LCOV - code coverage report
Current view: top level - src/backend/executor - execParallel.c (source / functions) Hit Total Coverage
Test: PostgreSQL 17devel Lines: 523 590 88.6 %
Date: 2024-03-28 11:11:48 Functions: 20 20 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * execParallel.c
       4             :  *    Support routines for parallel execution.
       5             :  *
       6             :  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  * This file contains routines that are intended to support setting up,
      10             :  * using, and tearing down a ParallelContext from within the PostgreSQL
      11             :  * executor.  The ParallelContext machinery will handle starting the
      12             :  * workers and ensuring that their state generally matches that of the
      13             :  * leader; see src/backend/access/transam/README.parallel for details.
      14             :  * However, we must save and restore relevant executor state, such as
      15             :  * any ParamListInfo associated with the query, buffer/WAL usage info, and
      16             :  * the actual plan to be passed down to the worker.
      17             :  *
      18             :  * IDENTIFICATION
      19             :  *    src/backend/executor/execParallel.c
      20             :  *
      21             :  *-------------------------------------------------------------------------
      22             :  */
      23             : 
      24             : #include "postgres.h"
      25             : 
      26             : #include "executor/execParallel.h"
      27             : #include "executor/executor.h"
      28             : #include "executor/nodeAgg.h"
      29             : #include "executor/nodeAppend.h"
      30             : #include "executor/nodeBitmapHeapscan.h"
      31             : #include "executor/nodeCustom.h"
      32             : #include "executor/nodeForeignscan.h"
      33             : #include "executor/nodeHash.h"
      34             : #include "executor/nodeHashjoin.h"
      35             : #include "executor/nodeIncrementalSort.h"
      36             : #include "executor/nodeIndexonlyscan.h"
      37             : #include "executor/nodeIndexscan.h"
      38             : #include "executor/nodeMemoize.h"
      39             : #include "executor/nodeSeqscan.h"
      40             : #include "executor/nodeSort.h"
      41             : #include "executor/nodeSubplan.h"
      42             : #include "executor/tqueue.h"
      43             : #include "jit/jit.h"
      44             : #include "nodes/nodeFuncs.h"
      45             : #include "pgstat.h"
      46             : #include "tcop/tcopprot.h"
      47             : #include "utils/datum.h"
      48             : #include "utils/dsa.h"
      49             : #include "utils/lsyscache.h"
      50             : #include "utils/snapmgr.h"
      51             : 
      52             : /*
      53             :  * Magic numbers for parallel executor communication.  We use constants
      54             :  * greater than any 32-bit integer here so that values < 2^32 can be used
      55             :  * by individual parallel nodes to store their own state.
      56             :  */
      57             : #define PARALLEL_KEY_EXECUTOR_FIXED     UINT64CONST(0xE000000000000001)
      58             : #define PARALLEL_KEY_PLANNEDSTMT        UINT64CONST(0xE000000000000002)
      59             : #define PARALLEL_KEY_PARAMLISTINFO      UINT64CONST(0xE000000000000003)
      60             : #define PARALLEL_KEY_BUFFER_USAGE       UINT64CONST(0xE000000000000004)
      61             : #define PARALLEL_KEY_TUPLE_QUEUE        UINT64CONST(0xE000000000000005)
      62             : #define PARALLEL_KEY_INSTRUMENTATION    UINT64CONST(0xE000000000000006)
      63             : #define PARALLEL_KEY_DSA                UINT64CONST(0xE000000000000007)
      64             : #define PARALLEL_KEY_QUERY_TEXT     UINT64CONST(0xE000000000000008)
      65             : #define PARALLEL_KEY_JIT_INSTRUMENTATION UINT64CONST(0xE000000000000009)
      66             : #define PARALLEL_KEY_WAL_USAGE          UINT64CONST(0xE00000000000000A)
      67             : 
      68             : #define PARALLEL_TUPLE_QUEUE_SIZE       65536
      69             : 
      70             : /*
      71             :  * Fixed-size random stuff that we need to pass to parallel workers.
      72             :  */
      73             : typedef struct FixedParallelExecutorState
      74             : {
      75             :     int64       tuples_needed;  /* tuple bound, see ExecSetTupleBound */
      76             :     dsa_pointer param_exec;
      77             :     int         eflags;
      78             :     int         jit_flags;
      79             : } FixedParallelExecutorState;
      80             : 
      81             : /*
      82             :  * DSM structure for accumulating per-PlanState instrumentation.
      83             :  *
      84             :  * instrument_options: Same meaning here as in instrument.c.
      85             :  *
      86             :  * instrument_offset: Offset, relative to the start of this structure,
      87             :  * of the first Instrumentation object.  This will depend on the length of
      88             :  * the plan_node_id array.
      89             :  *
      90             :  * num_workers: Number of workers.
      91             :  *
      92             :  * num_plan_nodes: Number of plan nodes.
      93             :  *
      94             :  * plan_node_id: Array of plan nodes for which we are gathering instrumentation
      95             :  * from parallel workers.  The length of this array is given by num_plan_nodes.
      96             :  */
      97             : struct SharedExecutorInstrumentation
      98             : {
      99             :     int         instrument_options;
     100             :     int         instrument_offset;
     101             :     int         num_workers;
     102             :     int         num_plan_nodes;
     103             :     int         plan_node_id[FLEXIBLE_ARRAY_MEMBER];
     104             :     /* array of num_plan_nodes * num_workers Instrumentation objects follows */
     105             : };
     106             : #define GetInstrumentationArray(sei) \
     107             :     (AssertVariableIsOfTypeMacro(sei, SharedExecutorInstrumentation *), \
     108             :      (Instrumentation *) (((char *) sei) + sei->instrument_offset))
     109             : 
     110             : /* Context object for ExecParallelEstimate. */
     111             : typedef struct ExecParallelEstimateContext
     112             : {
     113             :     ParallelContext *pcxt;
     114             :     int         nnodes;
     115             : } ExecParallelEstimateContext;
     116             : 
     117             : /* Context object for ExecParallelInitializeDSM. */
     118             : typedef struct ExecParallelInitializeDSMContext
     119             : {
     120             :     ParallelContext *pcxt;
     121             :     SharedExecutorInstrumentation *instrumentation;
     122             :     int         nnodes;
     123             : } ExecParallelInitializeDSMContext;
     124             : 
     125             : /* Helper functions that run in the parallel leader. */
     126             : static char *ExecSerializePlan(Plan *plan, EState *estate);
     127             : static bool ExecParallelEstimate(PlanState *planstate,
     128             :                                  ExecParallelEstimateContext *e);
     129             : static bool ExecParallelInitializeDSM(PlanState *planstate,
     130             :                                       ExecParallelInitializeDSMContext *d);
     131             : static shm_mq_handle **ExecParallelSetupTupleQueues(ParallelContext *pcxt,
     132             :                                                     bool reinitialize);
     133             : static bool ExecParallelReInitializeDSM(PlanState *planstate,
     134             :                                         ParallelContext *pcxt);
     135             : static bool ExecParallelRetrieveInstrumentation(PlanState *planstate,
     136             :                                                 SharedExecutorInstrumentation *instrumentation);
     137             : 
     138             : /* Helper function that runs in the parallel worker. */
     139             : static DestReceiver *ExecParallelGetReceiver(dsm_segment *seg, shm_toc *toc);
     140             : 
     141             : /*
     142             :  * Create a serialized representation of the plan to be sent to each worker.
     143             :  */
     144             : static char *
     145         652 : ExecSerializePlan(Plan *plan, EState *estate)
     146             : {
     147             :     PlannedStmt *pstmt;
     148             :     ListCell   *lc;
     149             : 
     150             :     /* We can't scribble on the original plan, so make a copy. */
     151         652 :     plan = copyObject(plan);
     152             : 
     153             :     /*
     154             :      * The worker will start its own copy of the executor, and that copy will
     155             :      * insert a junk filter if the toplevel node has any resjunk entries. We
     156             :      * don't want that to happen, because while resjunk columns shouldn't be
     157             :      * sent back to the user, here the tuples are coming back to another
     158             :      * backend which may very well need them.  So mutate the target list
     159             :      * accordingly.  This is sort of a hack; there might be better ways to do
     160             :      * this...
     161             :      */
     162        1806 :     foreach(lc, plan->targetlist)
     163             :     {
     164        1154 :         TargetEntry *tle = lfirst_node(TargetEntry, lc);
     165             : 
     166        1154 :         tle->resjunk = false;
     167             :     }
     168             : 
     169             :     /*
     170             :      * Create a dummy PlannedStmt.  Most of the fields don't need to be valid
     171             :      * for our purposes, but the worker will need at least a minimal
     172             :      * PlannedStmt to start the executor.
     173             :      */
     174         652 :     pstmt = makeNode(PlannedStmt);
     175         652 :     pstmt->commandType = CMD_SELECT;
     176         652 :     pstmt->queryId = pgstat_get_my_query_id();
     177         652 :     pstmt->hasReturning = false;
     178         652 :     pstmt->hasModifyingCTE = false;
     179         652 :     pstmt->canSetTag = true;
     180         652 :     pstmt->transientPlan = false;
     181         652 :     pstmt->dependsOnRole = false;
     182         652 :     pstmt->parallelModeNeeded = false;
     183         652 :     pstmt->planTree = plan;
     184         652 :     pstmt->rtable = estate->es_range_table;
     185         652 :     pstmt->permInfos = estate->es_rteperminfos;
     186         652 :     pstmt->resultRelations = NIL;
     187         652 :     pstmt->appendRelations = NIL;
     188             : 
     189             :     /*
     190             :      * Transfer only parallel-safe subplans, leaving a NULL "hole" in the list
     191             :      * for unsafe ones (so that the list indexes of the safe ones are
     192             :      * preserved).  This positively ensures that the worker won't try to run,
     193             :      * or even do ExecInitNode on, an unsafe subplan.  That's important to
     194             :      * protect, eg, non-parallel-aware FDWs from getting into trouble.
     195             :      */
     196         652 :     pstmt->subplans = NIL;
     197         700 :     foreach(lc, estate->es_plannedstmt->subplans)
     198             :     {
     199          48 :         Plan       *subplan = (Plan *) lfirst(lc);
     200             : 
     201          48 :         if (subplan && !subplan->parallel_safe)
     202          12 :             subplan = NULL;
     203          48 :         pstmt->subplans = lappend(pstmt->subplans, subplan);
     204             :     }
     205             : 
     206         652 :     pstmt->rewindPlanIDs = NULL;
     207         652 :     pstmt->rowMarks = NIL;
     208         652 :     pstmt->relationOids = NIL;
     209         652 :     pstmt->invalItems = NIL; /* workers can't replan anyway... */
     210         652 :     pstmt->paramExecTypes = estate->es_plannedstmt->paramExecTypes;
     211         652 :     pstmt->utilityStmt = NULL;
     212         652 :     pstmt->stmt_location = -1;
     213         652 :     pstmt->stmt_len = -1;
     214             : 
     215             :     /* Return serialized copy of our dummy PlannedStmt. */
     216         652 :     return nodeToString(pstmt);
     217             : }
     218             : 
     219             : /*
     220             :  * Parallel-aware plan nodes (and occasionally others) may need some state
     221             :  * which is shared across all parallel workers.  Before we size the DSM, give
     222             :  * them a chance to call shm_toc_estimate_chunk or shm_toc_estimate_keys on
     223             :  * &pcxt->estimator.
     224             :  *
     225             :  * While we're at it, count the number of PlanState nodes in the tree, so
     226             :  * we know how many Instrumentation structures we need.
     227             :  */
     228             : static bool
     229        2924 : ExecParallelEstimate(PlanState *planstate, ExecParallelEstimateContext *e)
     230             : {
     231        2924 :     if (planstate == NULL)
     232           0 :         return false;
     233             : 
     234             :     /* Count this node. */
     235        2924 :     e->nnodes++;
     236             : 
     237        2924 :     switch (nodeTag(planstate))
     238             :     {
     239        1136 :         case T_SeqScanState:
     240        1136 :             if (planstate->plan->parallel_aware)
     241         898 :                 ExecSeqScanEstimate((SeqScanState *) planstate,
     242             :                                     e->pcxt);
     243        1136 :             break;
     244         302 :         case T_IndexScanState:
     245         302 :             if (planstate->plan->parallel_aware)
     246          12 :                 ExecIndexScanEstimate((IndexScanState *) planstate,
     247             :                                       e->pcxt);
     248         302 :             break;
     249          52 :         case T_IndexOnlyScanState:
     250          52 :             if (planstate->plan->parallel_aware)
     251          40 :                 ExecIndexOnlyScanEstimate((IndexOnlyScanState *) planstate,
     252             :                                           e->pcxt);
     253          52 :             break;
     254           0 :         case T_ForeignScanState:
     255           0 :             if (planstate->plan->parallel_aware)
     256           0 :                 ExecForeignScanEstimate((ForeignScanState *) planstate,
     257             :                                         e->pcxt);
     258           0 :             break;
     259         186 :         case T_AppendState:
     260         186 :             if (planstate->plan->parallel_aware)
     261         138 :                 ExecAppendEstimate((AppendState *) planstate,
     262             :                                    e->pcxt);
     263         186 :             break;
     264           0 :         case T_CustomScanState:
     265           0 :             if (planstate->plan->parallel_aware)
     266           0 :                 ExecCustomScanEstimate((CustomScanState *) planstate,
     267             :                                        e->pcxt);
     268           0 :             break;
     269          22 :         case T_BitmapHeapScanState:
     270          22 :             if (planstate->plan->parallel_aware)
     271          20 :                 ExecBitmapHeapEstimate((BitmapHeapScanState *) planstate,
     272             :                                        e->pcxt);
     273          22 :             break;
     274         192 :         case T_HashJoinState:
     275         192 :             if (planstate->plan->parallel_aware)
     276         120 :                 ExecHashJoinEstimate((HashJoinState *) planstate,
     277             :                                      e->pcxt);
     278         192 :             break;
     279         192 :         case T_HashState:
     280             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     281         192 :             ExecHashEstimate((HashState *) planstate, e->pcxt);
     282         192 :             break;
     283         154 :         case T_SortState:
     284             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     285         154 :             ExecSortEstimate((SortState *) planstate, e->pcxt);
     286         154 :             break;
     287           0 :         case T_IncrementalSortState:
     288             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     289           0 :             ExecIncrementalSortEstimate((IncrementalSortState *) planstate, e->pcxt);
     290           0 :             break;
     291         558 :         case T_AggState:
     292             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     293         558 :             ExecAggEstimate((AggState *) planstate, e->pcxt);
     294         558 :             break;
     295           6 :         case T_MemoizeState:
     296             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     297           6 :             ExecMemoizeEstimate((MemoizeState *) planstate, e->pcxt);
     298           6 :             break;
     299         124 :         default:
     300         124 :             break;
     301             :     }
     302             : 
     303        2924 :     return planstate_tree_walker(planstate, ExecParallelEstimate, e);
     304             : }
     305             : 
     306             : /*
     307             :  * Estimate the amount of space required to serialize the indicated parameters.
     308             :  */
     309             : static Size
     310          18 : EstimateParamExecSpace(EState *estate, Bitmapset *params)
     311             : {
     312             :     int         paramid;
     313          18 :     Size        sz = sizeof(int);
     314             : 
     315          18 :     paramid = -1;
     316          42 :     while ((paramid = bms_next_member(params, paramid)) >= 0)
     317             :     {
     318             :         Oid         typeOid;
     319             :         int16       typLen;
     320             :         bool        typByVal;
     321             :         ParamExecData *prm;
     322             : 
     323          24 :         prm = &(estate->es_param_exec_vals[paramid]);
     324          24 :         typeOid = list_nth_oid(estate->es_plannedstmt->paramExecTypes,
     325             :                                paramid);
     326             : 
     327          24 :         sz = add_size(sz, sizeof(int)); /* space for paramid */
     328             : 
     329             :         /* space for datum/isnull */
     330          24 :         if (OidIsValid(typeOid))
     331          24 :             get_typlenbyval(typeOid, &typLen, &typByVal);
     332             :         else
     333             :         {
     334             :             /* If no type OID, assume by-value, like copyParamList does. */
     335           0 :             typLen = sizeof(Datum);
     336           0 :             typByVal = true;
     337             :         }
     338          24 :         sz = add_size(sz,
     339          24 :                       datumEstimateSpace(prm->value, prm->isnull,
     340             :                                          typByVal, typLen));
     341             :     }
     342          18 :     return sz;
     343             : }
     344             : 
     345             : /*
     346             :  * Serialize specified PARAM_EXEC parameters.
     347             :  *
     348             :  * We write the number of parameters first, as a 4-byte integer, and then
     349             :  * write details for each parameter in turn.  The details for each parameter
     350             :  * consist of a 4-byte paramid (location of param in execution time internal
     351             :  * parameter array) and then the datum as serialized by datumSerialize().
     352             :  */
     353             : static dsa_pointer
     354          18 : SerializeParamExecParams(EState *estate, Bitmapset *params, dsa_area *area)
     355             : {
     356             :     Size        size;
     357             :     int         nparams;
     358             :     int         paramid;
     359             :     ParamExecData *prm;
     360             :     dsa_pointer handle;
     361             :     char       *start_address;
     362             : 
     363             :     /* Allocate enough space for the current parameter values. */
     364          18 :     size = EstimateParamExecSpace(estate, params);
     365          18 :     handle = dsa_allocate(area, size);
     366          18 :     start_address = dsa_get_address(area, handle);
     367             : 
     368             :     /* First write the number of parameters as a 4-byte integer. */
     369          18 :     nparams = bms_num_members(params);
     370          18 :     memcpy(start_address, &nparams, sizeof(int));
     371          18 :     start_address += sizeof(int);
     372             : 
     373             :     /* Write details for each parameter in turn. */
     374          18 :     paramid = -1;
     375          42 :     while ((paramid = bms_next_member(params, paramid)) >= 0)
     376             :     {
     377             :         Oid         typeOid;
     378             :         int16       typLen;
     379             :         bool        typByVal;
     380             : 
     381          24 :         prm = &(estate->es_param_exec_vals[paramid]);
     382          24 :         typeOid = list_nth_oid(estate->es_plannedstmt->paramExecTypes,
     383             :                                paramid);
     384             : 
     385             :         /* Write paramid. */
     386          24 :         memcpy(start_address, &paramid, sizeof(int));
     387          24 :         start_address += sizeof(int);
     388             : 
     389             :         /* Write datum/isnull */
     390          24 :         if (OidIsValid(typeOid))
     391          24 :             get_typlenbyval(typeOid, &typLen, &typByVal);
     392             :         else
     393             :         {
     394             :             /* If no type OID, assume by-value, like copyParamList does. */
     395           0 :             typLen = sizeof(Datum);
     396           0 :             typByVal = true;
     397             :         }
     398          24 :         datumSerialize(prm->value, prm->isnull, typByVal, typLen,
     399             :                        &start_address);
     400             :     }
     401             : 
     402          18 :     return handle;
     403             : }
     404             : 
     405             : /*
     406             :  * Restore specified PARAM_EXEC parameters.
     407             :  */
     408             : static void
     409          48 : RestoreParamExecParams(char *start_address, EState *estate)
     410             : {
     411             :     int         nparams;
     412             :     int         i;
     413             :     int         paramid;
     414             : 
     415          48 :     memcpy(&nparams, start_address, sizeof(int));
     416          48 :     start_address += sizeof(int);
     417             : 
     418         108 :     for (i = 0; i < nparams; i++)
     419             :     {
     420             :         ParamExecData *prm;
     421             : 
     422             :         /* Read paramid */
     423          60 :         memcpy(&paramid, start_address, sizeof(int));
     424          60 :         start_address += sizeof(int);
     425          60 :         prm = &(estate->es_param_exec_vals[paramid]);
     426             : 
     427             :         /* Read datum/isnull. */
     428          60 :         prm->value = datumRestore(&start_address, &prm->isnull);
     429          60 :         prm->execPlan = NULL;
     430             :     }
     431          48 : }
     432             : 
     433             : /*
     434             :  * Initialize the dynamic shared memory segment that will be used to control
     435             :  * parallel execution.
     436             :  */
     437             : static bool
     438        2924 : ExecParallelInitializeDSM(PlanState *planstate,
     439             :                           ExecParallelInitializeDSMContext *d)
     440             : {
     441        2924 :     if (planstate == NULL)
     442           0 :         return false;
     443             : 
     444             :     /* If instrumentation is enabled, initialize slot for this node. */
     445        2924 :     if (d->instrumentation != NULL)
     446        1032 :         d->instrumentation->plan_node_id[d->nnodes] =
     447        1032 :             planstate->plan->plan_node_id;
     448             : 
     449             :     /* Count this node. */
     450        2924 :     d->nnodes++;
     451             : 
     452             :     /*
     453             :      * Call initializers for DSM-using plan nodes.
     454             :      *
     455             :      * Most plan nodes won't do anything here, but plan nodes that allocated
     456             :      * DSM may need to initialize shared state in the DSM before parallel
     457             :      * workers are launched.  They can allocate the space they previously
     458             :      * estimated using shm_toc_allocate, and add the keys they previously
     459             :      * estimated using shm_toc_insert, in each case targeting pcxt->toc.
     460             :      */
     461        2924 :     switch (nodeTag(planstate))
     462             :     {
     463        1136 :         case T_SeqScanState:
     464        1136 :             if (planstate->plan->parallel_aware)
     465         898 :                 ExecSeqScanInitializeDSM((SeqScanState *) planstate,
     466             :                                          d->pcxt);
     467        1136 :             break;
     468         302 :         case T_IndexScanState:
     469         302 :             if (planstate->plan->parallel_aware)
     470          12 :                 ExecIndexScanInitializeDSM((IndexScanState *) planstate,
     471             :                                            d->pcxt);
     472         302 :             break;
     473          52 :         case T_IndexOnlyScanState:
     474          52 :             if (planstate->plan->parallel_aware)
     475          40 :                 ExecIndexOnlyScanInitializeDSM((IndexOnlyScanState *) planstate,
     476             :                                                d->pcxt);
     477          52 :             break;
     478           0 :         case T_ForeignScanState:
     479           0 :             if (planstate->plan->parallel_aware)
     480           0 :                 ExecForeignScanInitializeDSM((ForeignScanState *) planstate,
     481             :                                              d->pcxt);
     482           0 :             break;
     483         186 :         case T_AppendState:
     484         186 :             if (planstate->plan->parallel_aware)
     485         138 :                 ExecAppendInitializeDSM((AppendState *) planstate,
     486             :                                         d->pcxt);
     487         186 :             break;
     488           0 :         case T_CustomScanState:
     489           0 :             if (planstate->plan->parallel_aware)
     490           0 :                 ExecCustomScanInitializeDSM((CustomScanState *) planstate,
     491             :                                             d->pcxt);
     492           0 :             break;
     493          22 :         case T_BitmapHeapScanState:
     494          22 :             if (planstate->plan->parallel_aware)
     495          20 :                 ExecBitmapHeapInitializeDSM((BitmapHeapScanState *) planstate,
     496             :                                             d->pcxt);
     497          22 :             break;
     498         192 :         case T_HashJoinState:
     499         192 :             if (planstate->plan->parallel_aware)
     500         120 :                 ExecHashJoinInitializeDSM((HashJoinState *) planstate,
     501             :                                           d->pcxt);
     502         192 :             break;
     503         192 :         case T_HashState:
     504             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     505         192 :             ExecHashInitializeDSM((HashState *) planstate, d->pcxt);
     506         192 :             break;
     507         154 :         case T_SortState:
     508             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     509         154 :             ExecSortInitializeDSM((SortState *) planstate, d->pcxt);
     510         154 :             break;
     511           0 :         case T_IncrementalSortState:
     512             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     513           0 :             ExecIncrementalSortInitializeDSM((IncrementalSortState *) planstate, d->pcxt);
     514           0 :             break;
     515         558 :         case T_AggState:
     516             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     517         558 :             ExecAggInitializeDSM((AggState *) planstate, d->pcxt);
     518         558 :             break;
     519           6 :         case T_MemoizeState:
     520             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
     521           6 :             ExecMemoizeInitializeDSM((MemoizeState *) planstate, d->pcxt);
     522           6 :             break;
     523         124 :         default:
     524         124 :             break;
     525             :     }
     526             : 
     527        2924 :     return planstate_tree_walker(planstate, ExecParallelInitializeDSM, d);
     528             : }
     529             : 
     530             : /*
     531             :  * It sets up the response queues for backend workers to return tuples
     532             :  * to the main backend and start the workers.
     533             :  */
     534             : static shm_mq_handle **
     535         910 : ExecParallelSetupTupleQueues(ParallelContext *pcxt, bool reinitialize)
     536             : {
     537             :     shm_mq_handle **responseq;
     538             :     char       *tqueuespace;
     539             :     int         i;
     540             : 
     541             :     /* Skip this if no workers. */
     542         910 :     if (pcxt->nworkers == 0)
     543           0 :         return NULL;
     544             : 
     545             :     /* Allocate memory for shared memory queue handles. */
     546             :     responseq = (shm_mq_handle **)
     547         910 :         palloc(pcxt->nworkers * sizeof(shm_mq_handle *));
     548             : 
     549             :     /*
     550             :      * If not reinitializing, allocate space from the DSM for the queues;
     551             :      * otherwise, find the already allocated space.
     552             :      */
     553         910 :     if (!reinitialize)
     554             :         tqueuespace =
     555         652 :             shm_toc_allocate(pcxt->toc,
     556             :                              mul_size(PARALLEL_TUPLE_QUEUE_SIZE,
     557         652 :                                       pcxt->nworkers));
     558             :     else
     559         258 :         tqueuespace = shm_toc_lookup(pcxt->toc, PARALLEL_KEY_TUPLE_QUEUE, false);
     560             : 
     561             :     /* Create the queues, and become the receiver for each. */
     562        3416 :     for (i = 0; i < pcxt->nworkers; ++i)
     563             :     {
     564             :         shm_mq     *mq;
     565             : 
     566        2506 :         mq = shm_mq_create(tqueuespace +
     567        2506 :                            ((Size) i) * PARALLEL_TUPLE_QUEUE_SIZE,
     568             :                            (Size) PARALLEL_TUPLE_QUEUE_SIZE);
     569             : 
     570        2506 :         shm_mq_set_receiver(mq, MyProc);
     571        2506 :         responseq[i] = shm_mq_attach(mq, pcxt->seg, NULL);
     572             :     }
     573             : 
     574             :     /* Add array of queues to shm_toc, so others can find it. */
     575         910 :     if (!reinitialize)
     576         652 :         shm_toc_insert(pcxt->toc, PARALLEL_KEY_TUPLE_QUEUE, tqueuespace);
     577             : 
     578             :     /* Return array of handles. */
     579         910 :     return responseq;
     580             : }
     581             : 
     582             : /*
     583             :  * Sets up the required infrastructure for backend workers to perform
     584             :  * execution and return results to the main backend.
     585             :  */
     586             : ParallelExecutorInfo *
     587         652 : ExecInitParallelPlan(PlanState *planstate, EState *estate,
     588             :                      Bitmapset *sendParams, int nworkers,
     589             :                      int64 tuples_needed)
     590             : {
     591             :     ParallelExecutorInfo *pei;
     592             :     ParallelContext *pcxt;
     593             :     ExecParallelEstimateContext e;
     594             :     ExecParallelInitializeDSMContext d;
     595             :     FixedParallelExecutorState *fpes;
     596             :     char       *pstmt_data;
     597             :     char       *pstmt_space;
     598             :     char       *paramlistinfo_space;
     599             :     BufferUsage *bufusage_space;
     600             :     WalUsage   *walusage_space;
     601         652 :     SharedExecutorInstrumentation *instrumentation = NULL;
     602         652 :     SharedJitInstrumentation *jit_instrumentation = NULL;
     603             :     int         pstmt_len;
     604             :     int         paramlistinfo_len;
     605         652 :     int         instrumentation_len = 0;
     606         652 :     int         jit_instrumentation_len = 0;
     607         652 :     int         instrument_offset = 0;
     608         652 :     Size        dsa_minsize = dsa_minimum_size();
     609             :     char       *query_string;
     610             :     int         query_len;
     611             : 
     612             :     /*
     613             :      * Force any initplan outputs that we're going to pass to workers to be
     614             :      * evaluated, if they weren't already.
     615             :      *
     616             :      * For simplicity, we use the EState's per-output-tuple ExprContext here.
     617             :      * That risks intra-query memory leakage, since we might pass through here
     618             :      * many times before that ExprContext gets reset; but ExecSetParamPlan
     619             :      * doesn't normally leak any memory in the context (see its comments), so
     620             :      * it doesn't seem worth complicating this function's API to pass it a
     621             :      * shorter-lived ExprContext.  This might need to change someday.
     622             :      */
     623         652 :     ExecSetParamPlanMulti(sendParams, GetPerTupleExprContext(estate));
     624             : 
     625             :     /* Allocate object for return value. */
     626         652 :     pei = palloc0(sizeof(ParallelExecutorInfo));
     627         652 :     pei->finished = false;
     628         652 :     pei->planstate = planstate;
     629             : 
     630             :     /* Fix up and serialize plan to be sent to workers. */
     631         652 :     pstmt_data = ExecSerializePlan(planstate->plan, estate);
     632             : 
     633             :     /* Create a parallel context. */
     634         652 :     pcxt = CreateParallelContext("postgres", "ParallelQueryMain", nworkers);
     635         652 :     pei->pcxt = pcxt;
     636             : 
     637             :     /*
     638             :      * Before telling the parallel context to create a dynamic shared memory
     639             :      * segment, we need to figure out how big it should be.  Estimate space
     640             :      * for the various things we need to store.
     641             :      */
     642             : 
     643             :     /* Estimate space for fixed-size state. */
     644         652 :     shm_toc_estimate_chunk(&pcxt->estimator,
     645             :                            sizeof(FixedParallelExecutorState));
     646         652 :     shm_toc_estimate_keys(&pcxt->estimator, 1);
     647             : 
     648             :     /* Estimate space for query text. */
     649         652 :     query_len = strlen(estate->es_sourceText);
     650         652 :     shm_toc_estimate_chunk(&pcxt->estimator, query_len + 1);
     651         652 :     shm_toc_estimate_keys(&pcxt->estimator, 1);
     652             : 
     653             :     /* Estimate space for serialized PlannedStmt. */
     654         652 :     pstmt_len = strlen(pstmt_data) + 1;
     655         652 :     shm_toc_estimate_chunk(&pcxt->estimator, pstmt_len);
     656         652 :     shm_toc_estimate_keys(&pcxt->estimator, 1);
     657             : 
     658             :     /* Estimate space for serialized ParamListInfo. */
     659         652 :     paramlistinfo_len = EstimateParamListSpace(estate->es_param_list_info);
     660         652 :     shm_toc_estimate_chunk(&pcxt->estimator, paramlistinfo_len);
     661         652 :     shm_toc_estimate_keys(&pcxt->estimator, 1);
     662             : 
     663             :     /*
     664             :      * Estimate space for BufferUsage.
     665             :      *
     666             :      * If EXPLAIN is not in use and there are no extensions loaded that care,
     667             :      * we could skip this.  But we have no way of knowing whether anyone's
     668             :      * looking at pgBufferUsage, so do it unconditionally.
     669             :      */
     670         652 :     shm_toc_estimate_chunk(&pcxt->estimator,
     671             :                            mul_size(sizeof(BufferUsage), pcxt->nworkers));
     672         652 :     shm_toc_estimate_keys(&pcxt->estimator, 1);
     673             : 
     674             :     /*
     675             :      * Same thing for WalUsage.
     676             :      */
     677         652 :     shm_toc_estimate_chunk(&pcxt->estimator,
     678             :                            mul_size(sizeof(WalUsage), pcxt->nworkers));
     679         652 :     shm_toc_estimate_keys(&pcxt->estimator, 1);
     680             : 
     681             :     /* Estimate space for tuple queues. */
     682         652 :     shm_toc_estimate_chunk(&pcxt->estimator,
     683             :                            mul_size(PARALLEL_TUPLE_QUEUE_SIZE, pcxt->nworkers));
     684         652 :     shm_toc_estimate_keys(&pcxt->estimator, 1);
     685             : 
     686             :     /*
     687             :      * Give parallel-aware nodes a chance to add to the estimates, and get a
     688             :      * count of how many PlanState nodes there are.
     689             :      */
     690         652 :     e.pcxt = pcxt;
     691         652 :     e.nnodes = 0;
     692         652 :     ExecParallelEstimate(planstate, &e);
     693             : 
     694             :     /* Estimate space for instrumentation, if required. */
     695         652 :     if (estate->es_instrument)
     696             :     {
     697         180 :         instrumentation_len =
     698             :             offsetof(SharedExecutorInstrumentation, plan_node_id) +
     699         180 :             sizeof(int) * e.nnodes;
     700         180 :         instrumentation_len = MAXALIGN(instrumentation_len);
     701         180 :         instrument_offset = instrumentation_len;
     702         180 :         instrumentation_len +=
     703         180 :             mul_size(sizeof(Instrumentation),
     704         180 :                      mul_size(e.nnodes, nworkers));
     705         180 :         shm_toc_estimate_chunk(&pcxt->estimator, instrumentation_len);
     706         180 :         shm_toc_estimate_keys(&pcxt->estimator, 1);
     707             : 
     708             :         /* Estimate space for JIT instrumentation, if required. */
     709         180 :         if (estate->es_jit_flags != PGJIT_NONE)
     710             :         {
     711          24 :             jit_instrumentation_len =
     712          24 :                 offsetof(SharedJitInstrumentation, jit_instr) +
     713             :                 sizeof(JitInstrumentation) * nworkers;
     714          24 :             shm_toc_estimate_chunk(&pcxt->estimator, jit_instrumentation_len);
     715          24 :             shm_toc_estimate_keys(&pcxt->estimator, 1);
     716             :         }
     717             :     }
     718             : 
     719             :     /* Estimate space for DSA area. */
     720         652 :     shm_toc_estimate_chunk(&pcxt->estimator, dsa_minsize);
     721         652 :     shm_toc_estimate_keys(&pcxt->estimator, 1);
     722             : 
     723             :     /*
     724             :      * InitializeParallelDSM() passes the active snapshot to the parallel
     725             :      * worker, which uses it to set es_snapshot.  Make sure we don't set
     726             :      * es_snapshot differently in the child.
     727             :      */
     728             :     Assert(GetActiveSnapshot() == estate->es_snapshot);
     729             : 
     730             :     /* Everyone's had a chance to ask for space, so now create the DSM. */
     731         652 :     InitializeParallelDSM(pcxt);
     732             : 
     733             :     /*
     734             :      * OK, now we have a dynamic shared memory segment, and it should be big
     735             :      * enough to store all of the data we estimated we would want to put into
     736             :      * it, plus whatever general stuff (not specifically executor-related) the
     737             :      * ParallelContext itself needs to store there.  None of the space we
     738             :      * asked for has been allocated or initialized yet, though, so do that.
     739             :      */
     740             : 
     741             :     /* Store fixed-size state. */
     742         652 :     fpes = shm_toc_allocate(pcxt->toc, sizeof(FixedParallelExecutorState));
     743         652 :     fpes->tuples_needed = tuples_needed;
     744         652 :     fpes->param_exec = InvalidDsaPointer;
     745         652 :     fpes->eflags = estate->es_top_eflags;
     746         652 :     fpes->jit_flags = estate->es_jit_flags;
     747         652 :     shm_toc_insert(pcxt->toc, PARALLEL_KEY_EXECUTOR_FIXED, fpes);
     748             : 
     749             :     /* Store query string */
     750         652 :     query_string = shm_toc_allocate(pcxt->toc, query_len + 1);
     751         652 :     memcpy(query_string, estate->es_sourceText, query_len + 1);
     752         652 :     shm_toc_insert(pcxt->toc, PARALLEL_KEY_QUERY_TEXT, query_string);
     753             : 
     754             :     /* Store serialized PlannedStmt. */
     755         652 :     pstmt_space = shm_toc_allocate(pcxt->toc, pstmt_len);
     756         652 :     memcpy(pstmt_space, pstmt_data, pstmt_len);
     757         652 :     shm_toc_insert(pcxt->toc, PARALLEL_KEY_PLANNEDSTMT, pstmt_space);
     758             : 
     759             :     /* Store serialized ParamListInfo. */
     760         652 :     paramlistinfo_space = shm_toc_allocate(pcxt->toc, paramlistinfo_len);
     761         652 :     shm_toc_insert(pcxt->toc, PARALLEL_KEY_PARAMLISTINFO, paramlistinfo_space);
     762         652 :     SerializeParamList(estate->es_param_list_info, &paramlistinfo_space);
     763             : 
     764             :     /* Allocate space for each worker's BufferUsage; no need to initialize. */
     765         652 :     bufusage_space = shm_toc_allocate(pcxt->toc,
     766         652 :                                       mul_size(sizeof(BufferUsage), pcxt->nworkers));
     767         652 :     shm_toc_insert(pcxt->toc, PARALLEL_KEY_BUFFER_USAGE, bufusage_space);
     768         652 :     pei->buffer_usage = bufusage_space;
     769             : 
     770             :     /* Same for WalUsage. */
     771         652 :     walusage_space = shm_toc_allocate(pcxt->toc,
     772         652 :                                       mul_size(sizeof(WalUsage), pcxt->nworkers));
     773         652 :     shm_toc_insert(pcxt->toc, PARALLEL_KEY_WAL_USAGE, walusage_space);
     774         652 :     pei->wal_usage = walusage_space;
     775             : 
     776             :     /* Set up the tuple queues that the workers will write into. */
     777         652 :     pei->tqueue = ExecParallelSetupTupleQueues(pcxt, false);
     778             : 
     779             :     /* We don't need the TupleQueueReaders yet, though. */
     780         652 :     pei->reader = NULL;
     781             : 
     782             :     /*
     783             :      * If instrumentation options were supplied, allocate space for the data.
     784             :      * It only gets partially initialized here; the rest happens during
     785             :      * ExecParallelInitializeDSM.
     786             :      */
     787         652 :     if (estate->es_instrument)
     788             :     {
     789             :         Instrumentation *instrument;
     790             :         int         i;
     791             : 
     792         180 :         instrumentation = shm_toc_allocate(pcxt->toc, instrumentation_len);
     793         180 :         instrumentation->instrument_options = estate->es_instrument;
     794         180 :         instrumentation->instrument_offset = instrument_offset;
     795         180 :         instrumentation->num_workers = nworkers;
     796         180 :         instrumentation->num_plan_nodes = e.nnodes;
     797         180 :         instrument = GetInstrumentationArray(instrumentation);
     798        1866 :         for (i = 0; i < nworkers * e.nnodes; ++i)
     799        1686 :             InstrInit(&instrument[i], estate->es_instrument);
     800         180 :         shm_toc_insert(pcxt->toc, PARALLEL_KEY_INSTRUMENTATION,
     801             :                        instrumentation);
     802         180 :         pei->instrumentation = instrumentation;
     803             : 
     804         180 :         if (estate->es_jit_flags != PGJIT_NONE)
     805             :         {
     806          24 :             jit_instrumentation = shm_toc_allocate(pcxt->toc,
     807             :                                                    jit_instrumentation_len);
     808          24 :             jit_instrumentation->num_workers = nworkers;
     809          24 :             memset(jit_instrumentation->jit_instr, 0,
     810             :                    sizeof(JitInstrumentation) * nworkers);
     811          24 :             shm_toc_insert(pcxt->toc, PARALLEL_KEY_JIT_INSTRUMENTATION,
     812             :                            jit_instrumentation);
     813          24 :             pei->jit_instrumentation = jit_instrumentation;
     814             :         }
     815             :     }
     816             : 
     817             :     /*
     818             :      * Create a DSA area that can be used by the leader and all workers.
     819             :      * (However, if we failed to create a DSM and are using private memory
     820             :      * instead, then skip this.)
     821             :      */
     822         652 :     if (pcxt->seg != NULL)
     823             :     {
     824             :         char       *area_space;
     825             : 
     826         652 :         area_space = shm_toc_allocate(pcxt->toc, dsa_minsize);
     827         652 :         shm_toc_insert(pcxt->toc, PARALLEL_KEY_DSA, area_space);
     828         652 :         pei->area = dsa_create_in_place(area_space, dsa_minsize,
     829             :                                         LWTRANCHE_PARALLEL_QUERY_DSA,
     830             :                                         pcxt->seg);
     831             : 
     832             :         /*
     833             :          * Serialize parameters, if any, using DSA storage.  We don't dare use
     834             :          * the main parallel query DSM for this because we might relaunch
     835             :          * workers after the values have changed (and thus the amount of
     836             :          * storage required has changed).
     837             :          */
     838         652 :         if (!bms_is_empty(sendParams))
     839             :         {
     840          18 :             pei->param_exec = SerializeParamExecParams(estate, sendParams,
     841             :                                                        pei->area);
     842          18 :             fpes->param_exec = pei->param_exec;
     843             :         }
     844             :     }
     845             : 
     846             :     /*
     847             :      * Give parallel-aware nodes a chance to initialize their shared data.
     848             :      * This also initializes the elements of instrumentation->ps_instrument,
     849             :      * if it exists.
     850             :      */
     851         652 :     d.pcxt = pcxt;
     852         652 :     d.instrumentation = instrumentation;
     853         652 :     d.nnodes = 0;
     854             : 
     855             :     /* Install our DSA area while initializing the plan. */
     856         652 :     estate->es_query_dsa = pei->area;
     857         652 :     ExecParallelInitializeDSM(planstate, &d);
     858         652 :     estate->es_query_dsa = NULL;
     859             : 
     860             :     /*
     861             :      * Make sure that the world hasn't shifted under our feet.  This could
     862             :      * probably just be an Assert(), but let's be conservative for now.
     863             :      */
     864         652 :     if (e.nnodes != d.nnodes)
     865           0 :         elog(ERROR, "inconsistent count of PlanState nodes");
     866             : 
     867             :     /* OK, we're ready to rock and roll. */
     868         652 :     return pei;
     869             : }
     870             : 
     871             : /*
     872             :  * Set up tuple queue readers to read the results of a parallel subplan.
     873             :  *
     874             :  * This is separate from ExecInitParallelPlan() because we can launch the
     875             :  * worker processes and let them start doing something before we do this.
     876             :  */
     877             : void
     878         892 : ExecParallelCreateReaders(ParallelExecutorInfo *pei)
     879             : {
     880         892 :     int         nworkers = pei->pcxt->nworkers_launched;
     881             :     int         i;
     882             : 
     883             :     Assert(pei->reader == NULL);
     884             : 
     885         892 :     if (nworkers > 0)
     886             :     {
     887         892 :         pei->reader = (TupleQueueReader **)
     888         892 :             palloc(nworkers * sizeof(TupleQueueReader *));
     889             : 
     890        3324 :         for (i = 0; i < nworkers; i++)
     891             :         {
     892        2432 :             shm_mq_set_handle(pei->tqueue[i],
     893        2432 :                               pei->pcxt->worker[i].bgwhandle);
     894        2432 :             pei->reader[i] = CreateTupleQueueReader(pei->tqueue[i]);
     895             :         }
     896             :     }
     897         892 : }
     898             : 
     899             : /*
     900             :  * Re-initialize the parallel executor shared memory state before launching
     901             :  * a fresh batch of workers.
     902             :  */
     903             : void
     904         258 : ExecParallelReinitialize(PlanState *planstate,
     905             :                          ParallelExecutorInfo *pei,
     906             :                          Bitmapset *sendParams)
     907             : {
     908         258 :     EState     *estate = planstate->state;
     909             :     FixedParallelExecutorState *fpes;
     910             : 
     911             :     /* Old workers must already be shut down */
     912             :     Assert(pei->finished);
     913             : 
     914             :     /*
     915             :      * Force any initplan outputs that we're going to pass to workers to be
     916             :      * evaluated, if they weren't already (see comments in
     917             :      * ExecInitParallelPlan).
     918             :      */
     919         258 :     ExecSetParamPlanMulti(sendParams, GetPerTupleExprContext(estate));
     920             : 
     921         258 :     ReinitializeParallelDSM(pei->pcxt);
     922         258 :     pei->tqueue = ExecParallelSetupTupleQueues(pei->pcxt, true);
     923         258 :     pei->reader = NULL;
     924         258 :     pei->finished = false;
     925             : 
     926         258 :     fpes = shm_toc_lookup(pei->pcxt->toc, PARALLEL_KEY_EXECUTOR_FIXED, false);
     927             : 
     928             :     /* Free any serialized parameters from the last round. */
     929         258 :     if (DsaPointerIsValid(fpes->param_exec))
     930             :     {
     931           0 :         dsa_free(pei->area, fpes->param_exec);
     932           0 :         fpes->param_exec = InvalidDsaPointer;
     933             :     }
     934             : 
     935             :     /* Serialize current parameter values if required. */
     936         258 :     if (!bms_is_empty(sendParams))
     937             :     {
     938           0 :         pei->param_exec = SerializeParamExecParams(estate, sendParams,
     939             :                                                    pei->area);
     940           0 :         fpes->param_exec = pei->param_exec;
     941             :     }
     942             : 
     943             :     /* Traverse plan tree and let each child node reset associated state. */
     944         258 :     estate->es_query_dsa = pei->area;
     945         258 :     ExecParallelReInitializeDSM(planstate, pei->pcxt);
     946         258 :     estate->es_query_dsa = NULL;
     947         258 : }
     948             : 
     949             : /*
     950             :  * Traverse plan tree to reinitialize per-node dynamic shared memory state
     951             :  */
     952             : static bool
     953         666 : ExecParallelReInitializeDSM(PlanState *planstate,
     954             :                             ParallelContext *pcxt)
     955             : {
     956         666 :     if (planstate == NULL)
     957           0 :         return false;
     958             : 
     959             :     /*
     960             :      * Call reinitializers for DSM-using plan nodes.
     961             :      */
     962         666 :     switch (nodeTag(planstate))
     963             :     {
     964         276 :         case T_SeqScanState:
     965         276 :             if (planstate->plan->parallel_aware)
     966         228 :                 ExecSeqScanReInitializeDSM((SeqScanState *) planstate,
     967             :                                            pcxt);
     968         276 :             break;
     969          12 :         case T_IndexScanState:
     970          12 :             if (planstate->plan->parallel_aware)
     971          12 :                 ExecIndexScanReInitializeDSM((IndexScanState *) planstate,
     972             :                                              pcxt);
     973          12 :             break;
     974          12 :         case T_IndexOnlyScanState:
     975          12 :             if (planstate->plan->parallel_aware)
     976          12 :                 ExecIndexOnlyScanReInitializeDSM((IndexOnlyScanState *) planstate,
     977             :                                                  pcxt);
     978          12 :             break;
     979           0 :         case T_ForeignScanState:
     980           0 :             if (planstate->plan->parallel_aware)
     981           0 :                 ExecForeignScanReInitializeDSM((ForeignScanState *) planstate,
     982             :                                                pcxt);
     983           0 :             break;
     984           0 :         case T_AppendState:
     985           0 :             if (planstate->plan->parallel_aware)
     986           0 :                 ExecAppendReInitializeDSM((AppendState *) planstate, pcxt);
     987           0 :             break;
     988           0 :         case T_CustomScanState:
     989           0 :             if (planstate->plan->parallel_aware)
     990           0 :                 ExecCustomScanReInitializeDSM((CustomScanState *) planstate,
     991             :                                               pcxt);
     992           0 :             break;
     993          54 :         case T_BitmapHeapScanState:
     994          54 :             if (planstate->plan->parallel_aware)
     995          54 :                 ExecBitmapHeapReInitializeDSM((BitmapHeapScanState *) planstate,
     996             :                                               pcxt);
     997          54 :             break;
     998          96 :         case T_HashJoinState:
     999          96 :             if (planstate->plan->parallel_aware)
    1000          48 :                 ExecHashJoinReInitializeDSM((HashJoinState *) planstate,
    1001             :                                             pcxt);
    1002          96 :             break;
    1003         126 :         case T_HashState:
    1004             :         case T_SortState:
    1005             :         case T_IncrementalSortState:
    1006             :         case T_MemoizeState:
    1007             :             /* these nodes have DSM state, but no reinitialization is required */
    1008         126 :             break;
    1009             : 
    1010          90 :         default:
    1011          90 :             break;
    1012             :     }
    1013             : 
    1014         666 :     return planstate_tree_walker(planstate, ExecParallelReInitializeDSM, pcxt);
    1015             : }
    1016             : 
    1017             : /*
    1018             :  * Copy instrumentation information about this node and its descendants from
    1019             :  * dynamic shared memory.
    1020             :  */
    1021             : static bool
    1022        1032 : ExecParallelRetrieveInstrumentation(PlanState *planstate,
    1023             :                                     SharedExecutorInstrumentation *instrumentation)
    1024             : {
    1025             :     Instrumentation *instrument;
    1026             :     int         i;
    1027             :     int         n;
    1028             :     int         ibytes;
    1029        1032 :     int         plan_node_id = planstate->plan->plan_node_id;
    1030             :     MemoryContext oldcontext;
    1031             : 
    1032             :     /* Find the instrumentation for this node. */
    1033        4668 :     for (i = 0; i < instrumentation->num_plan_nodes; ++i)
    1034        4668 :         if (instrumentation->plan_node_id[i] == plan_node_id)
    1035        1032 :             break;
    1036        1032 :     if (i >= instrumentation->num_plan_nodes)
    1037           0 :         elog(ERROR, "plan node %d not found", plan_node_id);
    1038             : 
    1039             :     /* Accumulate the statistics from all workers. */
    1040        1032 :     instrument = GetInstrumentationArray(instrumentation);
    1041        1032 :     instrument += i * instrumentation->num_workers;
    1042        2718 :     for (n = 0; n < instrumentation->num_workers; ++n)
    1043        1686 :         InstrAggNode(planstate->instrument, &instrument[n]);
    1044             : 
    1045             :     /*
    1046             :      * Also store the per-worker detail.
    1047             :      *
    1048             :      * Worker instrumentation should be allocated in the same context as the
    1049             :      * regular instrumentation information, which is the per-query context.
    1050             :      * Switch into per-query memory context.
    1051             :      */
    1052        1032 :     oldcontext = MemoryContextSwitchTo(planstate->state->es_query_cxt);
    1053        1032 :     ibytes = mul_size(instrumentation->num_workers, sizeof(Instrumentation));
    1054        1032 :     planstate->worker_instrument =
    1055        1032 :         palloc(ibytes + offsetof(WorkerInstrumentation, instrument));
    1056        1032 :     MemoryContextSwitchTo(oldcontext);
    1057             : 
    1058        1032 :     planstate->worker_instrument->num_workers = instrumentation->num_workers;
    1059        1032 :     memcpy(&planstate->worker_instrument->instrument, instrument, ibytes);
    1060             : 
    1061             :     /* Perform any node-type-specific work that needs to be done. */
    1062        1032 :     switch (nodeTag(planstate))
    1063             :     {
    1064          12 :         case T_SortState:
    1065          12 :             ExecSortRetrieveInstrumentation((SortState *) planstate);
    1066          12 :             break;
    1067           0 :         case T_IncrementalSortState:
    1068           0 :             ExecIncrementalSortRetrieveInstrumentation((IncrementalSortState *) planstate);
    1069           0 :             break;
    1070          84 :         case T_HashState:
    1071          84 :             ExecHashRetrieveInstrumentation((HashState *) planstate);
    1072          84 :             break;
    1073         108 :         case T_AggState:
    1074         108 :             ExecAggRetrieveInstrumentation((AggState *) planstate);
    1075         108 :             break;
    1076           0 :         case T_MemoizeState:
    1077           0 :             ExecMemoizeRetrieveInstrumentation((MemoizeState *) planstate);
    1078           0 :             break;
    1079         828 :         default:
    1080         828 :             break;
    1081             :     }
    1082             : 
    1083        1032 :     return planstate_tree_walker(planstate, ExecParallelRetrieveInstrumentation,
    1084             :                                  instrumentation);
    1085             : }
    1086             : 
    1087             : /*
    1088             :  * Add up the workers' JIT instrumentation from dynamic shared memory.
    1089             :  */
    1090             : static void
    1091          24 : ExecParallelRetrieveJitInstrumentation(PlanState *planstate,
    1092             :                                        SharedJitInstrumentation *shared_jit)
    1093             : {
    1094             :     JitInstrumentation *combined;
    1095             :     int         ibytes;
    1096             : 
    1097             :     int         n;
    1098             : 
    1099             :     /*
    1100             :      * Accumulate worker JIT instrumentation into the combined JIT
    1101             :      * instrumentation, allocating it if required.
    1102             :      */
    1103          24 :     if (!planstate->state->es_jit_worker_instr)
    1104          24 :         planstate->state->es_jit_worker_instr =
    1105          24 :             MemoryContextAllocZero(planstate->state->es_query_cxt, sizeof(JitInstrumentation));
    1106          24 :     combined = planstate->state->es_jit_worker_instr;
    1107             : 
    1108             :     /* Accumulate all the workers' instrumentations. */
    1109          72 :     for (n = 0; n < shared_jit->num_workers; ++n)
    1110          48 :         InstrJitAgg(combined, &shared_jit->jit_instr[n]);
    1111             : 
    1112             :     /*
    1113             :      * Store the per-worker detail.
    1114             :      *
    1115             :      * Similar to ExecParallelRetrieveInstrumentation(), allocate the
    1116             :      * instrumentation in per-query context.
    1117             :      */
    1118          24 :     ibytes = offsetof(SharedJitInstrumentation, jit_instr)
    1119          24 :         + mul_size(shared_jit->num_workers, sizeof(JitInstrumentation));
    1120          24 :     planstate->worker_jit_instrument =
    1121          24 :         MemoryContextAlloc(planstate->state->es_query_cxt, ibytes);
    1122             : 
    1123          24 :     memcpy(planstate->worker_jit_instrument, shared_jit, ibytes);
    1124          24 : }
    1125             : 
    1126             : /*
    1127             :  * Finish parallel execution.  We wait for parallel workers to finish, and
    1128             :  * accumulate their buffer/WAL usage.
    1129             :  */
    1130             : void
    1131        1644 : ExecParallelFinish(ParallelExecutorInfo *pei)
    1132             : {
    1133        1644 :     int         nworkers = pei->pcxt->nworkers_launched;
    1134             :     int         i;
    1135             : 
    1136             :     /* Make this be a no-op if called twice in a row. */
    1137        1644 :     if (pei->finished)
    1138         740 :         return;
    1139             : 
    1140             :     /*
    1141             :      * Detach from tuple queues ASAP, so that any still-active workers will
    1142             :      * notice that no further results are wanted.
    1143             :      */
    1144         904 :     if (pei->tqueue != NULL)
    1145             :     {
    1146        3330 :         for (i = 0; i < nworkers; i++)
    1147        2426 :             shm_mq_detach(pei->tqueue[i]);
    1148         904 :         pfree(pei->tqueue);
    1149         904 :         pei->tqueue = NULL;
    1150             :     }
    1151             : 
    1152             :     /*
    1153             :      * While we're waiting for the workers to finish, let's get rid of the
    1154             :      * tuple queue readers.  (Any other local cleanup could be done here too.)
    1155             :      */
    1156         904 :     if (pei->reader != NULL)
    1157             :     {
    1158        3312 :         for (i = 0; i < nworkers; i++)
    1159        2426 :             DestroyTupleQueueReader(pei->reader[i]);
    1160         886 :         pfree(pei->reader);
    1161         886 :         pei->reader = NULL;
    1162             :     }
    1163             : 
    1164             :     /* Now wait for the workers to finish. */
    1165         904 :     WaitForParallelWorkersToFinish(pei->pcxt);
    1166             : 
    1167             :     /*
    1168             :      * Next, accumulate buffer/WAL usage.  (This must wait for the workers to
    1169             :      * finish, or we might get incomplete data.)
    1170             :      */
    1171        3330 :     for (i = 0; i < nworkers; i++)
    1172        2426 :         InstrAccumParallelQuery(&pei->buffer_usage[i], &pei->wal_usage[i]);
    1173             : 
    1174         904 :     pei->finished = true;
    1175             : }
    1176             : 
    1177             : /*
    1178             :  * Accumulate instrumentation, and then clean up whatever ParallelExecutorInfo
    1179             :  * resources still exist after ExecParallelFinish.  We separate these
    1180             :  * routines because someone might want to examine the contents of the DSM
    1181             :  * after ExecParallelFinish and before calling this routine.
    1182             :  */
    1183             : void
    1184         646 : ExecParallelCleanup(ParallelExecutorInfo *pei)
    1185             : {
    1186             :     /* Accumulate instrumentation, if any. */
    1187         646 :     if (pei->instrumentation)
    1188         180 :         ExecParallelRetrieveInstrumentation(pei->planstate,
    1189             :                                             pei->instrumentation);
    1190             : 
    1191             :     /* Accumulate JIT instrumentation, if any. */
    1192         646 :     if (pei->jit_instrumentation)
    1193          24 :         ExecParallelRetrieveJitInstrumentation(pei->planstate,
    1194          24 :                                                pei->jit_instrumentation);
    1195             : 
    1196             :     /* Free any serialized parameters. */
    1197         646 :     if (DsaPointerIsValid(pei->param_exec))
    1198             :     {
    1199          18 :         dsa_free(pei->area, pei->param_exec);
    1200          18 :         pei->param_exec = InvalidDsaPointer;
    1201             :     }
    1202         646 :     if (pei->area != NULL)
    1203             :     {
    1204         646 :         dsa_detach(pei->area);
    1205         646 :         pei->area = NULL;
    1206             :     }
    1207         646 :     if (pei->pcxt != NULL)
    1208             :     {
    1209         646 :         DestroyParallelContext(pei->pcxt);
    1210         646 :         pei->pcxt = NULL;
    1211             :     }
    1212         646 :     pfree(pei);
    1213         646 : }
    1214             : 
    1215             : /*
    1216             :  * Create a DestReceiver to write tuples we produce to the shm_mq designated
    1217             :  * for that purpose.
    1218             :  */
    1219             : static DestReceiver *
    1220        2432 : ExecParallelGetReceiver(dsm_segment *seg, shm_toc *toc)
    1221             : {
    1222             :     char       *mqspace;
    1223             :     shm_mq     *mq;
    1224             : 
    1225        2432 :     mqspace = shm_toc_lookup(toc, PARALLEL_KEY_TUPLE_QUEUE, false);
    1226        2432 :     mqspace += ParallelWorkerNumber * PARALLEL_TUPLE_QUEUE_SIZE;
    1227        2432 :     mq = (shm_mq *) mqspace;
    1228        2432 :     shm_mq_set_sender(mq, MyProc);
    1229        2432 :     return CreateTupleQueueDestReceiver(shm_mq_attach(mq, seg, NULL));
    1230             : }
    1231             : 
    1232             : /*
    1233             :  * Create a QueryDesc for the PlannedStmt we are to execute, and return it.
    1234             :  */
    1235             : static QueryDesc *
    1236        2432 : ExecParallelGetQueryDesc(shm_toc *toc, DestReceiver *receiver,
    1237             :                          int instrument_options)
    1238             : {
    1239             :     char       *pstmtspace;
    1240             :     char       *paramspace;
    1241             :     PlannedStmt *pstmt;
    1242             :     ParamListInfo paramLI;
    1243             :     char       *queryString;
    1244             : 
    1245             :     /* Get the query string from shared memory */
    1246        2432 :     queryString = shm_toc_lookup(toc, PARALLEL_KEY_QUERY_TEXT, false);
    1247             : 
    1248             :     /* Reconstruct leader-supplied PlannedStmt. */
    1249        2432 :     pstmtspace = shm_toc_lookup(toc, PARALLEL_KEY_PLANNEDSTMT, false);
    1250        2432 :     pstmt = (PlannedStmt *) stringToNode(pstmtspace);
    1251             : 
    1252             :     /* Reconstruct ParamListInfo. */
    1253        2432 :     paramspace = shm_toc_lookup(toc, PARALLEL_KEY_PARAMLISTINFO, false);
    1254        2432 :     paramLI = RestoreParamList(&paramspace);
    1255             : 
    1256             :     /* Create a QueryDesc for the query. */
    1257        2432 :     return CreateQueryDesc(pstmt,
    1258             :                            queryString,
    1259             :                            GetActiveSnapshot(), InvalidSnapshot,
    1260             :                            receiver, paramLI, NULL, instrument_options);
    1261             : }
    1262             : 
    1263             : /*
    1264             :  * Copy instrumentation information from this node and its descendants into
    1265             :  * dynamic shared memory, so that the parallel leader can retrieve it.
    1266             :  */
    1267             : static bool
    1268        2382 : ExecParallelReportInstrumentation(PlanState *planstate,
    1269             :                                   SharedExecutorInstrumentation *instrumentation)
    1270             : {
    1271             :     int         i;
    1272        2382 :     int         plan_node_id = planstate->plan->plan_node_id;
    1273             :     Instrumentation *instrument;
    1274             : 
    1275        2382 :     InstrEndLoop(planstate->instrument);
    1276             : 
    1277             :     /*
    1278             :      * If we shuffled the plan_node_id values in ps_instrument into sorted
    1279             :      * order, we could use binary search here.  This might matter someday if
    1280             :      * we're pushing down sufficiently large plan trees.  For now, do it the
    1281             :      * slow, dumb way.
    1282             :      */
    1283        7842 :     for (i = 0; i < instrumentation->num_plan_nodes; ++i)
    1284        7842 :         if (instrumentation->plan_node_id[i] == plan_node_id)
    1285        2382 :             break;
    1286        2382 :     if (i >= instrumentation->num_plan_nodes)
    1287           0 :         elog(ERROR, "plan node %d not found", plan_node_id);
    1288             : 
    1289             :     /*
    1290             :      * Add our statistics to the per-node, per-worker totals.  It's possible
    1291             :      * that this could happen more than once if we relaunched workers.
    1292             :      */
    1293        2382 :     instrument = GetInstrumentationArray(instrumentation);
    1294        2382 :     instrument += i * instrumentation->num_workers;
    1295             :     Assert(IsParallelWorker());
    1296             :     Assert(ParallelWorkerNumber < instrumentation->num_workers);
    1297        2382 :     InstrAggNode(&instrument[ParallelWorkerNumber], planstate->instrument);
    1298             : 
    1299        2382 :     return planstate_tree_walker(planstate, ExecParallelReportInstrumentation,
    1300             :                                  instrumentation);
    1301             : }
    1302             : 
    1303             : /*
    1304             :  * Initialize the PlanState and its descendants with the information
    1305             :  * retrieved from shared memory.  This has to be done once the PlanState
    1306             :  * is allocated and initialized by executor; that is, after ExecutorStart().
    1307             :  */
    1308             : static bool
    1309        8102 : ExecParallelInitializeWorker(PlanState *planstate, ParallelWorkerContext *pwcxt)
    1310             : {
    1311        8102 :     if (planstate == NULL)
    1312           0 :         return false;
    1313             : 
    1314        8102 :     switch (nodeTag(planstate))
    1315             :     {
    1316        3290 :         case T_SeqScanState:
    1317        3290 :             if (planstate->plan->parallel_aware)
    1318        2662 :                 ExecSeqScanInitializeWorker((SeqScanState *) planstate, pwcxt);
    1319        3290 :             break;
    1320         398 :         case T_IndexScanState:
    1321         398 :             if (planstate->plan->parallel_aware)
    1322          96 :                 ExecIndexScanInitializeWorker((IndexScanState *) planstate,
    1323             :                                               pwcxt);
    1324         398 :             break;
    1325         236 :         case T_IndexOnlyScanState:
    1326         236 :             if (planstate->plan->parallel_aware)
    1327         200 :                 ExecIndexOnlyScanInitializeWorker((IndexOnlyScanState *) planstate,
    1328             :                                                   pwcxt);
    1329         236 :             break;
    1330           0 :         case T_ForeignScanState:
    1331           0 :             if (planstate->plan->parallel_aware)
    1332           0 :                 ExecForeignScanInitializeWorker((ForeignScanState *) planstate,
    1333             :                                                 pwcxt);
    1334           0 :             break;
    1335         378 :         case T_AppendState:
    1336         378 :             if (planstate->plan->parallel_aware)
    1337         318 :                 ExecAppendInitializeWorker((AppendState *) planstate, pwcxt);
    1338         378 :             break;
    1339           0 :         case T_CustomScanState:
    1340           0 :             if (planstate->plan->parallel_aware)
    1341           0 :                 ExecCustomScanInitializeWorker((CustomScanState *) planstate,
    1342             :                                                pwcxt);
    1343           0 :             break;
    1344         280 :         case T_BitmapHeapScanState:
    1345         280 :             if (planstate->plan->parallel_aware)
    1346         278 :                 ExecBitmapHeapInitializeWorker((BitmapHeapScanState *) planstate,
    1347             :                                                pwcxt);
    1348         280 :             break;
    1349         546 :         case T_HashJoinState:
    1350         546 :             if (planstate->plan->parallel_aware)
    1351         306 :                 ExecHashJoinInitializeWorker((HashJoinState *) planstate,
    1352             :                                              pwcxt);
    1353         546 :             break;
    1354         546 :         case T_HashState:
    1355             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
    1356         546 :             ExecHashInitializeWorker((HashState *) planstate, pwcxt);
    1357         546 :             break;
    1358         454 :         case T_SortState:
    1359             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
    1360         454 :             ExecSortInitializeWorker((SortState *) planstate, pwcxt);
    1361         454 :             break;
    1362           0 :         case T_IncrementalSortState:
    1363             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
    1364           0 :             ExecIncrementalSortInitializeWorker((IncrementalSortState *) planstate,
    1365             :                                                 pwcxt);
    1366           0 :             break;
    1367        1532 :         case T_AggState:
    1368             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
    1369        1532 :             ExecAggInitializeWorker((AggState *) planstate, pwcxt);
    1370        1532 :             break;
    1371          12 :         case T_MemoizeState:
    1372             :             /* even when not parallel-aware, for EXPLAIN ANALYZE */
    1373          12 :             ExecMemoizeInitializeWorker((MemoizeState *) planstate, pwcxt);
    1374          12 :             break;
    1375         430 :         default:
    1376         430 :             break;
    1377             :     }
    1378             : 
    1379        8102 :     return planstate_tree_walker(planstate, ExecParallelInitializeWorker,
    1380             :                                  pwcxt);
    1381             : }
    1382             : 
    1383             : /*
    1384             :  * Main entrypoint for parallel query worker processes.
    1385             :  *
    1386             :  * We reach this function from ParallelWorkerMain, so the setup necessary to
    1387             :  * create a sensible parallel environment has already been done;
    1388             :  * ParallelWorkerMain worries about stuff like the transaction state, combo
    1389             :  * CID mappings, and GUC values, so we don't need to deal with any of that
    1390             :  * here.
    1391             :  *
    1392             :  * Our job is to deal with concerns specific to the executor.  The parallel
    1393             :  * group leader will have stored a serialized PlannedStmt, and it's our job
    1394             :  * to execute that plan and write the resulting tuples to the appropriate
    1395             :  * tuple queue.  Various bits of supporting information that we need in order
    1396             :  * to do this are also stored in the dsm_segment and can be accessed through
    1397             :  * the shm_toc.
    1398             :  */
    1399             : void
    1400        2432 : ParallelQueryMain(dsm_segment *seg, shm_toc *toc)
    1401             : {
    1402             :     FixedParallelExecutorState *fpes;
    1403             :     BufferUsage *buffer_usage;
    1404             :     WalUsage   *wal_usage;
    1405             :     DestReceiver *receiver;
    1406             :     QueryDesc  *queryDesc;
    1407             :     SharedExecutorInstrumentation *instrumentation;
    1408             :     SharedJitInstrumentation *jit_instrumentation;
    1409        2432 :     int         instrument_options = 0;
    1410             :     void       *area_space;
    1411             :     dsa_area   *area;
    1412             :     ParallelWorkerContext pwcxt;
    1413             : 
    1414             :     /* Get fixed-size state. */
    1415        2432 :     fpes = shm_toc_lookup(toc, PARALLEL_KEY_EXECUTOR_FIXED, false);
    1416             : 
    1417             :     /* Set up DestReceiver, SharedExecutorInstrumentation, and QueryDesc. */
    1418        2432 :     receiver = ExecParallelGetReceiver(seg, toc);
    1419        2432 :     instrumentation = shm_toc_lookup(toc, PARALLEL_KEY_INSTRUMENTATION, true);
    1420        2432 :     if (instrumentation != NULL)
    1421         726 :         instrument_options = instrumentation->instrument_options;
    1422        2432 :     jit_instrumentation = shm_toc_lookup(toc, PARALLEL_KEY_JIT_INSTRUMENTATION,
    1423             :                                          true);
    1424        2432 :     queryDesc = ExecParallelGetQueryDesc(toc, receiver, instrument_options);
    1425             : 
    1426             :     /* Setting debug_query_string for individual workers */
    1427        2432 :     debug_query_string = queryDesc->sourceText;
    1428             : 
    1429             :     /* Report workers' query for monitoring purposes */
    1430        2432 :     pgstat_report_activity(STATE_RUNNING, debug_query_string);
    1431             : 
    1432             :     /* Attach to the dynamic shared memory area. */
    1433        2432 :     area_space = shm_toc_lookup(toc, PARALLEL_KEY_DSA, false);
    1434        2432 :     area = dsa_attach_in_place(area_space, seg);
    1435             : 
    1436             :     /* Start up the executor */
    1437        2432 :     queryDesc->plannedstmt->jitFlags = fpes->jit_flags;
    1438        2432 :     ExecutorStart(queryDesc, fpes->eflags);
    1439             : 
    1440             :     /* Special executor initialization steps for parallel workers */
    1441        2432 :     queryDesc->planstate->state->es_query_dsa = area;
    1442        2432 :     if (DsaPointerIsValid(fpes->param_exec))
    1443             :     {
    1444             :         char       *paramexec_space;
    1445             : 
    1446          48 :         paramexec_space = dsa_get_address(area, fpes->param_exec);
    1447          48 :         RestoreParamExecParams(paramexec_space, queryDesc->estate);
    1448             :     }
    1449        2432 :     pwcxt.toc = toc;
    1450        2432 :     pwcxt.seg = seg;
    1451        2432 :     ExecParallelInitializeWorker(queryDesc->planstate, &pwcxt);
    1452             : 
    1453             :     /* Pass down any tuple bound */
    1454        2432 :     ExecSetTupleBound(fpes->tuples_needed, queryDesc->planstate);
    1455             : 
    1456             :     /*
    1457             :      * Prepare to track buffer/WAL usage during query execution.
    1458             :      *
    1459             :      * We do this after starting up the executor to match what happens in the
    1460             :      * leader, which also doesn't count buffer accesses and WAL activity that
    1461             :      * occur during executor startup.
    1462             :      */
    1463        2432 :     InstrStartParallelQuery();
    1464             : 
    1465             :     /*
    1466             :      * Run the plan.  If we specified a tuple bound, be careful not to demand
    1467             :      * more tuples than that.
    1468             :      */
    1469        2432 :     ExecutorRun(queryDesc,
    1470             :                 ForwardScanDirection,
    1471        2432 :                 fpes->tuples_needed < 0 ? (int64) 0 : fpes->tuples_needed,
    1472             :                 true);
    1473             : 
    1474             :     /* Shut down the executor */
    1475        2426 :     ExecutorFinish(queryDesc);
    1476             : 
    1477             :     /* Report buffer/WAL usage during parallel execution. */
    1478        2426 :     buffer_usage = shm_toc_lookup(toc, PARALLEL_KEY_BUFFER_USAGE, false);
    1479        2426 :     wal_usage = shm_toc_lookup(toc, PARALLEL_KEY_WAL_USAGE, false);
    1480        2426 :     InstrEndParallelQuery(&buffer_usage[ParallelWorkerNumber],
    1481        2426 :                           &wal_usage[ParallelWorkerNumber]);
    1482             : 
    1483             :     /* Report instrumentation data if any instrumentation options are set. */
    1484        2426 :     if (instrumentation != NULL)
    1485         726 :         ExecParallelReportInstrumentation(queryDesc->planstate,
    1486             :                                           instrumentation);
    1487             : 
    1488             :     /* Report JIT instrumentation data if any */
    1489        2426 :     if (queryDesc->estate->es_jit && jit_instrumentation != NULL)
    1490             :     {
    1491             :         Assert(ParallelWorkerNumber < jit_instrumentation->num_workers);
    1492         144 :         jit_instrumentation->jit_instr[ParallelWorkerNumber] =
    1493         144 :             queryDesc->estate->es_jit->instr;
    1494             :     }
    1495             : 
    1496             :     /* Must do this after capturing instrumentation. */
    1497        2426 :     ExecutorEnd(queryDesc);
    1498             : 
    1499             :     /* Cleanup. */
    1500        2426 :     dsa_detach(area);
    1501        2426 :     FreeQueryDesc(queryDesc);
    1502        2426 :     receiver->rDestroy(receiver);
    1503        2426 : }

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