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https://github.com/postgres/postgres.git
synced 2025-06-23 14:01:44 +03:00
Avoid holding a directory FD open across assorted SRF calls.
This extends the fixes made in commit 085b6b667 to other SRFs with the
same bug, namely pg_logdir_ls(), pgrowlocks(), pg_timezone_names(),
pg_ls_dir(), and pg_tablespace_databases().
Also adjust various comments and documentation to warn against
expecting to clean up resources during a ValuePerCall SRF's final
call.
Back-patch to all supported branches, since these functions were
all born broken.
Justin Pryzby, with cosmetic tweaks by me
Discussion: https://postgr.es/m/20200308173103.GC1357@telsasoft.com
This commit is contained in:
Tom Lane
@ -54,13 +54,6 @@ PG_FUNCTION_INFO_V1(pgrowlocks);
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#define NCHARS 32
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typedef struct
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{
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Relation rel;
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TableScanDesc scan;
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int ncolumns;
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} MyData;
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#define Atnum_tid 0
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#define Atnum_xmax 1
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#define Atnum_ismulti 2
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@ -71,84 +64,86 @@ typedef struct
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Datum
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pgrowlocks(PG_FUNCTION_ARGS)
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{
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FuncCallContext *funcctx;
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text *relname = PG_GETARG_TEXT_PP(0);
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ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
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bool randomAccess;
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TupleDesc tupdesc;
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Tuplestorestate *tupstore;
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AttInMetadata *attinmeta;
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Relation rel;
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RangeVar *relrv;
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TableScanDesc scan;
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HeapScanDesc hscan;
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HeapTuple tuple;
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TupleDesc tupdesc;
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AttInMetadata *attinmeta;
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Datum result;
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MyData *mydata;
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Relation rel;
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MemoryContext oldcontext;
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AclResult aclresult;
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char **values;
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if (SRF_IS_FIRSTCALL())
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{
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text *relname;
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RangeVar *relrv;
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MemoryContext oldcontext;
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AclResult aclresult;
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/* check to see if caller supports us returning a tuplestore */
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if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("set-valued function called in context that cannot accept a set")));
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if (!(rsinfo->allowedModes & SFRM_Materialize))
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ereport(ERROR,
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(errcode(ERRCODE_SYNTAX_ERROR),
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errmsg("materialize mode required, but it is not allowed in this context")));
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funcctx = SRF_FIRSTCALL_INIT();
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oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
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/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
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oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
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/* Build a tuple descriptor for our result type */
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if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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attinmeta = TupleDescGetAttInMetadata(tupdesc);
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funcctx->attinmeta = attinmeta;
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randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
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tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
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rsinfo->returnMode = SFRM_Materialize;
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rsinfo->setResult = tupstore;
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rsinfo->setDesc = tupdesc;
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relname = PG_GETARG_TEXT_PP(0);
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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MemoryContextSwitchTo(oldcontext);
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if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
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ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("only heap AM is supported")));
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/* Access the table */
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
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ereport(ERROR,
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(errcode(ERRCODE_WRONG_OBJECT_TYPE),
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errmsg("\"%s\" is a partitioned table",
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RelationGetRelationName(rel)),
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errdetail("Partitioned tables do not contain rows.")));
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else if (rel->rd_rel->relkind != RELKIND_RELATION)
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ereport(ERROR,
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(errcode(ERRCODE_WRONG_OBJECT_TYPE),
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errmsg("\"%s\" is not a table",
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RelationGetRelationName(rel))));
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if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
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ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("only heap AM is supported")));
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/*
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* check permissions: must have SELECT on table or be in
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* pg_stat_scan_tables
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*/
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aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
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ACL_SELECT);
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if (aclresult != ACLCHECK_OK)
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aclresult = is_member_of_role(GetUserId(), DEFAULT_ROLE_STAT_SCAN_TABLES) ? ACLCHECK_OK : ACLCHECK_NO_PRIV;
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if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
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ereport(ERROR,
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(errcode(ERRCODE_WRONG_OBJECT_TYPE),
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errmsg("\"%s\" is a partitioned table",
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RelationGetRelationName(rel)),
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errdetail("Partitioned tables do not contain rows.")));
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else if (rel->rd_rel->relkind != RELKIND_RELATION)
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ereport(ERROR,
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(errcode(ERRCODE_WRONG_OBJECT_TYPE),
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errmsg("\"%s\" is not a table",
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RelationGetRelationName(rel))));
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if (aclresult != ACLCHECK_OK)
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aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
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RelationGetRelationName(rel));
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/*
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* check permissions: must have SELECT on table or be in
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* pg_stat_scan_tables
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*/
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aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
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ACL_SELECT);
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if (aclresult != ACLCHECK_OK)
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aclresult = is_member_of_role(GetUserId(), DEFAULT_ROLE_STAT_SCAN_TABLES) ? ACLCHECK_OK : ACLCHECK_NO_PRIV;
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scan = table_beginscan(rel, GetActiveSnapshot(), 0, NULL);
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hscan = (HeapScanDesc) scan;
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mydata = palloc(sizeof(*mydata));
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mydata->rel = rel;
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mydata->scan = scan;
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mydata->ncolumns = tupdesc->natts;
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funcctx->user_fctx = mydata;
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if (aclresult != ACLCHECK_OK)
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aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
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RelationGetRelationName(rel));
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MemoryContextSwitchTo(oldcontext);
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}
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funcctx = SRF_PERCALL_SETUP();
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attinmeta = funcctx->attinmeta;
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mydata = (MyData *) funcctx->user_fctx;
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scan = mydata->scan;
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/* Scan the relation */
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scan = table_beginscan(rel, GetActiveSnapshot(), 0, NULL);
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hscan = (HeapScanDesc) scan;
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/* scan the relation */
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attinmeta = TupleDescGetAttInMetadata(tupdesc);
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values = (char **) palloc(tupdesc->natts * sizeof(char *));
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while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
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{
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TM_Result htsu;
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@ -169,10 +164,6 @@ pgrowlocks(PG_FUNCTION_ARGS)
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*/
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if (htsu == TM_BeingModified)
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{
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char **values;
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values = (char **) palloc(mydata->ncolumns * sizeof(char *));
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values[Atnum_tid] = (char *) DirectFunctionCall1(tidout,
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PointerGetDatum(&tuple->t_self));
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@ -297,16 +288,7 @@ pgrowlocks(PG_FUNCTION_ARGS)
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/* build a tuple */
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tuple = BuildTupleFromCStrings(attinmeta, values);
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/* make the tuple into a datum */
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result = HeapTupleGetDatum(tuple);
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/*
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* no need to pfree what we allocated; it's on a short-lived
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* memory context anyway
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*/
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SRF_RETURN_NEXT(funcctx, result);
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tuplestore_puttuple(tupstore, tuple);
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}
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else
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{
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@ -315,7 +297,6 @@ pgrowlocks(PG_FUNCTION_ARGS)
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}
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table_endscan(scan);
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table_close(mydata->rel, AccessShareLock);
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SRF_RETURN_DONE(funcctx);
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table_close(rel, AccessShareLock);
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return (Datum) 0;
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}
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