ParseState *pstate, ColumnRef *cref, Node *var)
     279             : {
     280       37676 :     SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state;
     281             :     int         nnames;
     282             :     Node       *field1;
     283       37676 :     Node       *subfield = NULL;
     284             :     const char *name1;
     285       37676 :     const char *name2 = NULL;
     286             :     Node       *param;
     287             : 
     288             :     /*
     289             :      * Never override a table-column reference.  This corresponds to
     290             :      * considering the parameter names to appear in a scope outside the
     291             :      * individual SQL commands, which is what we want.
     292             :      */
     293       37676 :     if (var != NULL)
     294       35772 :         return NULL;
     295             : 
     296             :     /*----------
     297             :      * The allowed syntaxes are:
     298             :      *
     299             :      * A        A = parameter name
     300             :      * A.B      A = function name, B = parameter name
     301             :      *          OR: A = record-typed parameter name, B = field name
     302             :      *          (the first possibility takes precedence)
     303             :      * A.B.C    A = function name, B = record-typed parameter name,
     304             :      *          C = field name
     305             :      * A.*      Whole-row reference to composite parameter A.
     306             :      * A.B.*    Same, with A = function name, B = parameter name
     307             :      *
     308             :      * Here, it's sufficient to ignore the "*" in the last two cases --- the
     309             :      * main parser will take care of expanding the whole-row reference.
     310             :      *----------
     311             :      */
     312        1904 :     nnames = list_length(cref->fields);
     313             : 
     314        1904 :     if (nnames > 3)
     315           0 :         return NULL;
     316             : 
     317        1904 :     if (IsA(llast(cref->fields), A_Star))
     318          54 :         nnames--;
     319             : 
     320        1904 :     field1 = (Node *) linitial(cref->fields);
     321        1904 :     name1 = strVal(field1);
     322        1904 :     if (nnames > 1)
     323             :     {
     324         144 :         subfield = (Node *) lsecond(cref->fields);
     325         144 :         name2 = strVal(subfield);
     326             :     }
     327             : 
     328        1904 :     if (nnames == 3)
     329             :     {
     330             :         /*
     331             :          * Three-part name: if the first part doesn't match the function name,
     332             :          * we can fail immediately. Otherwise, look up the second part, and
     333             :          * take the third part to be a field reference.
     334             :          */
     335          24 :         if (strcmp(name1, pinfo->fname) != 0)
     336           0 :             return NULL;
     337             : 
     338          24 :         param = sql_fn_resolve_param_name(pinfo, name2, cref->location);
     339             : 
     340          24 :         subfield = (Node *) lthird(cref->fields);
     341             :         Assert(IsA(subfield, String));
     342             :     }
     343        1880 :     else if (nnames == 2 && strcmp(name1, pinfo->fname) == 0)
     344             :     {
     345             :         /*
     346             :          * Two-part name with first part matching function name: first see if
     347             :          * second part matches any parameter name.
     348             :          */
     349          24 :         param = sql_fn_resolve_param_name(pinfo, name2, cref->location);
     350             : 
     351          24 :         if (param)
     352             :         {
     353             :             /* Yes, so this is a parameter reference, no subfield */
     354          24 :             subfield = NULL;
     355             :         }
     356             :         else
     357             :         {
     358             :             /* No, so try to match as parameter name and subfield */
     359           0 :             param = sql_fn_resolve_param_name(pinfo, name1, cref->location);
     360             :         }
     361             :     }
     362             :     else
     363             :     {
     364             :         /* Single name, or parameter name followed by subfield */
     365        1856 :         param = sql_fn_resolve_param_name(pinfo, name1, cref->location);
     366             :     }
     367             : 
     368        1904 :     if (!param)
     369           0 :         return NULL;            /* No match */
     370             : 
     371        1904 :     if (subfield)
     372             :     {
     373             :         /*
     374             :          * Must be a reference to a field of a composite parameter; otherwise
     375             :          * ParseFuncOrColumn will return NULL, and we'll fail back at the
     376             :          * caller.
     377             :          */
     378         120 :         param = ParseFuncOrColumn(pstate,
     379         120 :                                   list_make1(subfield),
     380         120 :                                   list_make1(param),
     381             :                                   pstate->p_last_srf,
     382             :                                   NULL,
     383             :                                   false,
     384             :                                   cref->location);
     385             :     }
     386             : 
     387        1904 :     return param;
     388             : }
     389             : 
     390             : /*
     391             :  * sql_fn_param_ref     parser callback for ParamRefs ($n symbols)
     392             :  */
     393             : static Node *
     394      108896 : sql_fn_param_ref(ParseState *pstate, ParamRef *pref)
     395             : {
     396      108896 :     SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state;
     397      108896 :     int         paramno = pref->number;
     398             : 
     399             :     /* Check parameter number is valid */
     400      108896 :     if (paramno <= 0 || paramno > pinfo->nargs)
     401           6 :         return NULL;            /* unknown parameter number */
     402             : 
     403      108890 :     return sql_fn_make_param(pinfo, paramno, pref->location);
     404             : }
     405             : 
     406             : /*
     407             :  * sql_fn_make_param        construct a Param node for the given paramno
     408             :  */
     409             : static Node *
     410      110794 : sql_fn_make_param(SQLFunctionParseInfoPtr pinfo,
     411             :                   int paramno, int location)
     412             : {
     413             :     Param      *param;
     414             : 
     415      110794 :     param = makeNode(Param);
     416      110794 :     param->paramkind = PARAM_EXTERN;
     417      110794 :     param->paramid = paramno;
     418      110794 :     param->paramtype = pinfo->argtypes[paramno - 1];
     419      110794 :     param->paramtypmod = -1;
     420      110794 :     param->paramcollid = get_typcollation(param->paramtype);
     421      110794 :     param->location = location;
     422             : 
     423             :     /*
     424             :      * If we have a function input collation, allow it to override the
     425             :      * type-derived collation for parameter symbols.  (XXX perhaps this should
     426             :      * not happen if the type collation is not default?)
     427             :      */
     428      110794 :     if (OidIsValid(pinfo->collation) && OidIsValid(param->paramcollid))
     429        2666 :         param->paramcollid = pinfo->collation;
     430             : 
     431      110794 :     return (Node *) param;
     432             : }
     433             : 
     434             : /*
     435             :  * Search for a function parameter of the given name; if there is one,
     436             :  * construct and return a Param node for it.  If not, return NULL.
     437             :  * Helper function for sql_fn_post_column_ref.
     438             :  */
     439             : static Node *
     440        1904 : sql_fn_resolve_param_name(SQLFunctionParseInfoPtr pinfo,
     441             :                           const char *paramname, int location)
     442             : {
     443             :     int         i;
     444             : 
     445        1904 :     if (pinfo->argnames == NULL)
     446           0 :         return NULL;
     447             : 
     448        2676 :     for (i = 0; i < pinfo->nargs; i++)
     449             :     {
     450        2676 :         if (pinfo->argnames[i] && strcmp(pinfo->argnames[i], paramname) == 0)
     451        1904 :             return sql_fn_make_param(pinfo, i + 1, location);
     452             :     }
     453             : 
     454           0 :     return NULL;
     455             : }
     456             : 
     457             : /*
     458             :  * Set up the per-query execution_state records for a SQL function.
     459             :  *
     460             :  * The input is a List of Lists of parsed and rewritten, but not planned,
     461             :  * querytrees.  The sublist structure denotes the original query boundaries.
     462             :  */
     463             : static List *
     464       18294 : init_execution_state(List *queryTree_list,
     465             :                      SQLFunctionCachePtr fcache,
     466             :                      bool lazyEvalOK)
     467             : {
     468       18294 :     List       *eslist = NIL;
     469       18294 :     execution_state *lasttages = NULL;
     470             :     ListCell   *lc1;
     471             : 
     472       36704 :     foreach(lc1, queryTree_list)
     473             :     {
     474       18416 :         List       *qtlist = lfirst_node(List, lc1);
     475       18416 :         execution_state *firstes = NULL;
     476       18416 :         execution_state *preves = NULL;
     477             :         ListCell   *lc2;
     478             : 
     479       36832 :         foreach(lc2, qtlist)
     480             :         {
     481       18422 :             Query      *queryTree = lfirst_node(Query, lc2);
     482             :             PlannedStmt *stmt;
     483             :             execution_state *newes;
     484             : 
     485             :             /* Plan the query if needed */
     486       18422 :             if (queryTree->commandType == CMD_UTILITY)
     487             :             {
     488             :                 /* Utility commands require no planning. */
     489         156 :                 stmt = makeNode(PlannedStmt);
     490         156 :                 stmt->commandType = CMD_UTILITY;
     491         156 :                 stmt->canSetTag = queryTree->canSetTag;
     492         156 :                 stmt->utilityStmt = queryTree->utilityStmt;
     493         156 :                 stmt->stmt_location = queryTree->stmt_location;
     494         156 :                 stmt->stmt_len = queryTree->stmt_len;
     495             :             }
     496             :             else
     497       18266 :                 stmt = pg_plan_query(queryTree,
     498       18266 :                                      fcache->src,
     499             :                                      CURSOR_OPT_PARALLEL_OK,
     500             :                                      NULL);
     501             : 
     502             :             /*
     503             :              * Precheck all commands for validity in a function.  This should
     504             :              * generally match the restrictions spi.c applies.
     505             :              */
     506       18416 :             if (stmt->commandType == CMD_UTILITY)
     507             :             {
     508         156 :                 if (IsA(stmt->utilityStmt, CopyStmt) &&
     509           0 :                     ((CopyStmt *) stmt->utilityStmt)->filename == NULL)
     510           0 :                     ereport(ERROR,
     511             :                             (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
     512             :                              errmsg("cannot COPY to/from client in an SQL function")));
     513             : 
     514         156 :                 if (IsA(stmt->utilityStmt, TransactionStmt))
     515           0 :                     ereport(ERROR,
     516             :                             (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
     517             :                     /* translator: %s is a SQL statement name */
     518             :                              errmsg("%s is not allowed in an SQL function",
     519             :                                     CreateCommandName(stmt->utilityStmt))));
     520             :             }
     521             : 
     522       18416 :             if (fcache->readonly_func && !CommandIsReadOnly(stmt))
     523           0 :                 ereport(ERROR,
     524             :                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
     525             :                 /* translator: %s is a SQL statement name */
     526             :                          errmsg("%s is not allowed in a non-volatile function",
     527             :                                 CreateCommandName((Node *) stmt))));
     528             : 
     529             :             /* OK, build the execution_state for this query */
     530       18416 :             newes = (execution_state *) palloc(sizeof(execution_state));
     531       18416 :             if (preves)
     532           6 :                 preves->next = newes;
     533             :             else
     534       18410 :                 firstes = newes;
     535             : 
     536       18416 :             newes->next = NULL;
     537       18416 :             newes->status = F_EXEC_START;
     538       18416 :             newes->setsResult = false;   /* might change below */
     539       18416 :             newes->lazyEval = false; /* might change below */
     540       18416 :             newes->stmt = stmt;
     541       18416 :             newes->qd = NULL;
     542             : 
     543       18416 :             if (queryTree->canSetTag)
     544       18410 :                 lasttages = newes;
     545             : 
     546       18416 :             preves = newes;
     547             :         }
     548             : 
     549       18410 :         eslist = lappend(eslist, firstes);
     550             :     }
     551             : 
     552             :     /*
     553             :      * Mark the last canSetTag query as delivering the function result; then,
     554             :      * if it is a plain SELECT, mark it for lazy evaluation. If it's not a
     555             :      * SELECT we must always run it to completion.
     556             :      *
     557             :      * Note: at some point we might add additional criteria for whether to use
     558             :      * lazy eval.  However, we should prefer to use it whenever the function
     559             :      * doesn't return set, since fetching more than one row is useless in that
     560             :      * case.
     561             :      *
     562             :      * Note: don't set setsResult if the function returns VOID, as evidenced
     563             :      * by not having made a junkfilter.  This ensures we'll throw away any
     564             :      * output from the last statement in such a function.
     565             :      */
     566       18288 :     if (lasttages && fcache->junkFilter)
     567             :     {
     568       18004 :         lasttages->setsResult = true;
     569       18004 :         if (lazyEvalOK &&
     570       17362 :             lasttages->stmt->commandType == CMD_SELECT &&
     571       17302 :             !lasttages->stmt->hasModifyingCTE)
     572       17302 :             fcache->lazyEval = lasttages->lazyEval = true;
     573             :     }
     574             : 
     575       18288 :     return eslist;
     576             : }
     577             : 
     578             : /*
     579             :  * Initialize the SQLFunctionCache for a SQL function
     580             :  */
     581             : static void
     582       18302 : init_sql_fcache(FunctionCallInfo fcinfo, Oid collation, bool lazyEvalOK)
     583             : {
     584       18302 :     FmgrInfo   *finfo = fcinfo->flinfo;
     585       18302 :     Oid         foid = finfo->fn_oid;
     586             :     MemoryContext fcontext;
     587             :     MemoryContext oldcontext;
     588             :     Oid         rettype;
     589             :     TupleDesc   rettupdesc;
     590             :     HeapTuple   procedureTuple;
     591             :     Form_pg_proc procedureStruct;
     592             :     SQLFunctionCachePtr fcache;
     593             :     List       *queryTree_list;
     594             :     List       *resulttlist;
     595             :     ListCell   *lc;
     596             :     Datum       tmp;
     597             :     bool        isNull;
     598             : 
     599             :     /*
     600             :      * Create memory context that holds all the SQLFunctionCache data.  It
     601             :      * must be a child of whatever context holds the FmgrInfo.
     602             :      */
     603       18302 :     fcontext = AllocSetContextCreate(finfo->fn_mcxt,
     604             :                                      "SQL function",
     605             :                                      ALLOCSET_DEFAULT_SIZES);
     606             : 
     607       18302 :     oldcontext = MemoryContextSwitchTo(fcontext);
     608             : 
     609             :     /*
     610             :      * Create the struct proper, link it to fcontext and fn_extra.  Once this
     611             :      * is done, we'll be able to recover the memory after failure, even if the
     612             :      * FmgrInfo is long-lived.
     613             :      */
     614       18302 :     fcache = (SQLFunctionCachePtr) palloc0(sizeof(SQLFunctionCache));
     615       18302 :     fcache->fcontext = fcontext;
     616       18302 :     finfo->fn_extra = (void *) fcache;
     617             : 
     618             :     /*
     619             :      * get the procedure tuple corresponding to the given function Oid
     620             :      */
     621       18302 :     procedureTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(foid));
     622       18302 :     if (!HeapTupleIsValid(procedureTuple))
     623           0 :         elog(ERROR, "cache lookup failed for function %u", foid);
     624       18302 :     procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
     625             : 
     626             :     /*
     627             :      * copy function name immediately for use by error reporting callback, and
     628             :      * for use as memory context identifier
     629             :      */
     630       18302 :     fcache->fname = pstrdup(NameStr(procedureStruct->proname));
     631       18302 :     MemoryContextSetIdentifier(fcontext, fcache->fname);
     632             : 
     633             :     /*
     634             :      * Resolve any polymorphism, obtaining the actual result type, and the
     635             :      * corresponding tupdesc if it's a rowtype.
     636             :      */
     637       18302 :     (void) get_call_result_type(fcinfo, &rettype, &rettupdesc);
     638             : 
     639       18302 :     fcache->rettype = rettype;
     640             : 
     641             :     /* Fetch the typlen and byval info for the result type */
     642       18302 :     get_typlenbyval(rettype, &fcache->typlen, &fcache->typbyval);
     643             : 
     644             :     /* Remember whether we're returning setof something */
     645       18302 :     fcache->returnsSet = procedureStruct->proretset;
     646             : 
     647             :     /* Remember if function is STABLE/IMMUTABLE */
     648       18302 :     fcache->readonly_func =
     649       18302 :         (procedureStruct->provolatile != PROVOLATILE_VOLATILE);
     650             : 
     651             :     /*
     652             :      * We need the actual argument types to pass to the parser.  Also make
     653             :      * sure that parameter symbols are considered to have the function's
     654             :      * resolved input collation.
     655             :      */
     656       36604 :     fcache->pinfo = prepare_sql_fn_parse_info(procedureTuple,
     657       18302 :                                               finfo->fn_expr,
     658             :                                               collation);
     659             : 
     660             :     /*
     661             :      * And of course we need the function body text.
     662             :      */
     663       18302 :     tmp = SysCacheGetAttrNotNull(PROCOID, procedureTuple, Anum_pg_proc_prosrc);
     664       18302 :     fcache->src = TextDatumGetCString(tmp);
     665             : 
     666             :     /* If we have prosqlbody, pay attention to that not prosrc. */
     667       18302 :     tmp = SysCacheGetAttr(PROCOID,
     668             :                           procedureTuple,
     669             :                           Anum_pg_proc_prosqlbody,
     670             :                           &isNull);
     671             : 
     672             :     /*
     673             :      * Parse and rewrite the queries in the function text.  Use sublists to
     674             :      * keep track of the original query boundaries.
     675             :      *
     676             :      * Note: since parsing and planning is done in fcontext, we will generate
     677             :      * a lot of cruft that lives as long as the fcache does.  This is annoying
     678             :      * but we'll not worry about it until the module is rewritten to use
     679             :      * plancache.c.
     680             :      */
     681       18302 :     queryTree_list = NIL;
     682       18302 :     if (!isNull)
     683             :     {
     684             :         Node       *n;
     685             :         List       *stored_query_list;
     686             : 
     687        1978 :         n = stringToNode(TextDatumGetCString(tmp));
     688        1978 :         if (IsA(n, List))
     689        1608 :             stored_query_list = linitial_node(List, castNode(List, n));
     690             :         else
     691         370 :             stored_query_list = list_make1(n);
     692             : 
     693        3956 :         foreach(lc, stored_query_list)
     694             :         {
     695        1978 :             Query      *parsetree = lfirst_node(Query, lc);
     696             :             List       *queryTree_sublist;
     697             : 
     698        1978 :             AcquireRewriteLocks(parsetree, true, false);
     699        1978 :             queryTree_sublist = pg_rewrite_query(parsetree);
     700        1978 :             queryTree_list = lappend(queryTree_list, queryTree_sublist);
     701             :         }
     702             :     }
     703             :     else
     704             :     {
     705             :         List       *raw_parsetree_list;
     706             : 
     707       16324 :         raw_parsetree_list = pg_parse_query(fcache->src);
     708             : 
     709       32768 :         foreach(lc, raw_parsetree_list)
     710             :         {
     711       16446 :             RawStmt    *parsetree = lfirst_node(RawStmt, lc);
     712             :             List       *queryTree_sublist;
     713             : 
     714       16446 :             queryTree_sublist = pg_analyze_and_rewrite_withcb(parsetree,
     715       16446 :                                                               fcache->src,
     716             :                                                               (ParserSetupHook) sql_fn_parser_setup,
     717       16446 :                                                               fcache->pinfo,
     718             :                                                               NULL);
     719       16444 :             queryTree_list = lappend(queryTree_list, queryTree_sublist);
     720             :         }
     721             :     }
     722             : 
     723             :     /*
     724             :      * Check that there are no statements we don't want to allow.
     725             :      */
     726       18300 :     check_sql_fn_statements(queryTree_list);
     727             : 
     728             :     /*
     729             :      * Check that the function returns the type it claims to.  Although in
     730             :      * simple cases this was already done when the function was defined, we
     731             :      * have to recheck because database objects used in the function's queries
     732             :      * might have changed type.  We'd have to recheck anyway if the function
     733             :      * had any polymorphic arguments.  Moreover, check_sql_fn_retval takes
     734             :      * care of injecting any required column type coercions.  (But we don't
     735             :      * ask it to insert nulls for dropped columns; the junkfilter handles
     736             :      * that.)
     737             :      *
     738             :      * Note: we set fcache->returnsTuple according to whether we are returning
     739             :      * the whole tuple result or just a single column.  In the latter case we
     740             :      * clear returnsTuple because we need not act different from the scalar
     741             :      * result case, even if it's a rowtype column.  (However, we have to force
     742             :      * lazy eval mode in that case; otherwise we'd need extra code to expand
     743             :      * the rowtype column into multiple columns, since we have no way to
     744             :      * notify the caller that it should do that.)
     745             :      */
     746       18300 :     fcache->returnsTuple = check_sql_fn_retval(queryTree_list,
     747             :                                                rettype,
     748             :                                                rettupdesc,
     749             :                                                false,
     750             :                                                &resulttlist);
     751             : 
     752             :     /*
     753             :      * Construct a JunkFilter we can use to coerce the returned rowtype to the
     754             :      * desired form, unless the result type is VOID, in which case there's
     755             :      * nothing to coerce to.  (XXX Frequently, the JunkFilter isn't doing
     756             :      * anything very interesting, but much of this module expects it to be
     757             :      * there anyway.)
     758             :      */
     759       18294 :     if (rettype != VOIDOID)
     760             :     {
     761       18010 :         TupleTableSlot *slot = MakeSingleTupleTableSlot(NULL,
     762             :                                                         &TTSOpsMinimalTuple);
     763             : 
     764             :         /*
     765             :          * If the result is composite, *and* we are returning the whole tuple
     766             :          * result, we need to insert nulls for any dropped columns.  In the
     767             :          * single-column-result case, there might be dropped columns within
     768             :          * the composite column value, but it's not our problem here.  There
     769             :          * should be no resjunk entries in resulttlist, so in the second case
     770             :          * the JunkFilter is certainly a no-op.
     771             :          */
     772       18010 :         if (rettupdesc && fcache->returnsTuple)
     773        1218 :             fcache->junkFilter = ExecInitJunkFilterConversion(resulttlist,
     774             :                                                               rettupdesc,
     775             :                                                               slot);
     776             :         else
     777       16792 :             fcache->junkFilter = ExecInitJunkFilter(resulttlist, slot);
     778             :     }
     779             : 
     780       18294 :     if (fcache->returnsTuple)
     781             :     {
     782             :         /* Make sure output rowtype is properly blessed */
     783        1242 :         BlessTupleDesc(fcache->junkFilter->jf_resultSlot->tts_tupleDescriptor);
     784             :     }
     785       17052 :     else if (fcache->returnsSet && type_is_rowtype(fcache->rettype))
     786             :     {
     787             :         /*
     788             :          * Returning rowtype as if it were scalar --- materialize won't work.
     789             :          * Right now it's sufficient to override any caller preference for
     790             :          * materialize mode, but to add more smarts in init_execution_state
     791             :          * about this, we'd probably need a three-way flag instead of bool.
     792             :          */
     793           0 :         lazyEvalOK = true;
     794             :     }
     795             : 
     796             :     /* Finally, plan the queries */
     797       18294 :     fcache->func_state = init_execution_state(queryTree_list,
     798             :                                               fcache,
     799             :                                               lazyEvalOK);
     800             : 
     801             :     /* Mark fcache with time of creation to show it's valid */
     802       18288 :     fcache->lxid = MyProc->lxid;
     803       18288 :     fcache->subxid = GetCurrentSubTransactionId();
     804             : 
     805       18288 :     ReleaseSysCache(procedureTuple);
     806             : 
     807       18288 :     MemoryContextSwitchTo(oldcontext);
     808       18288 : }
     809             : 
     810             : /* Start up execution of one execution_state node */
     811             : static void
     812      114250 : postquel_start(execution_state *es, SQLFunctionCachePtr fcache)
     813             : {
     814             :     DestReceiver *dest;
     815             : 
     816             :     Assert(es->qd == NULL);
     817             : 
     818             :     /* Caller should have ensured a suitable snapshot is active */
     819             :     Assert(ActiveSnapshotSet());
     820             : 
     821             :     /*
     822             :      * If this query produces the function result, send its output to the
     823             :      * tuplestore; else discard any output.
     824             :      */
     825      114250 :     if (es->setsResult)
     826             :     {
     827             :         DR_sqlfunction *myState;
     828             : 
     829       73848 :         dest = CreateDestReceiver(DestSQLFunction);
     830             :         /* pass down the needed info to the dest receiver routines */
     831       73848 :         myState = (DR_sqlfunction *) dest;
     832             :         Assert(myState->pub.mydest == DestSQLFunction);
     833       73848 :         myState->tstore = fcache->tstore;
     834       73848 :         myState->cxt = CurrentMemoryContext;
     835       73848 :         myState->filter = fcache->junkFilter;
     836             :     }
     837             :     else
     838       40402 :         dest = None_Receiver;
     839             : 
     840      114250 :     es->qd = CreateQueryDesc(es->stmt,
     841      114250 :                              fcache->src,
     842             :                              GetActiveSnapshot(),
     843             :                              InvalidSnapshot,
     844             :                              dest,
     845             :                              fcache->paramLI,
     846      114250 :                              es->qd ? es->qd->queryEnv : NULL,
     847             :                              0);
     848             : 
     849             :     /* Utility commands don't need Executor. */
     850      114250 :     if (es->qd->operation != CMD_UTILITY)
     851             :     {
     852             :         /*
     853             :          * In lazyEval mode, do not let the executor set up an AfterTrigger
     854             :          * context.  This is necessary not just an optimization, because we
     855             :          * mustn't exit from the function execution with a stacked
     856             :          * AfterTrigger level still active.  We are careful not to select
     857             :          * lazyEval mode for any statement that could possibly queue triggers.
     858             :          */
     859             :         int         eflags;
     860             : 
     861      114094 :         if (es->lazyEval)
     862       72960 :             eflags = EXEC_FLAG_SKIP_TRIGGERS;
     863             :         else
     864       41134 :             eflags = 0;         /* default run-to-completion flags */
     865      114094 :         ExecutorStart(es->qd, eflags);
     866             :     }
     867             : 
     868      114248 :     es->status = F_EXEC_RUN;
     869      114248 : }
     870             : 
     871             : /* Run one execution_state; either to completion or to first result row */
     872             : /* Returns true if we ran to completion */
     873             : static bool
     874      115208 : postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache)
     875             : {
     876             :     bool        result;
     877             : 
     878      115208 :     if (es->qd->operation == CMD_UTILITY)
     879             :     {
     880         156 :         ProcessUtility(es->qd->plannedstmt,
     881         156 :                        fcache->src,
     882             :                        true,    /* protect function cache's parsetree */
     883             :                        PROCESS_UTILITY_QUERY,
     884         156 :                        es->qd->params,
     885         156 :                        es->qd->queryEnv,
     886         156 :                        es->qd->dest,
     887             :                        NULL);
     888          66 :         result = true;          /* never stops early */
     889             :     }
     890             :     else
     891             :     {
     892             :         /* Run regular commands to completion unless lazyEval */
     893      115052 :         uint64      count = (es->lazyEval) ? 1 : 0;
     894             : 
     895      115052 :         ExecutorRun(es->qd, ForwardScanDirection, count, !fcache->returnsSet || !es->lazyEval);
     896             : 
     897             :         /*
     898             :          * If we requested run to completion OR there was no tuple returned,
     899             :          * command must be complete.
     900             :          */
     901      106486 :         result = (count == 0 || es->qd->estate->es_processed == 0);
     902             :     }
     903             : 
     904      106552 :     return result;
     905             : }
     906             : 
     907             : /* Shut down execution of one execution_state node */
     908             : static void
     909      105592 : postquel_end(execution_state *es)
     910             : {
     911             :     /* mark status done to ensure we don't do ExecutorEnd twice */
     912      105592 :     es->status = F_EXEC_DONE;
     913             : 
     914             :     /* Utility commands don't need Executor. */
     915      105592 :     if (es->qd->operation != CMD_UTILITY)
     916             :     {
     917      105526 :         ExecutorFinish(es->qd);
     918      105508 :         ExecutorEnd(es->qd);
     919             :     }
     920             : 
     921      105574 :     es->qd->dest->rDestroy(es->qd->dest);
     922             : 
     923      105574 :     FreeQueryDesc(es->qd);
     924      105574 :     es->qd = NULL;
     925      105574 : }
     926             : 
     927             : /* Build ParamListInfo array representing current arguments */
     928             : static void
     929       74156 : postquel_sub_params(SQLFunctionCachePtr fcache,
     930             :                     FunctionCallInfo fcinfo)
     931             : {
     932       74156 :     int         nargs = fcinfo->nargs;
     933             : 
     934       74156 :     if (nargs > 0)
     935             :     {
     936             :         ParamListInfo paramLI;
     937       63090 :         Oid        *argtypes = fcache->pinfo->argtypes;
     938             : 
     939       63090 :         if (fcache->paramLI == NULL)
     940             :         {
     941        7252 :             paramLI = makeParamList(nargs);
     942        7252 :             fcache->paramLI = paramLI;
     943             :         }
     944             :         else
     945             :         {
     946       55838 :             paramLI = fcache->paramLI;
     947             :             Assert(paramLI->numParams == nargs);
     948             :         }
     949             : 
     950      185296 :         for (int i = 0; i < nargs; i++)
     951             :         {
     952      122206 :             ParamExternData *prm = &paramLI->params[i];
     953             : 
     954             :             /*
     955             :              * If an incoming parameter value is a R/W expanded datum, we
     956             :              * force it to R/O.  We'd be perfectly entitled to scribble on it,
     957             :              * but the problem is that if the parameter is referenced more
     958             :              * than once in the function, earlier references might mutate the
     959             :              * value seen by later references, which won't do at all.  We
     960             :              * could do better if we could be sure of the number of Param
     961             :              * nodes in the function's plans; but we might not have planned
     962             :              * all the statements yet, nor do we have plan tree walker
     963             :              * infrastructure.  (Examining the parse trees is not good enough,
     964             :              * because of possible function inlining during planning.)
     965             :              */
     966      122206 :             prm->isnull = fcinfo->args[i].isnull;
     967      122206 :             prm->value = MakeExpandedObjectReadOnly(fcinfo->args[i].value,
     968             :                                                     prm->isnull,
     969             :                                                     get_typlen(argtypes[i]));
     970      122206 :             prm->pflags = 0;
     971      122206 :             prm->ptype = argtypes[i];
     972             :         }
     973             :     }
     974             :     else
     975       11066 :         fcache->paramLI = NULL;
     976       74156 : }
     977             : 
     978             : /*
     979             :  * Extract the SQL function's value from a single result row.  This is used
     980             :  * both for scalar (non-set) functions and for each row of a lazy-eval set
     981             :  * result.
     982             :  */
     983             : static Datum
     984       58870 : postquel_get_single_result(TupleTableSlot *slot,
     985             :                            FunctionCallInfo fcinfo,
     986             :                            SQLFunctionCachePtr fcache,
     987             :                            MemoryContext resultcontext)
     988             : {
     989             :     Datum       value;
     990             :     MemoryContext oldcontext;
     991             : 
     992             :     /*
     993             :      * Set up to return the function value.  For pass-by-reference datatypes,
     994             :      * be sure to allocate the result in resultcontext, not the current memory
     995             :      * context (which has query lifespan).  We can't leave the data in the
     996             :      * TupleTableSlot because we intend to clear the slot before returning.
     997             :      */
     998       58870 :     oldcontext = MemoryContextSwitchTo(resultcontext);
     999             : 
    1000       58870 :     if (fcache->returnsTuple)
    1001             :     {
    1002             :         /* We must return the whole tuple as a Datum. */
    1003        1410 :         fcinfo->isnull = false;
    1004        1410 :         value = ExecFetchSlotHeapTupleDatum(slot);
    1005             :     }
    1006             :     else
    1007             :     {
    1008             :         /*
    1009             :          * Returning a scalar, which we have to extract from the first column
    1010             :          * of the SELECT result, and then copy into result context if needed.
    1011             :          */
    1012       57460 :         value = slot_getattr(slot, 1, &(fcinfo->isnull));
    1013             : 
    1014       57460 :         if (!fcinfo->isnull)
    1015       57220 :             value = datumCopy(value, fcache->typbyval, fcache->typlen);
    1016             :     }
    1017             : 
    1018       58870 :     MemoryContextSwitchTo(oldcontext);
    1019             : 
    1020       58870 :     return value;
    1021             : }
    1022             : 
    1023             : /*
    1024             :  * fmgr_sql: function call manager for SQL functions
    1025             :  */
    1026             : Datum
    1027       75136 : fmgr_sql(PG_FUNCTION_ARGS)
    1028             : {
    1029             :     SQLFunctionCachePtr fcache;
    1030             :     ErrorContextCallback sqlerrcontext;
    1031             :     MemoryContext oldcontext;
    1032             :     bool        randomAccess;
    1033             :     bool        lazyEvalOK;
    1034             :     bool        is_first;
    1035             :     bool        pushed_snapshot;
    1036             :     execution_state *es;
    1037             :     TupleTableSlot *slot;
    1038             :     Datum       result;
    1039             :     List       *eslist;
    1040             :     ListCell   *eslc;
    1041             : 
    1042             :     /*
    1043             :      * Setup error traceback support for ereport()
    1044             :      */
    1045       75136 :     sqlerrcontext.callback = sql_exec_error_callback;
    1046       75136 :     sqlerrcontext.arg = fcinfo->flinfo;
    1047       75136 :     sqlerrcontext.previous = error_context_stack;
    1048       75136 :     error_context_stack = &sqlerrcontext;
    1049             : 
    1050             :     /* Check call context */
    1051       75136 :     if (fcinfo->flinfo->fn_retset)
    1052             :     {
    1053        4996 :         ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
    1054             : 
    1055             :         /*
    1056             :          * For simplicity, we require callers to support both set eval modes.
    1057             :          * There are cases where we must use one or must use the other, and
    1058             :          * it's not really worthwhile to postpone the check till we know. But
    1059             :          * note we do not require caller to provide an expectedDesc.
    1060             :          */
    1061        4996 :         if (!rsi || !IsA(rsi, ReturnSetInfo) ||
    1062        4996 :             (rsi->allowedModes & SFRM_ValuePerCall) == 0 ||
    1063        4996 :             (rsi->allowedModes & SFRM_Materialize) == 0)
    1064           0 :             ereport(ERROR,
    1065             :                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
    1066             :                      errmsg("set-valued function called in context that cannot accept a set")));
    1067        4996 :         randomAccess = rsi->allowedModes & SFRM_Materialize_Random;
    1068        4996 :         lazyEvalOK = !(rsi->allowedModes & SFRM_Materialize_Preferred);
    1069             :     }
    1070             :     else
    1071             :     {
    1072       70140 :         randomAccess = false;
    1073       70140 :         lazyEvalOK = true;
    1074             :     }
    1075             : 
    1076             :     /*
    1077             :      * Initialize fcache (build plans) if first time through; or re-initialize
    1078             :      * if the cache is stale.
    1079             :      */
    1080       75136 :     fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
    1081             : 
    1082       75136 :     if (fcache != NULL)
    1083             :     {
    1084       56876 :         if (fcache->lxid != MyProc->lxid ||
    1085       56834 :             !SubTransactionIsActive(fcache->subxid))
    1086             :         {
    1087             :             /* It's stale; unlink and delete */
    1088          42 :             fcinfo->flinfo->fn_extra = NULL;
    1089          42 :             MemoryContextDelete(fcache->fcontext);
    1090          42 :             fcache = NULL;
    1091             :         }
    1092             :     }
    1093             : 
    1094       75136 :     if (fcache == NULL)
    1095             :     {
    1096       18302 :         init_sql_fcache(fcinfo, PG_GET_COLLATION(), lazyEvalOK);
    1097       18288 :         fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
    1098             :     }
    1099             : 
    1100             :     /*
    1101             :      * Switch to context in which the fcache lives.  This ensures that our
    1102             :      * tuplestore etc will have sufficient lifetime.  The sub-executor is
    1103             :      * responsible for deleting per-tuple information.  (XXX in the case of a
    1104             :      * long-lived FmgrInfo, this policy represents more memory leakage, but
    1105             :      * it's not entirely clear where to keep stuff instead.)
    1106             :      */
    1107       75122 :     oldcontext = MemoryContextSwitchTo(fcache->fcontext);
    1108             : 
    1109             :     /*
    1110             :      * Find first unfinished query in function, and note whether it's the
    1111             :      * first query.
    1112             :      */
    1113       75122 :     eslist = fcache->func_state;
    1114       75122 :     es = NULL;
    1115       75122 :     is_first = true;
    1116       75122 :     foreach(eslc, eslist)
    1117             :     {
    1118       75116 :         es = (execution_state *) lfirst(eslc);
    1119             : 
    1120       75116 :         while (es && es->status == F_EXEC_DONE)
    1121             :         {
    1122           0 :             is_first = false;
    1123           0 :             es = es->next;
    1124             :         }
    1125             : 
    1126       75116 :         if (es)
    1127       75116 :             break;
    1128             :     }
    1129             : 
    1130             :     /*
    1131             :      * Convert params to appropriate format if starting a fresh execution. (If
    1132             :      * continuing execution, we can re-use prior params.)
    1133             :      */
    1134       75122 :     if (is_first && es && es->status == F_EXEC_START)
    1135       74156 :         postquel_sub_params(fcache, fcinfo);
    1136             : 
    1137             :     /*
    1138             :      * Build tuplestore to hold results, if we don't have one already. Note
    1139             :      * it's in the query-lifespan context.
    1140             :      */
    1141       75122 :     if (!fcache->tstore)
    1142       18474 :         fcache->tstore = tuplestore_begin_heap(randomAccess, false, work_mem);
    1143             : 
    1144             :     /*
    1145             :      * Execute each command in the function one after another until we either
    1146             :      * run out of commands or get a result row from a lazily-evaluated SELECT.
    1147             :      *
    1148             :      * Notes about snapshot management:
    1149             :      *
    1150             :      * In a read-only function, we just use the surrounding query's snapshot.
    1151             :      *
    1152             :      * In a non-read-only function, we rely on the fact that we'll never
    1153             :      * suspend execution between queries of the function: the only reason to
    1154             :      * suspend execution before completion is if we are returning a row from a
    1155             :      * lazily-evaluated SELECT.  So, when first entering this loop, we'll
    1156             :      * either start a new query (and push a fresh snapshot) or re-establish
    1157             :      * the active snapshot from the existing query descriptor.  If we need to
    1158             :      * start a new query in a subsequent execution of the loop, either we need
    1159             :      * a fresh snapshot (and pushed_snapshot is false) or the existing
    1160             :      * snapshot is on the active stack and we can just bump its command ID.
    1161             :      */
    1162       75122 :     pushed_snapshot = false;
    1163      180696 :     while (es)
    1164             :     {
    1165             :         bool        completed;
    1166             : 
    1167      115210 :         if (es->status == F_EXEC_START)
    1168             :         {
    1169             :             /*
    1170             :              * If not read-only, be sure to advance the command counter for
    1171             :              * each command, so that all work to date in this transaction is
    1172             :              * visible.  Take a new snapshot if we don't have one yet,
    1173             :              * otherwise just bump the command ID in the existing snapshot.
    1174             :              */
    1175      114250 :             if (!fcache->readonly_func)
    1176             :             {
    1177      103992 :                 CommandCounterIncrement();
    1178      103992 :                 if (!pushed_snapshot)
    1179             :                 {
    1180      103986 :                     PushActiveSnapshot(GetTransactionSnapshot());
    1181      103986 :                     pushed_snapshot = true;
    1182             :                 }
    1183             :                 else
    1184           6 :                     UpdateActiveSnapshotCommandId();
    1185             :             }
    1186             : 
    1187      114250 :             postquel_start(es, fcache);
    1188             :         }
    1189         960 :         else if (!fcache->readonly_func && !pushed_snapshot)
    1190             :         {
    1191             :             /* Re-establish active snapshot when re-entering function */
    1192         612 :             PushActiveSnapshot(es->qd->snapshot);
    1193         612 :             pushed_snapshot = true;
    1194             :         }
    1195             : 
    1196      115208 :         completed = postquel_getnext(es, fcache);
    1197             : 
    1198             :         /*
    1199             :          * If we ran the command to completion, we can shut it down now. Any
    1200             :          * row(s) we need to return are safely stashed in the tuplestore, and
    1201             :          * we want to be sure that, for example, AFTER triggers get fired
    1202             :          * before we return anything.  Also, if the function doesn't return
    1203             :          * set, we can shut it down anyway because it must be a SELECT and we
    1204             :          * don't care about fetching any more result rows.
    1205             :          */
    1206      106552 :         if (completed || !fcache->returnsSet)
    1207      105592 :             postquel_end(es);
    1208             : 
    1209             :         /*
    1210             :          * Break from loop if we didn't shut down (implying we got a
    1211             :          * lazily-evaluated row).  Otherwise we'll press on till the whole
    1212             :          * function is done, relying on the tuplestore to keep hold of the
    1213             :          * data to eventually be returned.  This is necessary since an
    1214             :          * INSERT/UPDATE/DELETE RETURNING that sets the result might be
    1215             :          * followed by additional rule-inserted commands, and we want to
    1216             :          * finish doing all those commands before we return anything.
    1217             :          */
    1218      106534 :         if (es->status != F_EXEC_DONE)
    1219         960 :             break;
    1220             : 
    1221             :         /*
    1222             :          * Advance to next execution_state, which might be in the next list.
    1223             :          */
    1224      105574 :         es = es->next;
    1225      145662 :         while (!es)
    1226             :         {
    1227      105568 :             eslc = lnext(eslist, eslc);
    1228      105568 :             if (!eslc)
    1229       65480 :                 break;          /* end of function */
    1230             : 
    1231       40088 :             es = (execution_state *) lfirst(eslc);
    1232             : 
    1233             :             /*
    1234             :              * Flush the current snapshot so that we will take a new one for
    1235             :              * the new query list.  This ensures that new snaps are taken at
    1236             :              * original-query boundaries, matching the behavior of interactive
    1237             :              * execution.
    1238             :              */
    1239       40088 :             if (pushed_snapshot)
    1240             :             {
    1241       40088 :                 PopActiveSnapshot();
    1242       40088 :                 pushed_snapshot = false;
    1243             :             }
    1244             :         }
    1245             :     }
    1246             : 
    1247             :     /*
    1248             :      * The tuplestore now contains whatever row(s) we are supposed to return.
    1249             :      */
    1250       66446 :     if (fcache->returnsSet)
    1251             :     {
    1252        4990 :         ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
    1253             : 
    1254        4990 :         if (es)
    1255             :         {
    1256             :             /*
    1257             :              * If we stopped short of being done, we must have a lazy-eval
    1258             :              * row.
    1259             :              */
    1260             :             Assert(es->lazyEval);
    1261             :             /* Re-use the junkfilter's output slot to fetch back the tuple */
    1262             :             Assert(fcache->junkFilter);
    1263         960 :             slot = fcache->junkFilter->jf_resultSlot;
    1264         960 :             if (!tuplestore_gettupleslot(fcache->tstore, true, false, slot))
    1265           0 :                 elog(ERROR, "failed to fetch lazy-eval tuple");
    1266             :             /* Extract the result as a datum, and copy out from the slot */
    1267         960 :             result = postquel_get_single_result(slot, fcinfo,
    1268             :                                                 fcache, oldcontext);
    1269             :             /* Clear the tuplestore, but keep it for next time */
    1270             :             /* NB: this might delete the slot's content, but we don't care */
    1271         960 :             tuplestore_clear(fcache->tstore);
    1272             : 
    1273             :             /*
    1274             :              * Let caller know we're not finished.
    1275             :              */
    1276         960 :             rsi->isDone = ExprMultipleResult;
    1277             : 
    1278             :             /*
    1279             :              * Ensure we will get shut down cleanly if the exprcontext is not
    1280             :              * run to completion.
    1281             :              */
    1282         960 :             if (!fcache->shutdown_reg)
    1283             :             {
    1284         716 :                 RegisterExprContextCallback(rsi->econtext,
    1285             :                                             ShutdownSQLFunction,
    1286             :                                             PointerGetDatum(fcache));
    1287         716 :                 fcache->shutdown_reg = true;
    1288             :             }
    1289             :         }
    1290        4030 :         else if (fcache->lazyEval)
    1291             :         {
    1292             :             /*
    1293             :              * We are done with a lazy evaluation.  Clean up.
    1294             :              */
    1295        3166 :             tuplestore_clear(fcache->tstore);
    1296             : 
    1297             :             /*
    1298             :              * Let caller know we're finished.
    1299             :              */
    1300        3166 :             rsi->isDone = ExprEndResult;
    1301             : 
    1302        3166 :             fcinfo->isnull = true;
    1303        3166 :             result = (Datum) 0;
    1304             : 
    1305             :             /* Deregister shutdown callback, if we made one */
    1306        3166 :             if (fcache->shutdown_reg)
    1307             :             {
    1308         716 :                 UnregisterExprContextCallback(rsi->econtext,
    1309             :                                               ShutdownSQLFunction,
    1310             :                                               PointerGetDatum(fcache));
    1311         716 :                 fcache->shutdown_reg = false;
    1312             :             }
    1313             :         }
    1314             :         else
    1315             :         {
    1316             :             /*
    1317             :              * We are done with a non-lazy evaluation.  Return whatever is in
    1318             :              * the tuplestore.  (It is now caller's responsibility to free the
    1319             :              * tuplestore when done.)
    1320             :              */
    1321         864 :             rsi->returnMode = SFRM_Materialize;
    1322         864 :             rsi->setResult = fcache->tstore;
    1323         864 :             fcache->tstore = NULL;
    1324             :             /* must copy desc because execSRF.c will free it */
    1325         864 :             if (fcache->junkFilter)
    1326         858 :                 rsi->setDesc = CreateTupleDescCopy(fcache->junkFilter->jf_cleanTupType);
    1327             : 
    1328         864 :             fcinfo->isnull = true;
    1329         864 :             result = (Datum) 0;
    1330             : 
    1331             :             /* Deregister shutdown callback, if we made one */
    1332         864 :             if (fcache->shutdown_reg)
    1333             :             {
    1334           0 :                 UnregisterExprContextCallback(rsi->econtext,
    1335             :                                               ShutdownSQLFunction,
    1336             :                                               PointerGetDatum(fcache));
    1337           0 :                 fcache->shutdown_reg = false;
    1338             :             }
    1339             :         }
    1340             :     }
    1341             :     else
    1342             :     {
    1343             :         /*
    1344             :          * Non-set function.  If we got a row, return it; else return NULL.
    1345             :          */
    1346       61456 :         if (fcache->junkFilter)
    1347             :         {
    1348             :             /* Re-use the junkfilter's output slot to fetch back the tuple */
    1349       61258 :             slot = fcache->junkFilter->jf_resultSlot;
    1350       61258 :             if (tuplestore_gettupleslot(fcache->tstore, true, false, slot))
    1351       57910 :                 result = postquel_get_single_result(slot, fcinfo,
    1352             :                                                     fcache, oldcontext);
    1353             :             else
    1354             :             {
    1355        3348 :                 fcinfo->isnull = true;
    1356        3348 :                 result = (Datum) 0;
    1357             :             }
    1358             :         }
    1359             :         else
    1360             :         {
    1361             :             /* Should only get here for VOID functions and procedures */
    1362             :             Assert(fcache->rettype == VOIDOID);
    1363         198 :             fcinfo->isnull = true;
    1364         198 :             result = (Datum) 0;
    1365             :         }
    1366             : 
    1367             :         /* Clear the tuplestore, but keep it for next time */
    1368       61456 :         tuplestore_clear(fcache->tstore);
    1369             :     }
    1370             : 
    1371             :     /* Pop snapshot if we have pushed one */
    1372       66446 :     if (pushed_snapshot)
    1373       55890 :         PopActiveSnapshot();
    1374             : 
    1375             :     /*
    1376             :      * If we've gone through every command in the function, we are done. Reset
    1377             :      * the execution states to start over again on next call.
    1378             :      */
    1379       66446 :     if (es == NULL)
    1380             :     {
    1381      171054 :         foreach(eslc, fcache->func_state)
    1382             :         {
    1383      105568 :             es = (execution_state *) lfirst(eslc);
    1384      211142 :             while (es)
    1385             :             {
    1386      105574 :                 es->status = F_EXEC_START;
    1387      105574 :                 es = es->next;
    1388             :             }
    1389             :         }
    1390             :     }
    1391             : 
    1392       66446 :     error_context_stack = sqlerrcontext.previous;
    1393             : 
    1394       66446 :     MemoryContextSwitchTo(oldcontext);
    1395             : 
    1396       66446 :     return result;
    1397             : }
    1398             : 
    1399             : 
    1400             : /*
    1401             :  * error context callback to let us supply a call-stack traceback
    1402             :  */
    1403             : static void
    1404        8740 : sql_exec_error_callback(void *arg)
    1405             : {
    1406        8740 :     FmgrInfo   *flinfo = (FmgrInfo *) arg;
    1407        8740 :     SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) flinfo->fn_extra;
    1408             :     int         syntaxerrposition;
    1409             : 
    1410             :     /*
    1411             :      * We can do nothing useful if init_sql_fcache() didn't get as far as
    1412             :      * saving the function name
    1413             :      */
    1414        8740 :     if (fcache == NULL || fcache->fname == NULL)
    1415           0 :         return;
    1416             : 
    1417             :     /*
    1418             :      * If there is a syntax error position, convert to internal syntax error
    1419             :      */
    1420        8740 :     syntaxerrposition = geterrposition();
    1421        8740 :     if (syntaxerrposition > 0 && fcache->src != NULL)
    1422             :     {
    1423           2 :         errposition(0);
    1424           2 :         internalerrposition(syntaxerrposition);
    1425           2 :         internalerrquery(fcache->src);
    1426             :     }
    1427             : 
    1428             :     /*
    1429             :      * Try to determine where in the function we failed.  If there is a query
    1430             :      * with non-null QueryDesc, finger it.  (We check this rather than looking
    1431             :      * for F_EXEC_RUN state, so that errors during ExecutorStart or
    1432             :      * ExecutorEnd are blamed on the appropriate query; see postquel_start and
    1433             :      * postquel_end.)
    1434             :      */
    1435        8740 :     if (fcache->func_state)
    1436             :     {
    1437             :         execution_state *es;
    1438             :         int         query_num;
    1439             :         ListCell   *lc;
    1440             : 
    1441        8726 :         es = NULL;
    1442        8726 :         query_num = 1;
    1443        8726 :         foreach(lc, fcache->func_state)
    1444             :         {
    1445        8726 :             es = (execution_state *) lfirst(lc);
    1446        8726 :             while (es)
    1447             :             {
    1448        8726 :                 if (es->qd)
    1449             :                 {
    1450        8726 :                     errcontext("SQL function \"%s\" statement %d",
    1451             :                                fcache->fname, query_num);
    1452        8726 :                     break;
    1453             :                 }
    1454           0 :                 es = es->next;
    1455             :             }
    1456        8726 :             if (es)
    1457        8726 :                 break;
    1458           0 :             query_num++;
    1459             :         }
    1460        8726 :         if (es == NULL)
    1461             :         {
    1462             :             /*
    1463             :              * couldn't identify a running query; might be function entry,
    1464             :              * function exit, or between queries.
    1465             :              */
    1466           0 :             errcontext("SQL function \"%s\"", fcache->fname);
    1467             :         }
    1468             :     }
    1469             :     else
    1470             :     {
    1471             :         /*
    1472             :          * Assume we failed during init_sql_fcache().  (It's possible that the
    1473             :          * function actually has an empty body, but in that case we may as
    1474             :          * well report all errors as being "during startup".)
    1475             :          */
    1476          14 :         errcontext("SQL function \"%s\" during startup", fcache->fname);
    1477             :     }
    1478             : }
    1479             : 
    1480             : 
    1481             : /*
    1482             :  * callback function in case a function-returning-set needs to be shut down
    1483             :  * before it has been run to completion
    1484             :  */
    1485             : static void
    1486           0 : ShutdownSQLFunction(Datum arg)
    1487             : {
    1488           0 :     SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) DatumGetPointer(arg);
    1489             :     execution_state *es;
    1490             :     ListCell   *lc;
    1491             : 
    1492           0 :     foreach(lc, fcache->func_state)
    1493             :     {
    1494           0 :         es = (execution_state *) lfirst(lc);
    1495           0 :         while (es)
    1496             :         {
    1497             :             /* Shut down anything still running */
    1498           0 :             if (es->status == F_EXEC_RUN)
    1499             :             {
    1500             :                 /* Re-establish active snapshot for any called functions */
    1501           0 :                 if (!fcache->readonly_func)
    1502           0 :                     PushActiveSnapshot(es->qd->snapshot);
    1503             : 
    1504           0 :                 postquel_end(es);
    1505             : 
    1506           0 :                 if (!fcache->readonly_func)
    1507           0 :                     PopActiveSnapshot();
    1508             :             }
    1509             : 
    1510             :             /* Reset states to START in case we're called again */
    1511           0 :             es->status = F_EXEC_START;
    1512           0 :             es = es->next;
    1513             :         }
    1514             :     }
    1515             : 
    1516             :     /* Release tuplestore if we have one */
    1517           0 :     if (fcache->tstore)
    1518           0 :         tuplestore_end(fcache->tstore);
    1519           0 :     fcache->tstore = NULL;
    1520             : 
    1521             :     /* execUtils will deregister the callback... */
    1522           0 :     fcache->shutdown_reg = false;
    1523           0 : }
    1524             : 
    1525             : /*
    1526             :  * check_sql_fn_statements
    1527             :  *
    1528             :  * Check statements in an SQL function.  Error out if there is anything that
    1529             :  * is not acceptable.
    1530             :  */
    1531             : void
    1532       53664 : check_sql_fn_statements(List *queryTreeLists)
    1533             : {
    1534             :     ListCell   *lc;
    1535             : 
    1536             :     /* We are given a list of sublists of Queries */
    1537      107566 :     foreach(lc, queryTreeLists)
    1538             :     {
    1539       53908 :         List       *sublist = lfirst_node(List, lc);
    1540             :         ListCell   *lc2;
    1541             : 
    1542      107816 :         foreach(lc2, sublist)
    1543             :         {
    1544       53914 :             Query      *query = lfirst_node(Query, lc2);
    1545             : 
    1546             :             /*
    1547             :              * Disallow calling procedures with output arguments.  The current
    1548             :              * implementation would just throw the output values away, unless
    1549             :              * the statement is the last one.  Per SQL standard, we should
    1550             :              * assign the output values by name.  By disallowing this here, we
    1551             :              * preserve an opportunity for future improvement.
    1552             :              */
    1553       53914 :             if (query->commandType == CMD_UTILITY &&
    1554         218 :                 IsA(query->utilityStmt, CallStmt))
    1555             :             {
    1556          30 :                 CallStmt   *stmt = (CallStmt *) query->utilityStmt;
    1557             : 
    1558          30 :                 if (stmt->outargs != NIL)
    1559           6 :                     ereport(ERROR,
    1560             :                             (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
    1561             :                              errmsg("calling procedures with output arguments is not supported in SQL functions")));
    1562             :             }
    1563             :         }
    1564             :     }
    1565       53658 : }
    1566             : 
    1567             : /*
    1568             :  * check_sql_fn_retval()
    1569             :  *      Check return value of a list of lists of sql parse trees.
    1570             :  *
    1571             :  * The return value of a sql function is the value returned by the last
    1572             :  * canSetTag query in the function.  We do some ad-hoc type checking and
    1573             :  * coercion here to ensure that the function returns what it's supposed to.
    1574             :  * Note that we may actually modify the last query to make it match!
    1575             :  *
    1576             :  * This function returns true if the sql function returns the entire tuple
    1577             :  * result of its final statement, or false if it returns just the first column
    1578             :  * result of that statement.  It throws an error if the final statement doesn't
    1579             :  * return the right type at all.
    1580             :  *
    1581             :  * Note that because we allow "SELECT rowtype_expression", the result can be
    1582             :  * false even when the declared function return type is a rowtype.
    1583             :  *
    1584             :  * For a polymorphic function the passed rettype must be the actual resolved
    1585             :  * output type of the function.  (This means we can't check the type during
    1586             :  * function definition of a polymorphic function.)  If we do see a polymorphic
    1587             :  * rettype we'll throw an error, saying it is not a supported rettype.
    1588             :  *
    1589             :  * If the function returns composite, the passed rettupdesc should describe
    1590             :  * the expected output.  If rettupdesc is NULL, we can't verify that the
    1591             :  * output matches; that should only happen in fmgr_sql_validator(), or when
    1592             :  * the function returns RECORD and the caller doesn't actually care which
    1593             :  * composite type it is.
    1594             :  *
    1595             :  * (Typically, rettype and rettupdesc are computed by get_call_result_type
    1596             :  * or a sibling function.)
    1597             :  *
    1598             :  * In addition to coercing individual output columns, we can modify the
    1599             :  * output to include dummy NULL columns for any dropped columns appearing
    1600             :  * in rettupdesc.  This is done only if the caller asks for it.
    1601             :  *
    1602             :  * If resultTargetList isn't NULL, then *resultTargetList is set to the
    1603             :  * targetlist that defines the final statement's result.  Exception: if the
    1604             :  * function is defined to return VOID then *resultTargetList is set to NIL.
    1605             :  */
    1606             : bool
    1607       65058 : check_sql_fn_retval(List *queryTreeLists,
    1608             :                     Oid rettype, TupleDesc rettupdesc,
    1609             :                     bool insertDroppedCols,
    1610             :                     List **resultTargetList)
    1611             : {
    1612       65058 :     bool        is_tuple_result = false;
    1613             :     Query      *parse;
    1614             :     ListCell   *parse_cell;
    1615             :     List       *tlist;
    1616             :     int         tlistlen;
    1617             :     bool        tlist_is_modifiable;
    1618             :     char        fn_typtype;
    1619       65058 :     List       *upper_tlist = NIL;
    1620       65058 :     bool        upper_tlist_nontrivial = false;
    1621             :     ListCell   *lc;
    1622             : 
    1623       65058 :     if (resultTargetList)
    1624       18300 :         *resultTargetList = NIL;    /* initialize in case of VOID result */
    1625             : 
    1626             :     /*
    1627             :      * If it's declared to return VOID, we don't care what's in the function.
    1628             :      * (This takes care of the procedure case, as well.)
    1629             :      */
    1630       65058 :     if (rettype == VOIDOID)
    1631        1736 :         return false;
    1632             : 
    1633             :     /*
    1634             :      * Find the last canSetTag query in the function body (which is presented
    1635             :      * to us as a list of sublists of Query nodes).  This isn't necessarily
    1636             :      * the last parsetree, because rule rewriting can insert queries after
    1637             :      * what the user wrote.  Note that it might not even be in the last
    1638             :      * sublist, for example if the last query rewrites to DO INSTEAD NOTHING.
    1639             :      * (It might not be unreasonable to throw an error in such a case, but
    1640             :      * this is the historical behavior and it doesn't seem worth changing.)
    1641             :      */
    1642       63322 :     parse = NULL;
    1643       63322 :     parse_cell = NULL;
    1644      126864 :     foreach(lc, queryTreeLists)
    1645             :     {
    1646       63542 :         List       *sublist = lfirst_node(List, lc);
    1647             :         ListCell   *lc2;
    1648             : 
    1649      127090 :         foreach(lc2, sublist)
    1650             :         {
    1651       63548 :             Query      *q = lfirst_node(Query, lc2);
    1652             : 
    1653       63548 :             if (q->canSetTag)
    1654             :             {
    1655       63542 :                 parse = q;
    1656       63542 :                 parse_cell = lc2;
    1657             :             }
    1658             :         }
    1659             :     }
    1660             : 
    1661             :     /*
    1662             :      * If it's a plain SELECT, it returns whatever the targetlist says.
    1663             :      * Otherwise, if it's INSERT/UPDATE/DELETE with RETURNING, it returns
    1664             :      * that. Otherwise, the function return type must be VOID.
    1665             :      *
    1666             :      * Note: eventually replace this test with QueryReturnsTuples?  We'd need
    1667             :      * a more general method of determining the output type, though.  Also, it
    1668             :      * seems too dangerous to consider FETCH or EXECUTE as returning a
    1669             :      * determinable rowtype, since they depend on relatively short-lived
    1670             :      * entities.
    1671             :      */
    1672       63322 :     if (parse &&
    1673       63322 :         parse->commandType == CMD_SELECT)
    1674             :     {
    1675       63220 :         tlist = parse->targetList;
    1676             :         /* tlist is modifiable unless it's a dummy in a setop query */
    1677       63220 :         tlist_is_modifiable = (parse->setOperations == NULL);
    1678             :     }
    1679         102 :     else if (parse &&
    1680         102 :              (parse->commandType == CMD_INSERT ||
    1681           0 :               parse->commandType == CMD_UPDATE ||
    1682           0 :               parse->commandType == CMD_DELETE) &&
    1683         102 :              parse->returningList)
    1684             :     {
    1685         102 :         tlist = parse->returningList;
    1686             :         /* returningList can always be modified */
    1687         102 :         tlist_is_modifiable = true;
    1688             :     }
    1689             :     else
    1690             :     {
    1691             :         /* Empty function body, or last statement is a utility command */
    1692           0 :         ereport(ERROR,
    1693             :                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
    1694             :                  errmsg("return type mismatch in function declared to return %s",
    1695             :                         format_type_be(rettype)),
    1696             :                  errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE RETURNING.")));
    1697             :         return false;           /* keep compiler quiet */
    1698             :     }
    1699             : 
    1700             :     /*
    1701             :      * OK, check that the targetlist returns something matching the declared
    1702             :      * type, and modify it if necessary.  If possible, we insert any coercion
    1703             :      * steps right into the final statement's targetlist.  However, that might
    1704             :      * risk changes in the statement's semantics --- we can't safely change
    1705             :      * the output type of a grouping column, for instance.  In such cases we
    1706             :      * handle coercions by inserting an extra level of Query that effectively
    1707             :      * just does a projection.
    1708             :      */
    1709             : 
    1710             :     /*
    1711             :      * Count the non-junk entries in the result targetlist.
    1712             :      */
    1713       63322 :     tlistlen = ExecCleanTargetListLength(tlist);
    1714             : 
    1715       63322 :     fn_typtype = get_typtype(rettype);
    1716             : 
    1717       63322 :     if (fn_typtype == TYPTYPE_BASE ||
    1718        2964 :         fn_typtype == TYPTYPE_DOMAIN ||
    1719        2958 :         fn_typtype == TYPTYPE_ENUM ||
    1720        2922 :         fn_typtype == TYPTYPE_RANGE ||
    1721             :         fn_typtype == TYPTYPE_MULTIRANGE)
    1722       60424 :     {
    1723             :         /*
    1724             :          * For scalar-type returns, the target list must have exactly one
    1725             :          * non-junk entry, and its type must be coercible to rettype.
    1726             :          */
    1727             :         TargetEntry *tle;
    1728             : 
    1729       60436 :         if (tlistlen != 1)
    1730           6 :             ereport(ERROR,
    1731             :                     (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
    1732             :                      errmsg("return type mismatch in function declared to return %s",
    1733             :                             format_type_be(rettype)),
    1734             :                      errdetail("Final statement must return exactly one column.")));
    1735             : 
    1736             :         /* We assume here that non-junk TLEs must come first in tlists */
    1737       60430 :         tle = (TargetEntry *) linitial(tlist);
    1738             :         Assert(!tle->resjunk);
    1739             : 
    1740       60430 :         if (!coerce_fn_result_column(tle, rettype, -1,
    1741             :                                      tlist_is_modifiable,
    1742             :                                      &upper_tlist,
    1743             :                                      &upper_tlist_nontrivial))
    1744           6 :             ereport(ERROR,
    1745             :                     (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
    1746             :                      errmsg("return type mismatch in function declared to return %s",
    1747             :                             format_type_be(rettype)),
    1748             :                      errdetail("Actual return type is %s.",
    1749             :                                format_type_be(exprType((Node *) tle->expr)))));
    1750             :     }
    1751        2886 :     else if (fn_typtype == TYPTYPE_COMPOSITE || rettype == RECORDOID)
    1752        2748 :     {
    1753             :         /*
    1754             :          * Returns a rowtype.
    1755             :          *
    1756             :          * Note that we will not consider a domain over composite to be a
    1757             :          * "rowtype" return type; it goes through the scalar case above.  This
    1758             :          * is because we only provide column-by-column implicit casting, and
    1759             :          * will not cast the complete record result.  So the only way to
    1760             :          * produce a domain-over-composite result is to compute it as an
    1761             :          * explicit single-column result.  The single-composite-column code
    1762             :          * path just below could handle such cases, but it won't be reached.
    1763             :          */
    1764             :         int         tupnatts;   /* physical number of columns in tuple */
    1765             :         int         tuplogcols; /* # of nondeleted columns in tuple */
    1766             :         int         colindex;   /* physical column index */
    1767             : 
    1768             :         /*
    1769             :          * If the target list has one non-junk entry, and that expression has
    1770             :          * or can be coerced to the declared return type, take it as the
    1771             :          * result.  This allows, for example, 'SELECT func2()', where func2
    1772             :          * has the same composite return type as the function that's calling
    1773             :          * it.  This provision creates some ambiguity --- maybe the expression
    1774             :          * was meant to be the lone field of the composite result --- but it
    1775             :          * works well enough as long as we don't get too enthusiastic about
    1776             :          * inventing coercions from scalar to composite types.
    1777             :          *
    1778             :          * XXX Note that if rettype is RECORD and the expression is of a named
    1779             :          * composite type, or vice versa, this coercion will succeed, whether
    1780             :          * or not the record type really matches.  For the moment we rely on
    1781             :          * runtime type checking to catch any discrepancy, but it'd be nice to
    1782             :          * do better at parse time.
    1783             :          */
    1784        2880 :         if (tlistlen == 1)
    1785             :         {
    1786         192 :             TargetEntry *tle = (TargetEntry *) linitial(tlist);
    1787             : 
    1788             :             Assert(!tle->resjunk);
    1789         192 :             if (coerce_fn_result_column(tle, rettype, -1,
    1790             :                                         tlist_is_modifiable,
    1791             :                                         &upper_tlist,
    1792             :                                         &upper_tlist_nontrivial))
    1793             :             {
    1794             :                 /* Note that we're NOT setting is_tuple_result */
    1795          72 :                 goto tlist_coercion_finished;
    1796             :             }
    1797             :         }
    1798             : 
    1799             :         /*
    1800             :          * If the caller didn't provide an expected tupdesc, we can't do any
    1801             :          * further checking.  Assume we're returning the whole tuple.
    1802             :          */
    1803        2808 :         if (rettupdesc == NULL)
    1804             :         {
    1805             :             /* Return tlist if requested */
    1806          48 :             if (resultTargetList)
    1807          24 :                 *resultTargetList = tlist;
    1808          48 :             return true;
    1809             :         }
    1810             : 
    1811             :         /*
    1812             :          * Verify that the targetlist matches the return tuple type.  We scan
    1813             :          * the non-resjunk columns, and coerce them if necessary to match the
    1814             :          * datatypes of the non-deleted attributes.  For deleted attributes,
    1815             :          * insert NULL result columns if the caller asked for that.
    1816             :          */
    1817        2760 :         tupnatts = rettupdesc->natts;
    1818        2760 :         tuplogcols = 0;         /* we'll count nondeleted cols as we go */
    1819        2760 :         colindex = 0;
    1820             : 
    1821       13842 :         foreach(lc, tlist)
    1822             :         {
    1823       11094 :             TargetEntry *tle = (TargetEntry *) lfirst(lc);
    1824             :             Form_pg_attribute attr;
    1825             : 
    1826             :             /* resjunk columns can simply be ignored */
    1827       11094 :             if (tle->resjunk)
    1828           0 :                 continue;
    1829             : 
    1830             :             do
    1831             :             {
    1832       11178 :                 colindex++;
    1833       11178 :                 if (colindex > tupnatts)
    1834           0 :                     ereport(ERROR,
    1835             :                             (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
    1836             :                              errmsg("return type mismatch in function declared to return %s",
    1837             :                                     format_type_be(rettype)),
    1838             :                              errdetail("Final statement returns too many columns.")));
    1839       11178 :                 attr = TupleDescAttr(rettupdesc, colindex - 1);
    1840       11178 :                 if (attr->attisdropped && insertDroppedCols)
    1841             :                 {
    1842             :                     Expr       *null_expr;
    1843             : 
    1844             :                     /* The type of the null we insert isn't important */
    1845           6 :                     null_expr = (Expr *) makeConst(INT4OID,
    1846             :                                                    -1,
    1847             :                                                    InvalidOid,
    1848             :                                                    sizeof(int32),
    1849             :                                                    (Datum) 0,
    1850             :                                                    true,    /* isnull */
    1851             :                                                    true /* byval */ );
    1852           6 :                     upper_tlist = lappend(upper_tlist,
    1853           6 :                                           makeTargetEntry(null_expr,
    1854           6 :                                                           list_length(upper_tlist) + 1,
    1855             :                                                           NULL,
    1856             :                                                           false));
    1857           6 :                     upper_tlist_nontrivial = true;
    1858             :                 }
    1859       11178 :             } while (attr->attisdropped);
    1860       11094 :             tuplogcols++;
    1861             : 
    1862       11094 :             if (!coerce_fn_result_column(tle,
    1863             :                                          attr->atttypid, attr->atttypmod,
    1864             :                                          tlist_is_modifiable,
    1865             :                                          &upper_tlist,
    1866             :                                          &upper_tlist_nontrivial))
    1867          12 :                 ereport(ERROR,
    1868             :                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
    1869             :                          errmsg("return type mismatch in function declared to return %s",
    1870             :                                 format_type_be(rettype)),
    1871             :                          errdetail("Final statement returns %s instead of %s at column %d.",
    1872             :                                    format_type_be(exprType((Node *) tle->expr)),
    1873             :                                    format_type_be(attr->atttypid),
    1874             :                                    tuplogcols)));
    1875             :         }
    1876             : 
    1877             :         /* remaining columns in rettupdesc had better all be dropped */
    1878        2748 :         for (colindex++; colindex <= tupnatts; colindex++)
    1879             :         {
    1880           0 :             if (!TupleDescAttr(rettupdesc, colindex - 1)->attisdropped)
    1881           0 :                 ereport(ERROR,
    1882             :                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
    1883             :                          errmsg("return type mismatch in function declared to return %s",
    1884             :                                 format_type_be(rettype)),
    1885             :                          errdetail("Final statement returns too few columns.")));
    1886           0 :             if (insertDroppedCols)
    1887             :             {
    1888             :                 Expr       *null_expr;
    1889             : 
    1890             :                 /* The type of the null we insert isn't important */
    1891           0 :                 null_expr = (Expr *) makeConst(INT4OID,
    1892             :                                                -1,
    1893             :                                                InvalidOid,
    1894             :                                                sizeof(int32),
    1895             :                                                (Datum) 0,
    1896             :                                                true,    /* isnull */
    1897             :                                                true /* byval */ );
    1898           0 :                 upper_tlist = lappend(upper_tlist,
    1899           0 :                                       makeTargetEntry(null_expr,
    1900           0 :                                                       list_length(upper_tlist) + 1,
    1901             :                                                       NULL,
    1902             :                                                       false));
    1903           0 :                 upper_tlist_nontrivial = true;
    1904             :             }
    1905             :         }
    1906             : 
    1907             :         /* Report that we are returning entire tuple result */
    1908        2748 :         is_tuple_result = true;
    1909             :     }
    1910             :     else
    1911           6 :         ereport(ERROR,
    1912             :                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
    1913             :                  errmsg("return type %s is not supported for SQL functions",
    1914             :                         format_type_be(rettype))));
    1915             : 
    1916       63244 : tlist_coercion_finished:
    1917             : 
    1918             :     /*
    1919             :      * If necessary, modify the final Query by injecting an extra Query level
    1920             :      * that just performs a projection.  (It'd be dubious to do this to a
    1921             :      * non-SELECT query, but we never have to; RETURNING lists can always be
    1922             :      * modified in-place.)
    1923             :      */
    1924       63244 :     if (upper_tlist_nontrivial)
    1925             :     {
    1926             :         Query      *newquery;
    1927             :         List       *colnames;
    1928             :         RangeTblEntry *rte;
    1929             :         RangeTblRef *rtr;
    1930             : 
    1931             :         Assert(parse->commandType == CMD_SELECT);
    1932             : 
    1933             :         /* Most of the upper Query struct can be left as zeroes/nulls */
    1934          66 :         newquery = makeNode(Query);
    1935          66 :         newquery->commandType = CMD_SELECT;
    1936          66 :         newquery->querySource = parse->querySource;
    1937          66 :         newquery->canSetTag = true;
    1938          66 :         newquery->targetList = upper_tlist;
    1939             : 
    1940             :         /* We need a moderately realistic colnames list for the subquery RTE */
    1941          66 :         colnames = NIL;
    1942         180 :         foreach(lc, parse->targetList)
    1943             :         {
    1944         114 :             TargetEntry *tle = (TargetEntry *) lfirst(lc);
    1945             : 
    1946         114 :             if (tle->resjunk)
    1947           0 :                 continue;
    1948         114 :             colnames = lappend(colnames,
    1949         114 :                                makeString(tle->resname ? tle->resname : ""));
    1950             :         }
    1951             : 
    1952             :         /* Build a suitable RTE for the subquery */
    1953          66 :         rte = makeNode(RangeTblEntry);
    1954          66 :         rte->rtekind = RTE_SUBQUERY;
    1955          66 :         rte->subquery = parse;
    1956          66 :         rte->eref = rte->alias = makeAlias("*SELECT*", colnames);
    1957          66 :         rte->lateral = false;
    1958          66 :         rte->inh = false;
    1959          66 :         rte->inFromCl = true;
    1960          66 :         newquery->rtable = list_make1(rte);
    1961             : 
    1962          66 :         rtr = makeNode(RangeTblRef);
    1963          66 :         rtr->rtindex = 1;
    1964          66 :         newquery->jointree = makeFromExpr(list_make1(rtr), NULL);
    1965             : 
    1966             :         /* Replace original query in the correct element of the query list */
    1967          66 :         lfirst(parse_cell) = newquery;
    1968             :     }
    1969             : 
    1970             :     /* Return tlist (possibly modified) if requested */
    1971       63244 :     if (resultTargetList)
    1972       17986 :         *resultTargetList = upper_tlist;
    1973             : 
    1974       63244 :     return is_tuple_result;
    1975             : }
    1976             : 
    1977             : /*
    1978             :  * Process one function result column for check_sql_fn_retval
    1979             :  *
    1980             :  * Coerce the output value to the required type/typmod, and add a column
    1981             :  * to *upper_tlist for it.  Set *upper_tlist_nontrivial to true if we
    1982             :  * add an upper tlist item that's not just a Var.
    1983             :  *
    1984             :  * Returns true if OK, false if could not coerce to required type
    1985             :  * (in which case, no changes have been made)
    1986             :  */
    1987             : static bool
    1988       71716 : coerce_fn_result_column(TargetEntry *src_tle,
    1989             :                         Oid res_type,
    1990             :                         int32 res_typmod,
    1991             :                         bool tlist_is_modifiable,
    1992             :                         List **upper_tlist,
    1993             :                         bool *upper_tlist_nontrivial)
    1994             : {
    1995             :     TargetEntry *new_tle;
    1996             :     Expr       *new_tle_expr;
    1997             :     Node       *cast_result;
    1998             : 
    1999             :     /*
    2000             :      * If the TLE has a sortgroupref marking, don't change it, as it probably
    2001             :      * is referenced by ORDER BY, DISTINCT, etc, and changing its type would
    2002             :      * break query semantics.  Otherwise, it's safe to modify in-place unless
    2003             :      * the query as a whole has issues with that.
    2004             :      */
    2005       71716 :     if (tlist_is_modifiable && src_tle->ressortgroupref == 0)
    2006             :     {
    2007             :         /* OK to modify src_tle in place, if necessary */
    2008      142552 :         cast_result = coerce_to_target_type(NULL,
    2009       71276 :                                             (Node *) src_tle->expr,
    2010       71276 :                                             exprType((Node *) src_tle->expr),
    2011             :                                             res_type, res_typmod,
    2012             :                                             COERCION_ASSIGNMENT,
    2013             :                                             COERCE_IMPLICIT_CAST,
    2014             :                                             -1);
    2015       71276 :         if (cast_result == NULL)
    2016         138 :             return false;
    2017       71138 :         assign_expr_collations(NULL, cast_result);
    2018       71138 :         src_tle->expr = (Expr *) cast_result;
    2019             :         /* Make a Var referencing the possibly-modified TLE */
    2020       71138 :         new_tle_expr = (Expr *) makeVarFromTargetEntry(1, src_tle);
    2021             :     }
    2022             :     else
    2023             :     {
    2024             :         /* Any casting must happen in the upper tlist */
    2025         440 :         Var        *var = makeVarFromTargetEntry(1, src_tle);
    2026             : 
    2027         440 :         cast_result = coerce_to_target_type(NULL,
    2028             :                                             (Node *) var,
    2029             :                                             var->vartype,
    2030             :                                             res_type, res_typmod,
    2031             :                                             COERCION_ASSIGNMENT,
    2032             :                                             COERCE_IMPLICIT_CAST,
    2033             :                                             -1);
    2034         440 :         if (cast_result == NULL)
    2035           0 :             return false;
    2036         440 :         assign_expr_collations(NULL, cast_result);
    2037             :         /* Did the coercion actually do anything? */
    2038         440 :         if (cast_result != (Node *) var)
    2039          84 :             *upper_tlist_nontrivial = true;
    2040         440 :         new_tle_expr = (Expr *) cast_result;
    2041             :     }
    2042      143156 :     new_tle = makeTargetEntry(new_tle_expr,
    2043       71578 :                               list_length(*upper_tlist) + 1,
    2044             :                               src_tle->resname, false);
    2045       71578 :     *upper_tlist = lappend(*upper_tlist, new_tle);
    2046       71578 :     return true;
    2047             : }
    2048             : 
    2049             : 
    2050             : /*
    2051             :  * CreateSQLFunctionDestReceiver -- create a suitable DestReceiver object
    2052             :  */
    2053             : DestReceiver *
    2054       73848 : CreateSQLFunctionDestReceiver(void)
    2055             : {
    2056       73848 :     DR_sqlfunction *self = (DR_sqlfunction *) palloc0(sizeof(DR_sqlfunction));
    2057             : 
    2058       73848 :     self->pub.receiveSlot = sqlfunction_receive;
    2059       73848 :     self->pub.rStartup = sqlfunction_startup;
    2060       73848 :     self->pub.rShutdown = sqlfunction_shutdown;
    2061       73848 :     self->pub.rDestroy = sqlfunction_destroy;
    2062       73848 :     self->pub.mydest = DestSQLFunction;
    2063             : 
    2064             :     /* private fields will be set by postquel_start */
    2065             : 
    2066       73848 :     return (DestReceiver *) self;
    2067             : }
    2068             : 
    2069             : /*
    2070             :  * sqlfunction_startup --- executor startup
    2071             :  */
    2072             : static void
    2073       74806 : sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
    2074             : {
    2075             :     /* no-op */
    2076       74806 : }
    2077             : 
    2078             : /*
    2079             :  * sqlfunction_receive --- receive one tuple
    2080             :  */
    2081             : static bool
    2082      181202 : sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self)
    2083             : {
    2084      181202 :     DR_sqlfunction *myState = (DR_sqlfunction *) self;
    2085             : 
    2086             :     /* Filter tuple as needed */
    2087      181202 :     slot = ExecFilterJunk(myState->filter, slot);
    2088             : 
    2089             :     /* Store the filtered tuple into the tuplestore */
    2090      181202 :     tuplestore_puttupleslot(myState->tstore, slot);
    2091             : 
    2092      181202 :     return true;
    2093             : }
    2094             : 
    2095             : /*
    2096             :  * sqlfunction_shutdown --- executor end
    2097             :  */
    2098             : static void
    2099       66242 : sqlfunction_shutdown(DestReceiver *self)
    2100             : {
    2101             :     /* no-op */
    2102       66242 : }
    2103             : 
    2104             : /*
    2105             :  * sqlfunction_destroy --- release DestReceiver object
    2106             :  */
    2107             : static void
    2108       65282 : sqlfunction_destroy(DestReceiver *self)
    2109             : {
    2110       65282 :     pfree(self);
    2111       65282 : }

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