LCOV - code coverage report
Current view: top level - contrib/spi - refint.c (source / functions) Hit Total Coverage
Test: PostgreSQL 18devel Lines: 176 210 83.8 %
Date: 2025-04-24 12:15:10 Functions: 6 6 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*
       2             :  * contrib/spi/refint.c
       3             :  *
       4             :  *
       5             :  * refint.c --  set of functions to define referential integrity
       6             :  *      constraints using general triggers.
       7             :  */
       8             : #include "postgres.h"
       9             : 
      10             : #include <ctype.h>
      11             : 
      12             : #include "commands/trigger.h"
      13             : #include "executor/spi.h"
      14             : #include "utils/builtins.h"
      15             : #include "utils/memutils.h"
      16             : #include "utils/rel.h"
      17             : 
      18           2 : PG_MODULE_MAGIC_EXT(
      19             :                     .name = "refint",
      20             :                     .version = PG_VERSION
      21             : );
      22             : 
      23             : typedef struct
      24             : {
      25             :     char       *ident;
      26             :     int         nplans;
      27             :     SPIPlanPtr *splan;
      28             : } EPlan;
      29             : 
      30             : static EPlan *FPlans = NULL;
      31             : static int  nFPlans = 0;
      32             : static EPlan *PPlans = NULL;
      33             : static int  nPPlans = 0;
      34             : 
      35             : static EPlan *find_plan(char *ident, EPlan **eplan, int *nplans);
      36             : 
      37             : /*
      38             :  * check_primary_key () -- check that key in tuple being inserted/updated
      39             :  *           references existing tuple in "primary" table.
      40             :  * Though it's called without args You have to specify referenced
      41             :  * table/keys while creating trigger:  key field names in triggered table,
      42             :  * referenced table name, referenced key field names:
      43             :  * EXECUTE PROCEDURE
      44             :  * check_primary_key ('Fkey1', 'Fkey2', 'Ptable', 'Pkey1', 'Pkey2').
      45             :  */
      46             : 
      47           4 : PG_FUNCTION_INFO_V1(check_primary_key);
      48             : 
      49             : Datum
      50          38 : check_primary_key(PG_FUNCTION_ARGS)
      51             : {
      52          38 :     TriggerData *trigdata = (TriggerData *) fcinfo->context;
      53             :     Trigger    *trigger;        /* to get trigger name */
      54             :     int         nargs;          /* # of args specified in CREATE TRIGGER */
      55             :     char      **args;           /* arguments: column names and table name */
      56             :     int         nkeys;          /* # of key columns (= nargs / 2) */
      57             :     Datum      *kvals;          /* key values */
      58             :     char       *relname;        /* referenced relation name */
      59             :     Relation    rel;            /* triggered relation */
      60          38 :     HeapTuple   tuple = NULL;   /* tuple to return */
      61             :     TupleDesc   tupdesc;        /* tuple description */
      62             :     EPlan      *plan;           /* prepared plan */
      63          38 :     Oid        *argtypes = NULL;    /* key types to prepare execution plan */
      64             :     bool        isnull;         /* to know is some column NULL or not */
      65             :     char        ident[2 * NAMEDATALEN]; /* to identify myself */
      66             :     int         ret;
      67             :     int         i;
      68             : 
      69             : #ifdef  DEBUG_QUERY
      70             :     elog(DEBUG4, "check_primary_key: Enter Function");
      71             : #endif
      72             : 
      73             :     /*
      74             :      * Some checks first...
      75             :      */
      76             : 
      77             :     /* Called by trigger manager ? */
      78          38 :     if (!CALLED_AS_TRIGGER(fcinfo))
      79             :         /* internal error */
      80           0 :         elog(ERROR, "check_primary_key: not fired by trigger manager");
      81             : 
      82             :     /* Should be called for ROW trigger */
      83          38 :     if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
      84             :         /* internal error */
      85           0 :         elog(ERROR, "check_primary_key: must be fired for row");
      86             : 
      87          38 :     if (!TRIGGER_FIRED_AFTER(trigdata->tg_event))
      88             :         /* internal error */
      89           0 :         elog(ERROR, "check_primary_key: must be fired by AFTER trigger");
      90             : 
      91             :     /* If INSERTion then must check Tuple to being inserted */
      92          38 :     if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
      93          32 :         tuple = trigdata->tg_trigtuple;
      94             : 
      95             :     /* Not should be called for DELETE */
      96           6 :     else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
      97             :         /* internal error */
      98           0 :         elog(ERROR, "check_primary_key: cannot process DELETE events");
      99             : 
     100             :     /* If UPDATE, then must check new Tuple, not old one */
     101             :     else
     102           6 :         tuple = trigdata->tg_newtuple;
     103             : 
     104          38 :     trigger = trigdata->tg_trigger;
     105          38 :     nargs = trigger->tgnargs;
     106          38 :     args = trigger->tgargs;
     107             : 
     108          38 :     if (nargs % 2 != 1)         /* odd number of arguments! */
     109             :         /* internal error */
     110           0 :         elog(ERROR, "check_primary_key: odd number of arguments should be specified");
     111             : 
     112          38 :     nkeys = nargs / 2;
     113          38 :     relname = args[nkeys];
     114          38 :     rel = trigdata->tg_relation;
     115          38 :     tupdesc = rel->rd_att;
     116             : 
     117             :     /* Connect to SPI manager */
     118          38 :     SPI_connect();
     119             : 
     120             :     /*
     121             :      * We use SPI plan preparation feature, so allocate space to place key
     122             :      * values.
     123             :      */
     124          38 :     kvals = (Datum *) palloc(nkeys * sizeof(Datum));
     125             : 
     126             :     /*
     127             :      * Construct ident string as TriggerName $ TriggeredRelationId and try to
     128             :      * find prepared execution plan.
     129             :      */
     130          38 :     snprintf(ident, sizeof(ident), "%s$%u", trigger->tgname, rel->rd_id);
     131          38 :     plan = find_plan(ident, &PPlans, &nPPlans);
     132             : 
     133             :     /* if there is no plan then allocate argtypes for preparation */
     134          38 :     if (plan->nplans <= 0)
     135           6 :         argtypes = (Oid *) palloc(nkeys * sizeof(Oid));
     136             : 
     137             :     /* For each column in key ... */
     138         100 :     for (i = 0; i < nkeys; i++)
     139             :     {
     140             :         /* get index of column in tuple */
     141          62 :         int         fnumber = SPI_fnumber(tupdesc, args[i]);
     142             : 
     143             :         /* Bad guys may give us un-existing column in CREATE TRIGGER */
     144          62 :         if (fnumber <= 0)
     145           0 :             ereport(ERROR,
     146             :                     (errcode(ERRCODE_UNDEFINED_COLUMN),
     147             :                      errmsg("there is no attribute \"%s\" in relation \"%s\"",
     148             :                             args[i], SPI_getrelname(rel))));
     149             : 
     150             :         /* Well, get binary (in internal format) value of column */
     151          62 :         kvals[i] = SPI_getbinval(tuple, tupdesc, fnumber, &isnull);
     152             : 
     153             :         /*
     154             :          * If it's NULL then nothing to do! DON'T FORGET call SPI_finish ()!
     155             :          * DON'T FORGET return tuple! Executor inserts tuple you're returning!
     156             :          * If you return NULL then nothing will be inserted!
     157             :          */
     158          62 :         if (isnull)
     159             :         {
     160           0 :             SPI_finish();
     161           0 :             return PointerGetDatum(tuple);
     162             :         }
     163             : 
     164          62 :         if (plan->nplans <= 0)    /* Get typeId of column */
     165          10 :             argtypes[i] = SPI_gettypeid(tupdesc, fnumber);
     166             :     }
     167             : 
     168             :     /*
     169             :      * If we have to prepare plan ...
     170             :      */
     171          38 :     if (plan->nplans <= 0)
     172             :     {
     173             :         SPIPlanPtr  pplan;
     174             :         char        sql[8192];
     175             : 
     176             :         /*
     177             :          * Construct query: SELECT 1 FROM _referenced_relation_ WHERE Pkey1 =
     178             :          * $1 [AND Pkey2 = $2 [...]]
     179             :          */
     180           6 :         snprintf(sql, sizeof(sql), "select 1 from %s where ", relname);
     181          16 :         for (i = 0; i < nkeys; i++)
     182             :         {
     183          10 :             snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql), "%s = $%d %s",
     184          20 :                      args[i + nkeys + 1], i + 1, (i < nkeys - 1) ? "and " : "");
     185             :         }
     186             : 
     187             :         /* Prepare plan for query */
     188           6 :         pplan = SPI_prepare(sql, nkeys, argtypes);
     189           6 :         if (pplan == NULL)
     190             :             /* internal error */
     191           0 :             elog(ERROR, "check_primary_key: SPI_prepare returned %s", SPI_result_code_string(SPI_result));
     192             : 
     193             :         /*
     194             :          * Remember that SPI_prepare places plan in current memory context -
     195             :          * so, we have to save plan in TopMemoryContext for later use.
     196             :          */
     197           6 :         if (SPI_keepplan(pplan))
     198             :             /* internal error */
     199           0 :             elog(ERROR, "check_primary_key: SPI_keepplan failed");
     200           6 :         plan->splan = (SPIPlanPtr *) MemoryContextAlloc(TopMemoryContext,
     201             :                                                         sizeof(SPIPlanPtr));
     202           6 :         *(plan->splan) = pplan;
     203           6 :         plan->nplans = 1;
     204             :     }
     205             : 
     206             :     /*
     207             :      * Ok, execute prepared plan.
     208             :      */
     209          38 :     ret = SPI_execp(*(plan->splan), kvals, NULL, 1);
     210             :     /* we have no NULLs - so we pass   ^^^^   here */
     211             : 
     212          38 :     if (ret < 0)
     213             :         /* internal error */
     214           0 :         elog(ERROR, "check_primary_key: SPI_execp returned %d", ret);
     215             : 
     216             :     /*
     217             :      * If there are no tuples returned by SELECT then ...
     218             :      */
     219          38 :     if (SPI_processed == 0)
     220           6 :         ereport(ERROR,
     221             :                 (errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
     222             :                  errmsg("tuple references non-existent key"),
     223             :                  errdetail("Trigger \"%s\" found tuple referencing non-existent key in \"%s\".", trigger->tgname, relname)));
     224             : 
     225          32 :     SPI_finish();
     226             : 
     227          32 :     return PointerGetDatum(tuple);
     228             : }
     229             : 
     230             : /*
     231             :  * check_foreign_key () -- check that key in tuple being deleted/updated
     232             :  *           is not referenced by tuples in "foreign" table(s).
     233             :  * Though it's called without args You have to specify (while creating trigger):
     234             :  * number of references, action to do if key referenced
     235             :  * ('restrict' | 'setnull' | 'cascade'), key field names in triggered
     236             :  * ("primary") table and referencing table(s)/keys:
     237             :  * EXECUTE PROCEDURE
     238             :  * check_foreign_key (2, 'restrict', 'Pkey1', 'Pkey2',
     239             :  * 'Ftable1', 'Fkey11', 'Fkey12', 'Ftable2', 'Fkey21', 'Fkey22').
     240             :  */
     241             : 
     242           4 : PG_FUNCTION_INFO_V1(check_foreign_key);
     243             : 
     244             : Datum
     245          12 : check_foreign_key(PG_FUNCTION_ARGS)
     246             : {
     247          12 :     TriggerData *trigdata = (TriggerData *) fcinfo->context;
     248             :     Trigger    *trigger;        /* to get trigger name */
     249             :     int         nargs;          /* # of args specified in CREATE TRIGGER */
     250             :     char      **args;           /* arguments: as described above */
     251             :     char      **args_temp;
     252             :     int         nrefs;          /* number of references (== # of plans) */
     253             :     char        action;         /* 'R'estrict | 'S'etnull | 'C'ascade */
     254             :     int         nkeys;          /* # of key columns */
     255             :     Datum      *kvals;          /* key values */
     256             :     char       *relname;        /* referencing relation name */
     257             :     Relation    rel;            /* triggered relation */
     258          12 :     HeapTuple   trigtuple = NULL;   /* tuple to being changed */
     259          12 :     HeapTuple   newtuple = NULL;    /* tuple to return */
     260             :     TupleDesc   tupdesc;        /* tuple description */
     261             :     EPlan      *plan;           /* prepared plan(s) */
     262          12 :     Oid        *argtypes = NULL;    /* key types to prepare execution plan */
     263             :     bool        isnull;         /* to know is some column NULL or not */
     264          12 :     bool        isequal = true; /* are keys in both tuples equal (in UPDATE) */
     265             :     char        ident[2 * NAMEDATALEN]; /* to identify myself */
     266          12 :     int         is_update = 0;
     267             :     int         ret;
     268             :     int         i,
     269             :                 r;
     270             : 
     271             : #ifdef DEBUG_QUERY
     272             :     elog(DEBUG4, "check_foreign_key: Enter Function");
     273             : #endif
     274             : 
     275             :     /*
     276             :      * Some checks first...
     277             :      */
     278             : 
     279             :     /* Called by trigger manager ? */
     280          12 :     if (!CALLED_AS_TRIGGER(fcinfo))
     281             :         /* internal error */
     282           0 :         elog(ERROR, "check_foreign_key: not fired by trigger manager");
     283             : 
     284             :     /* Should be called for ROW trigger */
     285          12 :     if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
     286             :         /* internal error */
     287           0 :         elog(ERROR, "check_foreign_key: must be fired for row");
     288             : 
     289             :     /* Not should be called for INSERT */
     290          12 :     if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
     291             :         /* internal error */
     292           0 :         elog(ERROR, "check_foreign_key: cannot process INSERT events");
     293             : 
     294          12 :     if (!TRIGGER_FIRED_AFTER(trigdata->tg_event))
     295             :         /* internal error */
     296           0 :         elog(ERROR, "check_foreign_key: must be fired by AFTER trigger");
     297             : 
     298             :     /* Have to check tg_trigtuple - tuple being deleted */
     299          12 :     trigtuple = trigdata->tg_trigtuple;
     300             : 
     301             :     /*
     302             :      * But if this is UPDATE then we have to return tg_newtuple. Also, if key
     303             :      * in tg_newtuple is the same as in tg_trigtuple then nothing to do.
     304             :      */
     305          12 :     is_update = 0;
     306          12 :     if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
     307             :     {
     308           4 :         newtuple = trigdata->tg_newtuple;
     309           4 :         is_update = 1;
     310             :     }
     311          12 :     trigger = trigdata->tg_trigger;
     312          12 :     nargs = trigger->tgnargs;
     313          12 :     args = trigger->tgargs;
     314             : 
     315          12 :     if (nargs < 5)               /* nrefs, action, key, Relation, key - at
     316             :                                  * least */
     317             :         /* internal error */
     318           0 :         elog(ERROR, "check_foreign_key: too short %d (< 5) list of arguments", nargs);
     319             : 
     320          12 :     nrefs = pg_strtoint32(args[0]);
     321          12 :     if (nrefs < 1)
     322             :         /* internal error */
     323           0 :         elog(ERROR, "check_foreign_key: %d (< 1) number of references specified", nrefs);
     324          12 :     action = tolower((unsigned char) *(args[1]));
     325          12 :     if (action != 'r' && action != 'c' && action != 's')
     326             :         /* internal error */
     327           0 :         elog(ERROR, "check_foreign_key: invalid action %s", args[1]);
     328          12 :     nargs -= 2;
     329          12 :     args += 2;
     330          12 :     nkeys = (nargs - nrefs) / (nrefs + 1);
     331          12 :     if (nkeys <= 0 || nargs != (nrefs + nkeys * (nrefs + 1)))
     332             :         /* internal error */
     333           0 :         elog(ERROR, "check_foreign_key: invalid number of arguments %d for %d references",
     334             :              nargs + 2, nrefs);
     335             : 
     336          12 :     rel = trigdata->tg_relation;
     337          12 :     tupdesc = rel->rd_att;
     338             : 
     339             :     /* Connect to SPI manager */
     340          12 :     SPI_connect();
     341             : 
     342             :     /*
     343             :      * We use SPI plan preparation feature, so allocate space to place key
     344             :      * values.
     345             :      */
     346          12 :     kvals = (Datum *) palloc(nkeys * sizeof(Datum));
     347             : 
     348             :     /*
     349             :      * Construct ident string as TriggerName $ TriggeredRelationId $
     350             :      * OperationType and try to find prepared execution plan(s).
     351             :      */
     352          12 :     snprintf(ident, sizeof(ident), "%s$%u$%c", trigger->tgname, rel->rd_id, is_update ? 'U' : 'D');
     353          12 :     plan = find_plan(ident, &FPlans, &nFPlans);
     354             : 
     355             :     /* if there is no plan(s) then allocate argtypes for preparation */
     356          12 :     if (plan->nplans <= 0)
     357           8 :         argtypes = (Oid *) palloc(nkeys * sizeof(Oid));
     358             : 
     359             :     /*
     360             :      * else - check that we have exactly nrefs plan(s) ready
     361             :      */
     362           4 :     else if (plan->nplans != nrefs)
     363             :         /* internal error */
     364           0 :         elog(ERROR, "%s: check_foreign_key: # of plans changed in meantime",
     365             :              trigger->tgname);
     366             : 
     367             :     /* For each column in key ... */
     368          30 :     for (i = 0; i < nkeys; i++)
     369             :     {
     370             :         /* get index of column in tuple */
     371          18 :         int         fnumber = SPI_fnumber(tupdesc, args[i]);
     372             : 
     373             :         /* Bad guys may give us un-existing column in CREATE TRIGGER */
     374          18 :         if (fnumber <= 0)
     375           0 :             ereport(ERROR,
     376             :                     (errcode(ERRCODE_UNDEFINED_COLUMN),
     377             :                      errmsg("there is no attribute \"%s\" in relation \"%s\"",
     378             :                             args[i], SPI_getrelname(rel))));
     379             : 
     380             :         /* Well, get binary (in internal format) value of column */
     381          18 :         kvals[i] = SPI_getbinval(trigtuple, tupdesc, fnumber, &isnull);
     382             : 
     383             :         /*
     384             :          * If it's NULL then nothing to do! DON'T FORGET call SPI_finish ()!
     385             :          * DON'T FORGET return tuple! Executor inserts tuple you're returning!
     386             :          * If you return NULL then nothing will be inserted!
     387             :          */
     388          18 :         if (isnull)
     389             :         {
     390           0 :             SPI_finish();
     391           0 :             return PointerGetDatum((newtuple == NULL) ? trigtuple : newtuple);
     392             :         }
     393             : 
     394             :         /*
     395             :          * If UPDATE then get column value from new tuple being inserted and
     396             :          * compare is this the same as old one. For the moment we use string
     397             :          * presentation of values...
     398             :          */
     399          18 :         if (newtuple != NULL)
     400             :         {
     401           6 :             char       *oldval = SPI_getvalue(trigtuple, tupdesc, fnumber);
     402             :             char       *newval;
     403             : 
     404             :             /* this shouldn't happen! SPI_ERROR_NOOUTFUNC ? */
     405           6 :             if (oldval == NULL)
     406             :                 /* internal error */
     407           0 :                 elog(ERROR, "check_foreign_key: SPI_getvalue returned %s", SPI_result_code_string(SPI_result));
     408           6 :             newval = SPI_getvalue(newtuple, tupdesc, fnumber);
     409           6 :             if (newval == NULL || strcmp(oldval, newval) != 0)
     410           4 :                 isequal = false;
     411             :         }
     412             : 
     413          18 :         if (plan->nplans <= 0)    /* Get typeId of column */
     414          12 :             argtypes[i] = SPI_gettypeid(tupdesc, fnumber);
     415             :     }
     416          12 :     args_temp = args;
     417          12 :     nargs -= nkeys;
     418          12 :     args += nkeys;
     419             : 
     420             :     /*
     421             :      * If we have to prepare plans ...
     422             :      */
     423          12 :     if (plan->nplans <= 0)
     424             :     {
     425             :         SPIPlanPtr  pplan;
     426             :         char        sql[8192];
     427           8 :         char      **args2 = args;
     428             : 
     429           8 :         plan->splan = (SPIPlanPtr *) MemoryContextAlloc(TopMemoryContext,
     430             :                                                         nrefs * sizeof(SPIPlanPtr));
     431             : 
     432          20 :         for (r = 0; r < nrefs; r++)
     433             :         {
     434          12 :             relname = args2[0];
     435             : 
     436             :             /*---------
     437             :              * For 'R'estrict action we construct SELECT query:
     438             :              *
     439             :              *  SELECT 1
     440             :              *  FROM _referencing_relation_
     441             :              *  WHERE Fkey1 = $1 [AND Fkey2 = $2 [...]]
     442             :              *
     443             :              *  to check is tuple referenced or not.
     444             :              *---------
     445             :              */
     446          12 :             if (action == 'r')
     447             : 
     448           4 :                 snprintf(sql, sizeof(sql), "select 1 from %s where ", relname);
     449             : 
     450             :             /*---------
     451             :              * For 'C'ascade action we construct DELETE query
     452             :              *
     453             :              *  DELETE
     454             :              *  FROM _referencing_relation_
     455             :              *  WHERE Fkey1 = $1 [AND Fkey2 = $2 [...]]
     456             :              *
     457             :              * to delete all referencing tuples.
     458             :              *---------
     459             :              */
     460             : 
     461             :             /*
     462             :              * Max : Cascade with UPDATE query i create update query that
     463             :              * updates new key values in referenced tables
     464             :              */
     465             : 
     466             : 
     467           8 :             else if (action == 'c')
     468             :             {
     469           8 :                 if (is_update == 1)
     470             :                 {
     471             :                     int         fn;
     472             :                     char       *nv;
     473             :                     int         k;
     474             : 
     475           4 :                     snprintf(sql, sizeof(sql), "update %s set ", relname);
     476          12 :                     for (k = 1; k <= nkeys; k++)
     477             :                     {
     478           8 :                         int         is_char_type = 0;
     479             :                         char       *type;
     480             : 
     481           8 :                         fn = SPI_fnumber(tupdesc, args_temp[k - 1]);
     482             :                         Assert(fn > 0); /* already checked above */
     483           8 :                         nv = SPI_getvalue(newtuple, tupdesc, fn);
     484           8 :                         type = SPI_gettype(tupdesc, fn);
     485             : 
     486           8 :                         if (strcmp(type, "text") == 0 ||
     487           4 :                             strcmp(type, "varchar") == 0 ||
     488           4 :                             strcmp(type, "char") == 0 ||
     489           4 :                             strcmp(type, "bpchar") == 0 ||
     490           4 :                             strcmp(type, "date") == 0 ||
     491           4 :                             strcmp(type, "timestamp") == 0)
     492           4 :                             is_char_type = 1;
     493             : #ifdef  DEBUG_QUERY
     494             :                         elog(DEBUG4, "check_foreign_key Debug value %s type %s %d",
     495             :                              nv, type, is_char_type);
     496             : #endif
     497             : 
     498             :                         /*
     499             :                          * is_char_type =1 i set ' ' for define a new value
     500             :                          */
     501           8 :                         snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql),
     502             :                                  " %s = %s%s%s %s ",
     503           8 :                                  args2[k], (is_char_type > 0) ? "'" : "",
     504             :                                  nv, (is_char_type > 0) ? "'" : "", (k < nkeys) ? ", " : "");
     505             :                     }
     506           4 :                     strcat(sql, " where ");
     507             :                 }
     508             :                 else
     509             :                     /* DELETE */
     510           4 :                     snprintf(sql, sizeof(sql), "delete from %s where ", relname);
     511             :             }
     512             : 
     513             :             /*
     514             :              * For 'S'etnull action we construct UPDATE query - UPDATE
     515             :              * _referencing_relation_ SET Fkey1 null [, Fkey2 null [...]]
     516             :              * WHERE Fkey1 = $1 [AND Fkey2 = $2 [...]] - to set key columns in
     517             :              * all referencing tuples to NULL.
     518             :              */
     519           0 :             else if (action == 's')
     520             :             {
     521           0 :                 snprintf(sql, sizeof(sql), "update %s set ", relname);
     522           0 :                 for (i = 1; i <= nkeys; i++)
     523             :                 {
     524           0 :                     snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql),
     525             :                              "%s = null%s",
     526           0 :                              args2[i], (i < nkeys) ? ", " : "");
     527             :                 }
     528           0 :                 strcat(sql, " where ");
     529             :             }
     530             : 
     531             :             /* Construct WHERE qual */
     532          32 :             for (i = 1; i <= nkeys; i++)
     533             :             {
     534          20 :                 snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql), "%s = $%d %s",
     535          20 :                          args2[i], i, (i < nkeys) ? "and " : "");
     536             :             }
     537             : 
     538             :             /* Prepare plan for query */
     539          12 :             pplan = SPI_prepare(sql, nkeys, argtypes);
     540          12 :             if (pplan == NULL)
     541             :                 /* internal error */
     542           0 :                 elog(ERROR, "check_foreign_key: SPI_prepare returned %s", SPI_result_code_string(SPI_result));
     543             : 
     544             :             /*
     545             :              * Remember that SPI_prepare places plan in current memory context
     546             :              * - so, we have to save plan in Top memory context for later use.
     547             :              */
     548          12 :             if (SPI_keepplan(pplan))
     549             :                 /* internal error */
     550           0 :                 elog(ERROR, "check_foreign_key: SPI_keepplan failed");
     551             : 
     552          12 :             plan->splan[r] = pplan;
     553             : 
     554          12 :             args2 += nkeys + 1; /* to the next relation */
     555             :         }
     556           8 :         plan->nplans = nrefs;
     557             : #ifdef  DEBUG_QUERY
     558             :         elog(DEBUG4, "check_foreign_key Debug Query is :  %s ", sql);
     559             : #endif
     560             :     }
     561             : 
     562             :     /*
     563             :      * If UPDATE and key is not changed ...
     564             :      */
     565          12 :     if (newtuple != NULL && isequal)
     566             :     {
     567           2 :         SPI_finish();
     568           2 :         return PointerGetDatum(newtuple);
     569             :     }
     570             : 
     571             :     /*
     572             :      * Ok, execute prepared plan(s).
     573             :      */
     574          22 :     for (r = 0; r < nrefs; r++)
     575             :     {
     576             :         /*
     577             :          * For 'R'estrict we may to execute plan for one tuple only, for other
     578             :          * actions - for all tuples.
     579             :          */
     580          16 :         int         tcount = (action == 'r') ? 1 : 0;
     581             : 
     582          16 :         relname = args[0];
     583             : 
     584          16 :         ret = SPI_execp(plan->splan[r], kvals, NULL, tcount);
     585             :         /* we have no NULLs - so we pass   ^^^^  here */
     586             : 
     587          14 :         if (ret < 0)
     588           0 :             ereport(ERROR,
     589             :                     (errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
     590             :                      errmsg("SPI_execp returned %d", ret)));
     591             : 
     592             :         /* If action is 'R'estrict ... */
     593          14 :         if (action == 'r')
     594             :         {
     595             :             /* If there is tuple returned by SELECT then ... */
     596           4 :             if (SPI_processed > 0)
     597           2 :                 ereport(ERROR,
     598             :                         (errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
     599             :                          errmsg("\"%s\": tuple is referenced in \"%s\"",
     600             :                                 trigger->tgname, relname)));
     601             :         }
     602             :         else
     603             :         {
     604             : #ifdef REFINT_VERBOSE
     605             :             const char *operation;
     606             : 
     607          10 :             if (action == 'c')
     608          10 :                 operation = is_update ? "updated" : "deleted";
     609             :             else
     610           0 :                 operation = "set to null";
     611             : 
     612          10 :             elog(NOTICE, "%s: " UINT64_FORMAT " tuple(s) of %s are %s",
     613             :                  trigger->tgname, SPI_processed, relname, operation);
     614             : #endif
     615             :         }
     616          12 :         args += nkeys + 1;      /* to the next relation */
     617             :     }
     618             : 
     619           6 :     SPI_finish();
     620             : 
     621           6 :     return PointerGetDatum((newtuple == NULL) ? trigtuple : newtuple);
     622             : }
     623             : 
     624             : static EPlan *
     625          50 : find_plan(char *ident, EPlan **eplan, int *nplans)
     626             : {
     627             :     EPlan      *newp;
     628             :     int         i;
     629             :     MemoryContext oldcontext;
     630             : 
     631             :     /*
     632             :      * All allocations done for the plans need to happen in a session-safe
     633             :      * context.
     634             :      */
     635          50 :     oldcontext = MemoryContextSwitchTo(TopMemoryContext);
     636             : 
     637          50 :     if (*nplans > 0)
     638             :     {
     639          98 :         for (i = 0; i < *nplans; i++)
     640             :         {
     641          88 :             if (strcmp((*eplan)[i].ident, ident) == 0)
     642          36 :                 break;
     643             :         }
     644          46 :         if (i != *nplans)
     645             :         {
     646          36 :             MemoryContextSwitchTo(oldcontext);
     647          36 :             return (*eplan + i);
     648             :         }
     649          10 :         *eplan = (EPlan *) repalloc(*eplan, (i + 1) * sizeof(EPlan));
     650          10 :         newp = *eplan + i;
     651             :     }
     652             :     else
     653             :     {
     654           4 :         newp = *eplan = (EPlan *) palloc(sizeof(EPlan));
     655           4 :         (*nplans) = i = 0;
     656             :     }
     657             : 
     658          14 :     newp->ident = pstrdup(ident);
     659          14 :     newp->nplans = 0;
     660          14 :     newp->splan = NULL;
     661          14 :     (*nplans)++;
     662             : 
     663          14 :     MemoryContextSwitchTo(oldcontext);
     664          14 :     return newp;
     665             : }

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