/*------------------------------------------------------------------------- * * functions.c * Execution of SQL-language functions * * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * src/backend/executor/functions.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/htup_details.h" #include "access/xact.h" #include "catalog/pg_proc.h" #include "catalog/pg_type.h" #include "executor/functions.h" #include "funcapi.h" #include "miscadmin.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "parser/parse_coerce.h" #include "parser/parse_collate.h" #include "parser/parse_func.h" #include "rewrite/rewriteHandler.h" #include "storage/proc.h" #include "tcop/utility.h" #include "utils/builtins.h" #include "utils/datum.h" #include "utils/funccache.h" #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/plancache.h" #include "utils/snapmgr.h" #include "utils/syscache.h" /* * Specialized DestReceiver for collecting query output in a SQL function */ typedef struct { DestReceiver pub; /* publicly-known function pointers */ Tuplestorestate *tstore; /* where to put result tuples, or NULL */ JunkFilter *filter; /* filter to convert tuple type */ } DR_sqlfunction; /* * We have an execution_state record for each query in a function. Each * record references a plantree for its query. If the query is currently in * F_EXEC_RUN state then there's a QueryDesc too. * * The "next" fields chain together all the execution_state records generated * from a single original parsetree. (There will only be more than one in * case of rule expansion of the original parsetree.) The chain structure is * quite vestigial at this point, because we allocate the records in an array * for ease of memory management. But we'll get rid of it some other day. */ typedef enum { F_EXEC_START, F_EXEC_RUN, F_EXEC_DONE, } ExecStatus; typedef struct execution_state { struct execution_state *next; ExecStatus status; bool setsResult; /* true if this query produces func's result */ bool lazyEval; /* true if should fetch one row at a time */ PlannedStmt *stmt; /* plan for this query */ QueryDesc *qd; /* null unless status == RUN */ } execution_state; /* * Data associated with a SQL-language function is kept in two main * data structures: * * 1. SQLFunctionHashEntry is a long-lived (potentially session-lifespan) * struct that holds all the info we need out of the function's pg_proc row. * In addition it holds pointers to CachedPlanSource(s) that manage creation * of plans for the query(s) within the function. A SQLFunctionHashEntry is * potentially shared across multiple concurrent executions of the function, * so it must contain no execution-specific state; but its use_count must * reflect the number of SQLFunctionCache structs pointing at it. * If the function's pg_proc row is updated, we throw away and regenerate * the SQLFunctionHashEntry and subsidiary data. (Also note that if the * function is polymorphic or used as a trigger, there is a separate * SQLFunctionHashEntry for each usage, so that we need consider only one * set of relevant data types.) The struct itself is in memory managed by * funccache.c, and its subsidiary data is kept in one of two contexts: * * pcontext ("parse context") holds the raw parse trees or Query trees * that we read from the pg_proc row. These will be converted to * CachedPlanSources as they are needed. Once the last one is converted, * pcontext can be freed. * * hcontext ("hash context") holds everything else belonging to the * SQLFunctionHashEntry. * * 2. SQLFunctionCache is subsidiary data for a single FmgrInfo struct. * It is pointed to by the fn_extra field of the FmgrInfo struct, and is * always allocated in the FmgrInfo's fn_mcxt. It holds a reference to * the CachedPlan for the current query, and other execution-specific data. * A few subsidiary items such as the ParamListInfo object are also kept * directly in fn_mcxt (which is also called fcontext here). But most * subsidiary data is in jfcontext or subcontext. */ typedef struct SQLFunctionHashEntry { CachedFunction cfunc; /* fields managed by funccache.c */ char *fname; /* function name (for error msgs) */ char *src; /* function body text (for error msgs) */ SQLFunctionParseInfoPtr pinfo; /* data for parser callback hooks */ int16 *argtyplen; /* lengths of the input argument types */ Oid rettype; /* actual return type */ int16 typlen; /* length of the return type */ bool typbyval; /* true if return type is pass by value */ bool returnsSet; /* true if returning multiple rows */ bool returnsTuple; /* true if returning whole tuple result */ bool readonly_func; /* true to run in "read only" mode */ char prokind; /* prokind from pg_proc row */ TupleDesc rettupdesc; /* result tuple descriptor */ List *source_list; /* RawStmts or Queries read from pg_proc */ int num_queries; /* original length of source_list */ bool raw_source; /* true if source_list contains RawStmts */ List *plansource_list; /* CachedPlanSources for fn's queries */ MemoryContext pcontext; /* memory context holding source_list */ MemoryContext hcontext; /* memory context holding all else */ } SQLFunctionHashEntry; typedef struct SQLFunctionCache { SQLFunctionHashEntry *func; /* associated SQLFunctionHashEntry */ bool lazyEvalOK; /* true if lazyEval is safe */ bool shutdown_reg; /* true if registered shutdown callback */ bool lazyEval; /* true if using lazyEval for result query */ bool randomAccess; /* true if tstore needs random access */ bool ownSubcontext; /* is subcontext really a separate context? */ ParamListInfo paramLI; /* Param list representing current args */ Tuplestorestate *tstore; /* where we accumulate result for a SRF */ MemoryContext tscontext; /* memory context that tstore should be in */ JunkFilter *junkFilter; /* will be NULL if function returns VOID */ int jf_generation; /* tracks whether junkFilter is up-to-date */ /* * While executing a particular query within the function, cplan is the * CachedPlan we've obtained for that query, and eslist is a chain of * execution_state records for the individual plans within the CachedPlan. * If eslist is not NULL at entry to fmgr_sql, then we are resuming * execution of a lazyEval-mode set-returning function. * * next_query_index is the 0-based index of the next CachedPlanSource to * get a CachedPlan from. */ CachedPlan *cplan; /* Plan for current query, if any */ ResourceOwner cowner; /* CachedPlan is registered with this owner */ int next_query_index; /* index of next CachedPlanSource to run */ execution_state *eslist; /* chain of execution_state records */ execution_state *esarray; /* storage for eslist */ int esarray_len; /* allocated length of esarray[] */ /* if positive, this is the 1-based index of the query we're processing */ int error_query_index; MemoryContext fcontext; /* memory context holding this struct and all * subsidiary data */ MemoryContext jfcontext; /* subsidiary memory context holding * junkFilter, result slot, and related data */ MemoryContext subcontext; /* subsidiary memory context for sub-executor */ /* Callback to release our use-count on the SQLFunctionHashEntry */ MemoryContextCallback mcb; } SQLFunctionCache; typedef SQLFunctionCache *SQLFunctionCachePtr; /* non-export function prototypes */ static Node *sql_fn_param_ref(ParseState *pstate, ParamRef *pref); static Node *sql_fn_post_column_ref(ParseState *pstate, ColumnRef *cref, Node *var); static Node *sql_fn_make_param(SQLFunctionParseInfoPtr pinfo, int paramno, int location); static Node *sql_fn_resolve_param_name(SQLFunctionParseInfoPtr pinfo, const char *paramname, int location); static SQLFunctionCache *init_sql_fcache(FunctionCallInfo fcinfo, bool lazyEvalOK); static bool init_execution_state(SQLFunctionCachePtr fcache); static void prepare_next_query(SQLFunctionHashEntry *func); static void sql_compile_callback(FunctionCallInfo fcinfo, HeapTuple procedureTuple, const CachedFunctionHashKey *hashkey, CachedFunction *cfunc, bool forValidator); static void sql_delete_callback(CachedFunction *cfunc); static void sql_postrewrite_callback(List *querytree_list, void *arg); static void postquel_start(execution_state *es, SQLFunctionCachePtr fcache); static bool postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache); static void postquel_end(execution_state *es, SQLFunctionCachePtr fcache); static void postquel_sub_params(SQLFunctionCachePtr fcache, FunctionCallInfo fcinfo); static Datum postquel_get_single_result(TupleTableSlot *slot, FunctionCallInfo fcinfo, SQLFunctionCachePtr fcache); static void sql_compile_error_callback(void *arg); static void sql_exec_error_callback(void *arg); static void ShutdownSQLFunction(Datum arg); static void RemoveSQLFunctionCache(void *arg); static void check_sql_fn_statement(List *queryTreeList); static bool check_sql_stmt_retval(List *queryTreeList, Oid rettype, TupleDesc rettupdesc, char prokind, bool insertDroppedCols); static bool coerce_fn_result_column(TargetEntry *src_tle, Oid res_type, int32 res_typmod, bool tlist_is_modifiable, List **upper_tlist, bool *upper_tlist_nontrivial); static List *get_sql_fn_result_tlist(List *queryTreeList); static void sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo); static bool sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self); static void sqlfunction_shutdown(DestReceiver *self); static void sqlfunction_destroy(DestReceiver *self); /* * Prepare the SQLFunctionParseInfo struct for parsing a SQL function body * * This includes resolving actual types of polymorphic arguments. * * call_expr can be passed as NULL, but then we will fail if there are any * polymorphic arguments. */ SQLFunctionParseInfoPtr prepare_sql_fn_parse_info(HeapTuple procedureTuple, Node *call_expr, Oid inputCollation) { SQLFunctionParseInfoPtr pinfo; Form_pg_proc procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple); int nargs; pinfo = (SQLFunctionParseInfoPtr) palloc0(sizeof(SQLFunctionParseInfo)); /* Function's name (only) can be used to qualify argument names */ pinfo->fname = pstrdup(NameStr(procedureStruct->proname)); /* Save the function's input collation */ pinfo->collation = inputCollation; /* * Copy input argument types from the pg_proc entry, then resolve any * polymorphic types. */ pinfo->nargs = nargs = procedureStruct->pronargs; if (nargs > 0) { Oid *argOidVect; int argnum; argOidVect = (Oid *) palloc(nargs * sizeof(Oid)); memcpy(argOidVect, procedureStruct->proargtypes.values, nargs * sizeof(Oid)); for (argnum = 0; argnum < nargs; argnum++) { Oid argtype = argOidVect[argnum]; if (IsPolymorphicType(argtype)) { argtype = get_call_expr_argtype(call_expr, argnum); if (argtype == InvalidOid) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("could not determine actual type of argument declared %s", format_type_be(argOidVect[argnum])))); argOidVect[argnum] = argtype; } } pinfo->argtypes = argOidVect; } /* * Collect names of arguments, too, if any */ if (nargs > 0) { Datum proargnames; Datum proargmodes; int n_arg_names; bool isNull; proargnames = SysCacheGetAttr(PROCNAMEARGSNSP, procedureTuple, Anum_pg_proc_proargnames, &isNull); if (isNull) proargnames = PointerGetDatum(NULL); /* just to be sure */ proargmodes = SysCacheGetAttr(PROCNAMEARGSNSP, procedureTuple, Anum_pg_proc_proargmodes, &isNull); if (isNull) proargmodes = PointerGetDatum(NULL); /* just to be sure */ n_arg_names = get_func_input_arg_names(proargnames, proargmodes, &pinfo->argnames); /* Paranoia: ignore the result if too few array entries */ if (n_arg_names < nargs) pinfo->argnames = NULL; } else pinfo->argnames = NULL; return pinfo; } /* * Parser setup hook for parsing a SQL function body. */ void sql_fn_parser_setup(struct ParseState *pstate, SQLFunctionParseInfoPtr pinfo) { pstate->p_pre_columnref_hook = NULL; pstate->p_post_columnref_hook = sql_fn_post_column_ref; pstate->p_paramref_hook = sql_fn_param_ref; /* no need to use p_coerce_param_hook */ pstate->p_ref_hook_state = pinfo; } /* * sql_fn_post_column_ref parser callback for ColumnRefs */ static Node * sql_fn_post_column_ref(ParseState *pstate, ColumnRef *cref, Node *var) { SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state; int nnames; Node *field1; Node *subfield = NULL; const char *name1; const char *name2 = NULL; Node *param; /* * Never override a table-column reference. This corresponds to * considering the parameter names to appear in a scope outside the * individual SQL commands, which is what we want. */ if (var != NULL) return NULL; /*---------- * The allowed syntaxes are: * * A A = parameter name * A.B A = function name, B = parameter name * OR: A = record-typed parameter name, B = field name * (the first possibility takes precedence) * A.B.C A = function name, B = record-typed parameter name, * C = field name * A.* Whole-row reference to composite parameter A. * A.B.* Same, with A = function name, B = parameter name * * Here, it's sufficient to ignore the "*" in the last two cases --- the * main parser will take care of expanding the whole-row reference. *---------- */ nnames = list_length(cref->fields); if (nnames > 3) return NULL; if (IsA(llast(cref->fields), A_Star)) nnames--; field1 = (Node *) linitial(cref->fields); name1 = strVal(field1); if (nnames > 1) { subfield = (Node *) lsecond(cref->fields); name2 = strVal(subfield); } if (nnames == 3) { /* * Three-part name: if the first part doesn't match the function name, * we can fail immediately. Otherwise, look up the second part, and * take the third part to be a field reference. */ if (strcmp(name1, pinfo->fname) != 0) return NULL; param = sql_fn_resolve_param_name(pinfo, name2, cref->location); subfield = (Node *) lthird(cref->fields); Assert(IsA(subfield, String)); } else if (nnames == 2 && strcmp(name1, pinfo->fname) == 0) { /* * Two-part name with first part matching function name: first see if * second part matches any parameter name. */ param = sql_fn_resolve_param_name(pinfo, name2, cref->location); if (param) { /* Yes, so this is a parameter reference, no subfield */ subfield = NULL; } else { /* No, so try to match as parameter name and subfield */ param = sql_fn_resolve_param_name(pinfo, name1, cref->location); } } else { /* Single name, or parameter name followed by subfield */ param = sql_fn_resolve_param_name(pinfo, name1, cref->location); } if (!param) return NULL; /* No match */ if (subfield) { /* * Must be a reference to a field of a composite parameter; otherwise * ParseFuncOrColumn will return NULL, and we'll fail back at the * caller. */ param = ParseFuncOrColumn(pstate, list_make1(subfield), list_make1(param), pstate->p_last_srf, NULL, false, cref->location); } return param; } /* * sql_fn_param_ref parser callback for ParamRefs ($n symbols) */ static Node * sql_fn_param_ref(ParseState *pstate, ParamRef *pref) { SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state; int paramno = pref->number; /* Check parameter number is valid */ if (paramno <= 0 || paramno > pinfo->nargs) return NULL; /* unknown parameter number */ return sql_fn_make_param(pinfo, paramno, pref->location); } /* * sql_fn_make_param construct a Param node for the given paramno */ static Node * sql_fn_make_param(SQLFunctionParseInfoPtr pinfo, int paramno, int location) { Param *param; param = makeNode(Param); param->paramkind = PARAM_EXTERN; param->paramid = paramno; param->paramtype = pinfo->argtypes[paramno - 1]; param->paramtypmod = -1; param->paramcollid = get_typcollation(param->paramtype); param->location = location; /* * If we have a function input collation, allow it to override the * type-derived collation for parameter symbols. (XXX perhaps this should * not happen if the type collation is not default?) */ if (OidIsValid(pinfo->collation) && OidIsValid(param->paramcollid)) param->paramcollid = pinfo->collation; return (Node *) param; } /* * Search for a function parameter of the given name; if there is one, * construct and return a Param node for it. If not, return NULL. * Helper function for sql_fn_post_column_ref. */ static Node * sql_fn_resolve_param_name(SQLFunctionParseInfoPtr pinfo, const char *paramname, int location) { int i; if (pinfo->argnames == NULL) return NULL; for (i = 0; i < pinfo->nargs; i++) { if (pinfo->argnames[i] && strcmp(pinfo->argnames[i], paramname) == 0) return sql_fn_make_param(pinfo, i + 1, location); } return NULL; } /* * Initialize the SQLFunctionCache for a SQL function */ static SQLFunctionCache * init_sql_fcache(FunctionCallInfo fcinfo, bool lazyEvalOK) { FmgrInfo *finfo = fcinfo->flinfo; SQLFunctionHashEntry *func; SQLFunctionCache *fcache; /* * If this is the first execution for this FmgrInfo, set up a cache struct * (initially containing null pointers). The cache must live as long as * the FmgrInfo, so it goes in fn_mcxt. Also set up a memory context * callback that will be invoked when fn_mcxt is deleted. */ fcache = finfo->fn_extra; if (fcache == NULL) { fcache = (SQLFunctionCache *) MemoryContextAllocZero(finfo->fn_mcxt, sizeof(SQLFunctionCache)); fcache->fcontext = finfo->fn_mcxt; fcache->mcb.func = RemoveSQLFunctionCache; fcache->mcb.arg = fcache; MemoryContextRegisterResetCallback(finfo->fn_mcxt, &fcache->mcb); finfo->fn_extra = fcache; } /* * If we are resuming execution of a set-returning function, just keep * using the same cache. We do not ask funccache.c to re-validate the * SQLFunctionHashEntry: we want to run to completion using the function's * initial definition. */ if (fcache->eslist != NULL) { Assert(fcache->func != NULL); return fcache; } /* * Look up, or re-validate, the long-lived hash entry. Make the hash key * depend on the result of get_call_result_type() when that's composite, * so that we can safely assume that we'll build a new hash entry if the * composite rowtype changes. */ func = (SQLFunctionHashEntry *) cached_function_compile(fcinfo, (CachedFunction *) fcache->func, sql_compile_callback, sql_delete_callback, sizeof(SQLFunctionHashEntry), true, false); /* * Install the hash pointer in the SQLFunctionCache, and increment its use * count to reflect that. If cached_function_compile gave us back a * different hash entry than we were using before, we must decrement that * one's use count. */ if (func != fcache->func) { if (fcache->func != NULL) { Assert(fcache->func->cfunc.use_count > 0); fcache->func->cfunc.use_count--; } fcache->func = func; func->cfunc.use_count++; /* Assume we need to rebuild the junkFilter */ fcache->junkFilter = NULL; } /* * We're beginning a new execution of the function, so convert params to * appropriate format. */ postquel_sub_params(fcache, fcinfo); /* Also reset lazyEval state for the new execution. */ fcache->lazyEvalOK = lazyEvalOK; fcache->lazyEval = false; /* Also reset data about where we are in the function. */ fcache->eslist = NULL; fcache->next_query_index = 0; fcache->error_query_index = 0; return fcache; } /* * Set up the per-query execution_state records for the next query within * the SQL function. * * Returns true if successful, false if there are no more queries. */ static bool init_execution_state(SQLFunctionCachePtr fcache) { CachedPlanSource *plansource; execution_state *preves = NULL; execution_state *lasttages = NULL; int nstmts; ListCell *lc; /* * Clean up after previous query, if there was one. */ if (fcache->cplan) { ReleaseCachedPlan(fcache->cplan, fcache->cowner); fcache->cplan = NULL; } fcache->eslist = NULL; /* * Get the next CachedPlanSource, or stop if there are no more. We might * need to create the next CachedPlanSource; if so, advance * error_query_index first, so that errors detected in prepare_next_query * are blamed on the right statement. */ if (fcache->next_query_index >= list_length(fcache->func->plansource_list)) { if (fcache->next_query_index >= fcache->func->num_queries) return false; fcache->error_query_index++; prepare_next_query(fcache->func); } else fcache->error_query_index++; plansource = (CachedPlanSource *) list_nth(fcache->func->plansource_list, fcache->next_query_index); fcache->next_query_index++; /* * Generate plans for the query or queries within this CachedPlanSource. * Register the CachedPlan with the current resource owner. (Saving * cowner here is mostly paranoia, but this way we needn't assume that * CurrentResourceOwner will be the same when ShutdownSQLFunction runs.) */ fcache->cowner = CurrentResourceOwner; fcache->cplan = GetCachedPlan(plansource, fcache->paramLI, fcache->cowner, NULL); /* * If necessary, make esarray[] bigger to hold the needed state. */ nstmts = list_length(fcache->cplan->stmt_list); if (nstmts > fcache->esarray_len) { if (fcache->esarray == NULL) fcache->esarray = (execution_state *) MemoryContextAlloc(fcache->fcontext, sizeof(execution_state) * nstmts); else fcache->esarray = repalloc_array(fcache->esarray, execution_state, nstmts); fcache->esarray_len = nstmts; } /* * Build execution_state list to match the number of contained plans. */ foreach(lc, fcache->cplan->stmt_list) { PlannedStmt *stmt = lfirst_node(PlannedStmt, lc); execution_state *newes; /* * Precheck all commands for validity in a function. This should * generally match the restrictions spi.c applies. */ if (stmt->commandType == CMD_UTILITY) { if (IsA(stmt->utilityStmt, CopyStmt) && ((CopyStmt *) stmt->utilityStmt)->filename == NULL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot COPY to/from client in an SQL function"))); if (IsA(stmt->utilityStmt, TransactionStmt)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), /* translator: %s is a SQL statement name */ errmsg("%s is not allowed in an SQL function", CreateCommandName(stmt->utilityStmt)))); } if (fcache->func->readonly_func && !CommandIsReadOnly(stmt)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), /* translator: %s is a SQL statement name */ errmsg("%s is not allowed in a non-volatile function", CreateCommandName((Node *) stmt)))); /* OK, build the execution_state for this query */ newes = &fcache->esarray[foreach_current_index(lc)]; if (preves) preves->next = newes; else fcache->eslist = newes; newes->next = NULL; newes->status = F_EXEC_START; newes->setsResult = false; /* might change below */ newes->lazyEval = false; /* might change below */ newes->stmt = stmt; newes->qd = NULL; if (stmt->canSetTag) lasttages = newes; preves = newes; } /* * If this isn't the last CachedPlanSource, we're done here. Otherwise, * we need to prepare information about how to return the results. */ if (fcache->next_query_index < fcache->func->num_queries) return true; /* * Construct a JunkFilter we can use to coerce the returned rowtype to the * desired form, unless the result type is VOID, in which case there's * nothing to coerce to. (XXX Frequently, the JunkFilter isn't doing * anything very interesting, but much of this module expects it to be * there anyway.) * * Normally we can re-use the JunkFilter across executions, but if the * plan for the last CachedPlanSource changed, we'd better rebuild it. * * The JunkFilter, its result slot, and its tupledesc are kept in a * subsidiary memory context so that we can free them easily when needed. */ if (fcache->func->rettype != VOIDOID && (fcache->junkFilter == NULL || fcache->jf_generation != fcache->cplan->generation)) { TupleTableSlot *slot; List *resulttlist; MemoryContext oldcontext; /* Create or reset the jfcontext */ if (fcache->jfcontext == NULL) fcache->jfcontext = AllocSetContextCreate(fcache->fcontext, "SQL function junkfilter", ALLOCSET_SMALL_SIZES); else MemoryContextReset(fcache->jfcontext); oldcontext = MemoryContextSwitchTo(fcache->jfcontext); slot = MakeSingleTupleTableSlot(NULL, &TTSOpsMinimalTuple); /* * Re-fetch the (possibly modified) output tlist of the final * statement. By this point, we should have thrown an error if there * is not one. */ resulttlist = get_sql_fn_result_tlist(plansource->query_list); /* * If the result is composite, *and* we are returning the whole tuple * result, we need to insert nulls for any dropped columns. In the * single-column-result case, there might be dropped columns within * the composite column value, but it's not our problem here. There * should be no resjunk entries in resulttlist, so in the second case * the JunkFilter is certainly a no-op. */ if (fcache->func->rettupdesc && fcache->func->returnsTuple) fcache->junkFilter = ExecInitJunkFilterConversion(resulttlist, fcache->func->rettupdesc, slot); else fcache->junkFilter = ExecInitJunkFilter(resulttlist, slot); /* * The resulttlist tree belongs to the plancache and might disappear * underneath us due to plancache invalidation. While we could * forestall that by copying it, that'd just be a waste of cycles, * because the junkfilter doesn't need it anymore. (It'd only be used * by ExecFindJunkAttribute(), which we don't use here.) To ensure * there's not a dangling pointer laying about, clear the junkFilter's * pointer. */ fcache->junkFilter->jf_targetList = NIL; /* Make sure output rowtype is properly blessed */ if (fcache->func->returnsTuple) BlessTupleDesc(fcache->junkFilter->jf_resultSlot->tts_tupleDescriptor); /* Mark the JunkFilter as up-to-date */ fcache->jf_generation = fcache->cplan->generation; MemoryContextSwitchTo(oldcontext); } if (fcache->func->returnsSet && !fcache->func->returnsTuple && type_is_rowtype(fcache->func->rettype)) { /* * Returning rowtype as if it were scalar --- materialize won't work. * Right now it's sufficient to override any caller preference for * materialize mode, but this might need more work in future. */ fcache->lazyEvalOK = true; } /* * Mark the last canSetTag query as delivering the function result; then, * if it is a plain SELECT, mark it for lazy evaluation. If it's not a * SELECT we must always run it to completion. * * Note: at some point we might add additional criteria for whether to use * lazy eval. However, we should prefer to use it whenever the function * doesn't return set, since fetching more than one row is useless in that * case. * * Note: don't set setsResult if the function returns VOID, as evidenced * by not having made a junkfilter. This ensures we'll throw away any * output from the last statement in such a function. */ if (lasttages && fcache->junkFilter) { lasttages->setsResult = true; if (fcache->lazyEvalOK && lasttages->stmt->commandType == CMD_SELECT && !lasttages->stmt->hasModifyingCTE) fcache->lazyEval = lasttages->lazyEval = true; } return true; } /* * Convert the SQL function's next query from source form (RawStmt or Query) * into a CachedPlanSource. If it's the last query, also determine whether * the function returnsTuple. */ static void prepare_next_query(SQLFunctionHashEntry *func) { int qindex; bool islast; CachedPlanSource *plansource; List *queryTree_list; MemoryContext oldcontext; /* Which query should we process? */ qindex = list_length(func->plansource_list); Assert(qindex < func->num_queries); /* else caller error */ islast = (qindex + 1 >= func->num_queries); /* * Parse and/or rewrite the query, creating a CachedPlanSource that holds * a copy of the original parsetree. Note fine point: we make a copy of * each original parsetree to ensure that the source_list in pcontext * remains unmodified during parse analysis and rewrite. This is normally * unnecessary, but we have to do it in case an error is raised during * parse analysis. Otherwise, a fresh attempt to execute the function * will arrive back here and try to work from a corrupted source_list. */ if (!func->raw_source) { /* Source queries are already parse-analyzed */ Query *parsetree = list_nth_node(Query, func->source_list, qindex); parsetree = copyObject(parsetree); plansource = CreateCachedPlanForQuery(parsetree, func->src, CreateCommandTag((Node *) parsetree)); AcquireRewriteLocks(parsetree, true, false); queryTree_list = pg_rewrite_query(parsetree); } else { /* Source queries are raw parsetrees */ RawStmt *parsetree = list_nth_node(RawStmt, func->source_list, qindex); parsetree = copyObject(parsetree); plansource = CreateCachedPlan(parsetree, func->src, CreateCommandTag(parsetree->stmt)); queryTree_list = pg_analyze_and_rewrite_withcb(parsetree, func->src, (ParserSetupHook) sql_fn_parser_setup, func->pinfo, NULL); } /* * Check that there are no statements we don't want to allow. */ check_sql_fn_statement(queryTree_list); /* * If this is the last query, check that the function returns the type it * claims to. Although in simple cases this was already done when the * function was defined, we have to recheck because database objects used * in the function's queries might have changed type. We'd have to * recheck anyway if the function had any polymorphic arguments. Moreover, * check_sql_stmt_retval takes care of injecting any required column type * coercions. (But we don't ask it to insert nulls for dropped columns; * the junkfilter handles that.) * * Note: we set func->returnsTuple according to whether we are returning * the whole tuple result or just a single column. In the latter case we * clear returnsTuple because we need not act different from the scalar * result case, even if it's a rowtype column. (However, we have to force * lazy eval mode in that case; otherwise we'd need extra code to expand * the rowtype column into multiple columns, since we have no way to * notify the caller that it should do that.) */ if (islast) func->returnsTuple = check_sql_stmt_retval(queryTree_list, func->rettype, func->rettupdesc, func->prokind, false); /* * Now that check_sql_stmt_retval has done its thing, we can complete plan * cache entry creation. */ CompleteCachedPlan(plansource, queryTree_list, NULL, NULL, 0, (ParserSetupHook) sql_fn_parser_setup, func->pinfo, CURSOR_OPT_PARALLEL_OK | CURSOR_OPT_NO_SCROLL, false); /* * Install post-rewrite hook. Its arg is the hash entry if this is the * last statement, else NULL. */ SetPostRewriteHook(plansource, sql_postrewrite_callback, islast ? func : NULL); /* * While the CachedPlanSources can take care of themselves, our List * pointing to them had better be in the hcontext. */ oldcontext = MemoryContextSwitchTo(func->hcontext); func->plansource_list = lappend(func->plansource_list, plansource); MemoryContextSwitchTo(oldcontext); /* * As soon as we've linked the CachedPlanSource into the list, mark it as * "saved". */ SaveCachedPlan(plansource); /* * Finally, if this was the last statement, we can flush the pcontext with * the original query trees; they're all safely copied into * CachedPlanSources now. */ if (islast) { func->source_list = NIL; /* avoid dangling pointer */ MemoryContextDelete(func->pcontext); func->pcontext = NULL; } } /* * Fill a new SQLFunctionHashEntry. * * The passed-in "cfunc" struct is expected to be zeroes, except * for the CachedFunction fields, which we don't touch here. * * We expect to be called in a short-lived memory context (typically a * query's per-tuple context). Data that is to be part of the hash entry * must be copied into the hcontext or pcontext as appropriate. */ static void sql_compile_callback(FunctionCallInfo fcinfo, HeapTuple procedureTuple, const CachedFunctionHashKey *hashkey, CachedFunction *cfunc, bool forValidator) { SQLFunctionHashEntry *func = (SQLFunctionHashEntry *) cfunc; Form_pg_proc procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple); ErrorContextCallback comperrcontext; MemoryContext hcontext; MemoryContext pcontext; MemoryContext oldcontext = CurrentMemoryContext; Oid rettype; TupleDesc rettupdesc; Datum tmp; bool isNull; List *source_list; /* * Setup error traceback support for ereport() during compile. (This is * mainly useful for reporting parse errors from pg_parse_query.) */ comperrcontext.callback = sql_compile_error_callback; comperrcontext.arg = func; comperrcontext.previous = error_context_stack; error_context_stack = &comperrcontext; /* * Create the hash entry's memory context. For now it's a child of the * caller's context, so that it will go away if we fail partway through. */ hcontext = AllocSetContextCreate(CurrentMemoryContext, "SQL function", ALLOCSET_SMALL_SIZES); /* * Create the not-as-long-lived pcontext. We make this a child of * hcontext so that it doesn't require separate deletion. */ pcontext = AllocSetContextCreate(hcontext, "SQL function parse trees", ALLOCSET_SMALL_SIZES); func->pcontext = pcontext; /* * copy function name immediately for use by error reporting callback, and * for use as memory context identifier */ func->fname = MemoryContextStrdup(hcontext, NameStr(procedureStruct->proname)); MemoryContextSetIdentifier(hcontext, func->fname); /* * Resolve any polymorphism, obtaining the actual result type, and the * corresponding tupdesc if it's a rowtype. */ (void) get_call_result_type(fcinfo, &rettype, &rettupdesc); func->rettype = rettype; if (rettupdesc) { MemoryContextSwitchTo(hcontext); func->rettupdesc = CreateTupleDescCopy(rettupdesc); MemoryContextSwitchTo(oldcontext); } /* Fetch the typlen and byval info for the result type */ get_typlenbyval(rettype, &func->typlen, &func->typbyval); /* Remember whether we're returning setof something */ func->returnsSet = procedureStruct->proretset; /* Remember if function is STABLE/IMMUTABLE */ func->readonly_func = (procedureStruct->provolatile != PROVOLATILE_VOLATILE); /* Remember routine kind */ func->prokind = procedureStruct->prokind; /* * We need the actual argument types to pass to the parser. Also make * sure that parameter symbols are considered to have the function's * resolved input collation. */ MemoryContextSwitchTo(hcontext); func->pinfo = prepare_sql_fn_parse_info(procedureTuple, fcinfo->flinfo->fn_expr, PG_GET_COLLATION()); MemoryContextSwitchTo(oldcontext); /* * Now that we have the resolved argument types, collect their typlens for * use in postquel_sub_params. */ func->argtyplen = (int16 *) MemoryContextAlloc(hcontext, func->pinfo->nargs * sizeof(int16)); for (int i = 0; i < func->pinfo->nargs; i++) func->argtyplen[i] = get_typlen(func->pinfo->argtypes[i]); /* * And of course we need the function body text. */ tmp = SysCacheGetAttrNotNull(PROCOID, procedureTuple, Anum_pg_proc_prosrc); func->src = MemoryContextStrdup(hcontext, TextDatumGetCString(tmp)); /* If we have prosqlbody, pay attention to that not prosrc. */ tmp = SysCacheGetAttr(PROCOID, procedureTuple, Anum_pg_proc_prosqlbody, &isNull); if (!isNull) { /* Source queries are already parse-analyzed */ Node *n; n = stringToNode(TextDatumGetCString(tmp)); if (IsA(n, List)) source_list = linitial_node(List, castNode(List, n)); else source_list = list_make1(n); func->raw_source = false; } else { /* Source queries are raw parsetrees */ source_list = pg_parse_query(func->src); func->raw_source = true; } /* * Note: we must save the number of queries so that we'll still remember * how many there are after we discard source_list. */ func->num_queries = list_length(source_list); /* * Edge case: empty function body is OK only if it returns VOID. Normally * we validate that the last statement returns the right thing in * check_sql_stmt_retval, but we'll never reach that if there's no last * statement. */ if (func->num_queries == 0 && rettype != VOIDOID) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type mismatch in function declared to return %s", format_type_be(rettype)), errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE/MERGE RETURNING."))); /* Save the source trees in pcontext for now. */ MemoryContextSwitchTo(pcontext); func->source_list = copyObject(source_list); MemoryContextSwitchTo(oldcontext); /* * We now have a fully valid hash entry, so reparent hcontext under * CacheMemoryContext to make all the subsidiary data long-lived, and only * then install the hcontext link so that sql_delete_callback will know to * delete it. */ MemoryContextSetParent(hcontext, CacheMemoryContext); func->hcontext = hcontext; error_context_stack = comperrcontext.previous; } /* * Deletion callback used by funccache.c. * * Free any free-able subsidiary data of cfunc, but not the * struct CachedFunction itself. */ static void sql_delete_callback(CachedFunction *cfunc) { SQLFunctionHashEntry *func = (SQLFunctionHashEntry *) cfunc; ListCell *lc; /* Release the CachedPlanSources */ foreach(lc, func->plansource_list) { CachedPlanSource *plansource = (CachedPlanSource *) lfirst(lc); DropCachedPlan(plansource); } func->plansource_list = NIL; /* * If we have an hcontext, free it, thereby getting rid of all subsidiary * data. (If we still have a pcontext, this gets rid of that too.) */ if (func->hcontext) MemoryContextDelete(func->hcontext); func->hcontext = NULL; } /* * Post-rewrite callback used by plancache.c. * * This must match the processing that prepare_next_query() does between * rewriting and calling CompleteCachedPlan(). */ static void sql_postrewrite_callback(List *querytree_list, void *arg) { /* * Check that there are no statements we don't want to allow. (Presently, * there's no real point in this because the result can't change from what * we saw originally. But it's cheap and maybe someday it will matter.) */ check_sql_fn_statement(querytree_list); /* * If this is the last query, we must re-do what check_sql_stmt_retval did * to its targetlist. Also check that returnsTuple didn't change (it * probably cannot, but be cautious). */ if (arg != NULL) { SQLFunctionHashEntry *func = (SQLFunctionHashEntry *) arg; bool returnsTuple; returnsTuple = check_sql_stmt_retval(querytree_list, func->rettype, func->rettupdesc, func->prokind, false); if (returnsTuple != func->returnsTuple) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cached plan must not change result type"))); } } /* Start up execution of one execution_state node */ static void postquel_start(execution_state *es, SQLFunctionCachePtr fcache) { DestReceiver *dest; MemoryContext oldcontext = CurrentMemoryContext; Assert(es->qd == NULL); /* Caller should have ensured a suitable snapshot is active */ Assert(ActiveSnapshotSet()); /* * In lazyEval mode for a SRF, we must run the sub-executor in a child of * fcontext, so that it can survive across multiple calls to fmgr_sql. * (XXX in the case of a long-lived FmgrInfo, this policy potentially * causes memory leakage, but it's not very clear where we could keep * stuff instead. Fortunately, there are few if any cases where * set-returning functions are invoked via FmgrInfos that would outlive * the calling query.) Otherwise, we're going to run it to completion * before exiting fmgr_sql, so it can perfectly well run in the caller's * context. */ if (es->lazyEval && fcache->func->returnsSet) { fcache->subcontext = AllocSetContextCreate(fcache->fcontext, "SQL function execution", ALLOCSET_DEFAULT_SIZES); fcache->ownSubcontext = true; } else if (es->stmt->commandType == CMD_UTILITY) { /* * The code path using a sub-executor is pretty good about cleaning up * cruft, since the executor will make its own sub-context. We don't * really need an additional layer of sub-context in that case. * However, if this is a utility statement, it won't make its own * sub-context, so it seems advisable to make one that we can free on * completion. */ fcache->subcontext = AllocSetContextCreate(CurrentMemoryContext, "SQL function execution", ALLOCSET_DEFAULT_SIZES); fcache->ownSubcontext = true; } else { fcache->subcontext = CurrentMemoryContext; fcache->ownSubcontext = false; } /* * Build a tuplestore if needed, that is if it's a set-returning function * and we're producing the function result without using lazyEval mode. */ if (es->setsResult) { Assert(fcache->tstore == NULL); if (fcache->func->returnsSet && !es->lazyEval) { MemoryContextSwitchTo(fcache->tscontext); fcache->tstore = tuplestore_begin_heap(fcache->randomAccess, false, work_mem); } } /* Switch into the selected subcontext (might be a no-op) */ MemoryContextSwitchTo(fcache->subcontext); /* * If this query produces the function result, collect its output using * our custom DestReceiver; else discard any output. */ if (es->setsResult) { DR_sqlfunction *myState; dest = CreateDestReceiver(DestSQLFunction); /* pass down the needed info to the dest receiver routines */ myState = (DR_sqlfunction *) dest; Assert(myState->pub.mydest == DestSQLFunction); myState->tstore = fcache->tstore; /* might be NULL */ myState->filter = fcache->junkFilter; /* Make very sure the junkfilter's result slot is empty */ ExecClearTuple(fcache->junkFilter->jf_resultSlot); } else dest = None_Receiver; es->qd = CreateQueryDesc(es->stmt, fcache->func->src, GetActiveSnapshot(), InvalidSnapshot, dest, fcache->paramLI, es->qd ? es->qd->queryEnv : NULL, 0); /* Utility commands don't need Executor. */ if (es->qd->operation != CMD_UTILITY) { /* * In lazyEval mode, do not let the executor set up an AfterTrigger * context. This is necessary not just an optimization, because we * mustn't exit from the function execution with a stacked * AfterTrigger level still active. We are careful not to select * lazyEval mode for any statement that could possibly queue triggers. */ int eflags; if (es->lazyEval) eflags = EXEC_FLAG_SKIP_TRIGGERS; else eflags = 0; /* default run-to-completion flags */ ExecutorStart(es->qd, eflags); } es->status = F_EXEC_RUN; MemoryContextSwitchTo(oldcontext); } /* Run one execution_state; either to completion or to first result row */ /* Returns true if we ran to completion */ static bool postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache) { bool result; MemoryContext oldcontext; /* Run the sub-executor in subcontext */ oldcontext = MemoryContextSwitchTo(fcache->subcontext); if (es->qd->operation == CMD_UTILITY) { ProcessUtility(es->qd->plannedstmt, fcache->func->src, true, /* protect function cache's parsetree */ PROCESS_UTILITY_QUERY, es->qd->params, es->qd->queryEnv, es->qd->dest, NULL); result = true; /* never stops early */ } else { /* Run regular commands to completion unless lazyEval */ uint64 count = (es->lazyEval) ? 1 : 0; ExecutorRun(es->qd, ForwardScanDirection, count); /* * If we requested run to completion OR there was no tuple returned, * command must be complete. */ result = (count == 0 || es->qd->estate->es_processed == 0); } MemoryContextSwitchTo(oldcontext); return result; } /* Shut down execution of one execution_state node */ static void postquel_end(execution_state *es, SQLFunctionCachePtr fcache) { MemoryContext oldcontext; /* Run the sub-executor in subcontext */ oldcontext = MemoryContextSwitchTo(fcache->subcontext); /* mark status done to ensure we don't do ExecutorEnd twice */ es->status = F_EXEC_DONE; /* Utility commands don't need Executor. */ if (es->qd->operation != CMD_UTILITY) { ExecutorFinish(es->qd); ExecutorEnd(es->qd); } es->qd->dest->rDestroy(es->qd->dest); FreeQueryDesc(es->qd); es->qd = NULL; MemoryContextSwitchTo(oldcontext); /* Delete the subcontext, if it's actually a separate context */ if (fcache->ownSubcontext) MemoryContextDelete(fcache->subcontext); fcache->subcontext = NULL; } /* Build ParamListInfo array representing current arguments */ static void postquel_sub_params(SQLFunctionCachePtr fcache, FunctionCallInfo fcinfo) { int nargs = fcinfo->nargs; if (nargs > 0) { ParamListInfo paramLI; Oid *argtypes = fcache->func->pinfo->argtypes; int16 *argtyplen = fcache->func->argtyplen; if (fcache->paramLI == NULL) { /* First time through: build a persistent ParamListInfo struct */ MemoryContext oldcontext; oldcontext = MemoryContextSwitchTo(fcache->fcontext); paramLI = makeParamList(nargs); fcache->paramLI = paramLI; MemoryContextSwitchTo(oldcontext); } else { paramLI = fcache->paramLI; Assert(paramLI->numParams == nargs); } for (int i = 0; i < nargs; i++) { ParamExternData *prm = ¶mLI->params[i]; /* * If an incoming parameter value is a R/W expanded datum, we * force it to R/O. We'd be perfectly entitled to scribble on it, * but the problem is that if the parameter is referenced more * than once in the function, earlier references might mutate the * value seen by later references, which won't do at all. We * could do better if we could be sure of the number of Param * nodes in the function's plans; but we might not have planned * all the statements yet, nor do we have plan tree walker * infrastructure. (Examining the parse trees is not good enough, * because of possible function inlining during planning.) */ prm->isnull = fcinfo->args[i].isnull; prm->value = MakeExpandedObjectReadOnly(fcinfo->args[i].value, prm->isnull, argtyplen[i]); /* Allow the value to be substituted into custom plans */ prm->pflags = PARAM_FLAG_CONST; prm->ptype = argtypes[i]; } } else fcache->paramLI = NULL; } /* * Extract the SQL function's value from a single result row. This is used * both for scalar (non-set) functions and for each row of a lazy-eval set * result. We expect the current memory context to be that of the caller * of fmgr_sql. */ static Datum postquel_get_single_result(TupleTableSlot *slot, FunctionCallInfo fcinfo, SQLFunctionCachePtr fcache) { Datum value; /* * Set up to return the function value. For pass-by-reference datatypes, * be sure to copy the result into the current context. We can't leave * the data in the TupleTableSlot because we must clear the slot before * returning. */ if (fcache->func->returnsTuple) { /* We must return the whole tuple as a Datum. */ fcinfo->isnull = false; value = ExecFetchSlotHeapTupleDatum(slot); } else { /* * Returning a scalar, which we have to extract from the first column * of the SELECT result, and then copy into current context if needed. */ value = slot_getattr(slot, 1, &(fcinfo->isnull)); if (!fcinfo->isnull) value = datumCopy(value, fcache->func->typbyval, fcache->func->typlen); } /* Clear the slot for next time */ ExecClearTuple(slot); return value; } /* * fmgr_sql: function call manager for SQL functions */ Datum fmgr_sql(PG_FUNCTION_ARGS) { SQLFunctionCachePtr fcache; ErrorContextCallback sqlerrcontext; MemoryContext tscontext; bool randomAccess; bool lazyEvalOK; bool pushed_snapshot; execution_state *es; TupleTableSlot *slot; Datum result; /* Check call context */ if (fcinfo->flinfo->fn_retset) { ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo; /* * For simplicity, we require callers to support both set eval modes. * There are cases where we must use one or must use the other, and * it's not really worthwhile to postpone the check till we know. But * note we do not require caller to provide an expectedDesc. */ if (!rsi || !IsA(rsi, ReturnSetInfo) || (rsi->allowedModes & SFRM_ValuePerCall) == 0 || (rsi->allowedModes & SFRM_Materialize) == 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("set-valued function called in context that cannot accept a set"))); randomAccess = rsi->allowedModes & SFRM_Materialize_Random; lazyEvalOK = !(rsi->allowedModes & SFRM_Materialize_Preferred); /* tuplestore, if used, must have query lifespan */ tscontext = rsi->econtext->ecxt_per_query_memory; } else { randomAccess = false; lazyEvalOK = true; /* we won't need a tuplestore */ tscontext = NULL; } /* * Initialize fcache if starting a fresh execution. */ fcache = init_sql_fcache(fcinfo, lazyEvalOK); /* Remember info that we might need later to construct tuplestore */ fcache->tscontext = tscontext; fcache->randomAccess = randomAccess; /* * Now we can set up error traceback support for ereport() */ sqlerrcontext.callback = sql_exec_error_callback; sqlerrcontext.arg = fcache; sqlerrcontext.previous = error_context_stack; error_context_stack = &sqlerrcontext; /* * Find first unfinished execution_state. If none, advance to the next * query in function. */ do { es = fcache->eslist; while (es && es->status == F_EXEC_DONE) es = es->next; if (es) break; } while (init_execution_state(fcache)); /* * Execute each command in the function one after another until we either * run out of commands or get a result row from a lazily-evaluated SELECT. * * Notes about snapshot management: * * In a read-only function, we just use the surrounding query's snapshot. * * In a non-read-only function, we rely on the fact that we'll never * suspend execution between queries of the function: the only reason to * suspend execution before completion is if we are returning a row from a * lazily-evaluated SELECT. So, when first entering this loop, we'll * either start a new query (and push a fresh snapshot) or re-establish * the active snapshot from the existing query descriptor. If we need to * start a new query in a subsequent execution of the loop, either we need * a fresh snapshot (and pushed_snapshot is false) or the existing * snapshot is on the active stack and we can just bump its command ID. */ pushed_snapshot = false; while (es) { bool completed; if (es->status == F_EXEC_START) { /* * If not read-only, be sure to advance the command counter for * each command, so that all work to date in this transaction is * visible. Take a new snapshot if we don't have one yet, * otherwise just bump the command ID in the existing snapshot. */ if (!fcache->func->readonly_func) { CommandCounterIncrement(); if (!pushed_snapshot) { PushActiveSnapshot(GetTransactionSnapshot()); pushed_snapshot = true; } else UpdateActiveSnapshotCommandId(); } postquel_start(es, fcache); } else if (!fcache->func->readonly_func && !pushed_snapshot) { /* Re-establish active snapshot when re-entering function */ PushActiveSnapshot(es->qd->snapshot); pushed_snapshot = true; } completed = postquel_getnext(es, fcache); /* * If we ran the command to completion, we can shut it down now. Any * row(s) we need to return are safely stashed in the result slot or * tuplestore, and we want to be sure that, for example, AFTER * triggers get fired before we return anything. Also, if the * function doesn't return set, we can shut it down anyway because it * must be a SELECT and we don't care about fetching any more result * rows. */ if (completed || !fcache->func->returnsSet) postquel_end(es, fcache); /* * Break from loop if we didn't shut down (implying we got a * lazily-evaluated row). Otherwise we'll press on till the whole * function is done, relying on the tuplestore to keep hold of the * data to eventually be returned. This is necessary since an * INSERT/UPDATE/DELETE RETURNING that sets the result might be * followed by additional rule-inserted commands, and we want to * finish doing all those commands before we return anything. */ if (es->status != F_EXEC_DONE) break; /* * Advance to next execution_state, and perhaps next query. */ es = es->next; while (!es) { /* * Flush the current snapshot so that we will take a new one for * the new query list. This ensures that new snaps are taken at * original-query boundaries, matching the behavior of interactive * execution. */ if (pushed_snapshot) { PopActiveSnapshot(); pushed_snapshot = false; } if (!init_execution_state(fcache)) break; /* end of function */ es = fcache->eslist; } } /* * The result slot or tuplestore now contains whatever row(s) we are * supposed to return. */ if (fcache->func->returnsSet) { ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo; if (es) { /* * If we stopped short of being done, we must have a lazy-eval * row. */ Assert(es->lazyEval); /* The junkfilter's result slot contains the query result tuple */ Assert(fcache->junkFilter); slot = fcache->junkFilter->jf_resultSlot; Assert(!TTS_EMPTY(slot)); /* Extract the result as a datum, and copy out from the slot */ result = postquel_get_single_result(slot, fcinfo, fcache); /* * Let caller know we're not finished. */ rsi->isDone = ExprMultipleResult; /* * Ensure we will get shut down cleanly if the exprcontext is not * run to completion. */ if (!fcache->shutdown_reg) { RegisterExprContextCallback(rsi->econtext, ShutdownSQLFunction, PointerGetDatum(fcache)); fcache->shutdown_reg = true; } } else if (fcache->lazyEval) { /* * We are done with a lazy evaluation. Let caller know we're * finished. */ rsi->isDone = ExprEndResult; fcinfo->isnull = true; result = (Datum) 0; /* Deregister shutdown callback, if we made one */ if (fcache->shutdown_reg) { UnregisterExprContextCallback(rsi->econtext, ShutdownSQLFunction, PointerGetDatum(fcache)); fcache->shutdown_reg = false; } } else { /* * We are done with a non-lazy evaluation. Return whatever is in * the tuplestore. (It is now caller's responsibility to free the * tuplestore when done.) * * Note an edge case: we could get here without having made a * tuplestore if the function is declared to return SETOF VOID. * ExecMakeTableFunctionResult will cope with null setResult. */ Assert(fcache->tstore || fcache->func->rettype == VOIDOID); rsi->returnMode = SFRM_Materialize; rsi->setResult = fcache->tstore; fcache->tstore = NULL; /* must copy desc because execSRF.c will free it */ if (fcache->junkFilter) rsi->setDesc = CreateTupleDescCopy(fcache->junkFilter->jf_cleanTupType); fcinfo->isnull = true; result = (Datum) 0; /* Deregister shutdown callback, if we made one */ if (fcache->shutdown_reg) { UnregisterExprContextCallback(rsi->econtext, ShutdownSQLFunction, PointerGetDatum(fcache)); fcache->shutdown_reg = false; } } } else { /* * Non-set function. If we got a row, return it; else return NULL. */ if (fcache->junkFilter) { /* The junkfilter's result slot contains the query result tuple */ slot = fcache->junkFilter->jf_resultSlot; if (!TTS_EMPTY(slot)) result = postquel_get_single_result(slot, fcinfo, fcache); else { fcinfo->isnull = true; result = (Datum) 0; } } else { /* Should only get here for VOID functions and procedures */ Assert(fcache->func->rettype == VOIDOID); fcinfo->isnull = true; result = (Datum) 0; } } /* Pop snapshot if we have pushed one */ if (pushed_snapshot) PopActiveSnapshot(); /* * If we've gone through every command in the function, we are done. Reset * state to start over again on next call. */ if (es == NULL) fcache->eslist = NULL; error_context_stack = sqlerrcontext.previous; return result; } /* * error context callback to let us supply a traceback during compile */ static void sql_compile_error_callback(void *arg) { SQLFunctionHashEntry *func = (SQLFunctionHashEntry *) arg; int syntaxerrposition; /* * We can do nothing useful if sql_compile_callback() didn't get as far as * copying the function name */ if (func->fname == NULL) return; /* * If there is a syntax error position, convert to internal syntax error */ syntaxerrposition = geterrposition(); if (syntaxerrposition > 0 && func->src != NULL) { errposition(0); internalerrposition(syntaxerrposition); internalerrquery(func->src); } /* * sql_compile_callback() doesn't do any per-query processing, so just * report the context as "during startup". */ errcontext("SQL function \"%s\" during startup", func->fname); } /* * error context callback to let us supply a call-stack traceback at runtime */ static void sql_exec_error_callback(void *arg) { SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) arg; int syntaxerrposition; /* * If there is a syntax error position, convert to internal syntax error */ syntaxerrposition = geterrposition(); if (syntaxerrposition > 0 && fcache->func->src != NULL) { errposition(0); internalerrposition(syntaxerrposition); internalerrquery(fcache->func->src); } /* * If we failed while executing an identifiable query within the function, * report that. Otherwise say it was "during startup". */ if (fcache->error_query_index > 0) errcontext("SQL function \"%s\" statement %d", fcache->func->fname, fcache->error_query_index); else errcontext("SQL function \"%s\" during startup", fcache->func->fname); } /* * ExprContext callback function * * We register this in the active ExprContext while a set-returning SQL * function is running, in case the function needs to be shut down before it * has been run to completion. Note that this will not be called during an * error abort, but we don't need it because transaction abort will take care * of releasing executor resources. */ static void ShutdownSQLFunction(Datum arg) { SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) DatumGetPointer(arg); execution_state *es; es = fcache->eslist; while (es) { /* Shut down anything still running */ if (es->status == F_EXEC_RUN) { /* Re-establish active snapshot for any called functions */ if (!fcache->func->readonly_func) PushActiveSnapshot(es->qd->snapshot); postquel_end(es, fcache); if (!fcache->func->readonly_func) PopActiveSnapshot(); } es = es->next; } fcache->eslist = NULL; /* Release tuplestore if we have one */ if (fcache->tstore) tuplestore_end(fcache->tstore); fcache->tstore = NULL; /* Release CachedPlan if we have one */ if (fcache->cplan) ReleaseCachedPlan(fcache->cplan, fcache->cowner); fcache->cplan = NULL; /* execUtils will deregister the callback... */ fcache->shutdown_reg = false; } /* * MemoryContext callback function * * We register this in the memory context that contains a SQLFunctionCache * struct. When the memory context is reset or deleted, we release the * reference count (if any) that the cache holds on the long-lived hash entry. * Note that this will happen even during error aborts. */ static void RemoveSQLFunctionCache(void *arg) { SQLFunctionCache *fcache = (SQLFunctionCache *) arg; /* Release reference count on SQLFunctionHashEntry */ if (fcache->func != NULL) { Assert(fcache->func->cfunc.use_count > 0); fcache->func->cfunc.use_count--; /* This should be unnecessary, but let's just be sure: */ fcache->func = NULL; } } /* * check_sql_fn_statements * * Check statements in an SQL function. Error out if there is anything that * is not acceptable. */ void check_sql_fn_statements(List *queryTreeLists) { ListCell *lc; /* We are given a list of sublists of Queries */ foreach(lc, queryTreeLists) { List *sublist = lfirst_node(List, lc); check_sql_fn_statement(sublist); } } /* * As above, for a single sublist of Queries. */ static void check_sql_fn_statement(List *queryTreeList) { ListCell *lc; foreach(lc, queryTreeList) { Query *query = lfirst_node(Query, lc); /* * Disallow calling procedures with output arguments. The current * implementation would just throw the output values away, unless the * statement is the last one. Per SQL standard, we should assign the * output values by name. By disallowing this here, we preserve an * opportunity for future improvement. */ if (query->commandType == CMD_UTILITY && IsA(query->utilityStmt, CallStmt)) { CallStmt *stmt = (CallStmt *) query->utilityStmt; if (stmt->outargs != NIL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("calling procedures with output arguments is not supported in SQL functions"))); } } } /* * check_sql_fn_retval() * Check return value of a list of lists of sql parse trees. * * The return value of a sql function is the value returned by the last * canSetTag query in the function. We do some ad-hoc type checking and * coercion here to ensure that the function returns what it's supposed to. * Note that we may actually modify the last query to make it match! * * This function returns true if the sql function returns the entire tuple * result of its final statement, or false if it returns just the first column * result of that statement. It throws an error if the final statement doesn't * return the right type at all. * * Note that because we allow "SELECT rowtype_expression", the result can be * false even when the declared function return type is a rowtype. * * For a polymorphic function the passed rettype must be the actual resolved * output type of the function. (This means we can't check the type during * function definition of a polymorphic function.) If we do see a polymorphic * rettype we'll throw an error, saying it is not a supported rettype. * * If the function returns composite, the passed rettupdesc should describe * the expected output. If rettupdesc is NULL, we can't verify that the * output matches; that should only happen in fmgr_sql_validator(), or when * the function returns RECORD and the caller doesn't actually care which * composite type it is. * * (Typically, rettype and rettupdesc are computed by get_call_result_type * or a sibling function.) * * In addition to coercing individual output columns, we can modify the * output to include dummy NULL columns for any dropped columns appearing * in rettupdesc. This is done only if the caller asks for it. */ bool check_sql_fn_retval(List *queryTreeLists, Oid rettype, TupleDesc rettupdesc, char prokind, bool insertDroppedCols) { List *queryTreeList; /* * We consider only the last sublist of Query nodes, so that only the last * original statement is a candidate to produce the result. This is a * change from pre-v18 versions, which would back up to the last statement * that includes a canSetTag query, thus ignoring any ending statement(s) * that rewrite to DO INSTEAD NOTHING. That behavior was undocumented and * there seems no good reason for it, except that it was an artifact of * the original coding. * * If the function body is completely empty, handle that the same as if * the last query had rewritten to nothing. */ if (queryTreeLists != NIL) queryTreeList = llast_node(List, queryTreeLists); else queryTreeList = NIL; return check_sql_stmt_retval(queryTreeList, rettype, rettupdesc, prokind, insertDroppedCols); } /* * As for check_sql_fn_retval, but we are given just the last query's * rewritten-queries list. */ static bool check_sql_stmt_retval(List *queryTreeList, Oid rettype, TupleDesc rettupdesc, char prokind, bool insertDroppedCols) { bool is_tuple_result = false; Query *parse; ListCell *parse_cell; List *tlist; int tlistlen; bool tlist_is_modifiable; char fn_typtype; List *upper_tlist = NIL; bool upper_tlist_nontrivial = false; ListCell *lc; /* * If it's declared to return VOID, we don't care what's in the function. * (This takes care of procedures with no output parameters, as well.) */ if (rettype == VOIDOID) return false; /* * Find the last canSetTag query in the list of Query nodes. This isn't * necessarily the last parsetree, because rule rewriting can insert * queries after what the user wrote. */ parse = NULL; parse_cell = NULL; foreach(lc, queryTreeList) { Query *q = lfirst_node(Query, lc); if (q->canSetTag) { parse = q; parse_cell = lc; } } /* * If it's a plain SELECT, it returns whatever the targetlist says. * Otherwise, if it's INSERT/UPDATE/DELETE/MERGE with RETURNING, it * returns that. Otherwise, the function return type must be VOID. * * Note: eventually replace this test with QueryReturnsTuples? We'd need * a more general method of determining the output type, though. Also, it * seems too dangerous to consider FETCH or EXECUTE as returning a * determinable rowtype, since they depend on relatively short-lived * entities. */ if (parse && parse->commandType == CMD_SELECT) { tlist = parse->targetList; /* tlist is modifiable unless it's a dummy in a setop query */ tlist_is_modifiable = (parse->setOperations == NULL); } else if (parse && (parse->commandType == CMD_INSERT || parse->commandType == CMD_UPDATE || parse->commandType == CMD_DELETE || parse->commandType == CMD_MERGE) && parse->returningList) { tlist = parse->returningList; /* returningList can always be modified */ tlist_is_modifiable = true; } else { /* Last statement is a utility command, or it rewrote to nothing */ ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type mismatch in function declared to return %s", format_type_be(rettype)), errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE/MERGE RETURNING."))); return false; /* keep compiler quiet */ } /* * OK, check that the targetlist returns something matching the declared * type, and modify it if necessary. If possible, we insert any coercion * steps right into the final statement's targetlist. However, that might * risk changes in the statement's semantics --- we can't safely change * the output type of a grouping column, for instance. In such cases we * handle coercions by inserting an extra level of Query that effectively * just does a projection. */ /* * Count the non-junk entries in the result targetlist. */ tlistlen = ExecCleanTargetListLength(tlist); fn_typtype = get_typtype(rettype); if (fn_typtype == TYPTYPE_BASE || fn_typtype == TYPTYPE_DOMAIN || fn_typtype == TYPTYPE_ENUM || fn_typtype == TYPTYPE_RANGE || fn_typtype == TYPTYPE_MULTIRANGE) { /* * For scalar-type returns, the target list must have exactly one * non-junk entry, and its type must be coercible to rettype. */ TargetEntry *tle; if (tlistlen != 1) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type mismatch in function declared to return %s", format_type_be(rettype)), errdetail("Final statement must return exactly one column."))); /* We assume here that non-junk TLEs must come first in tlists */ tle = (TargetEntry *) linitial(tlist); Assert(!tle->resjunk); if (!coerce_fn_result_column(tle, rettype, -1, tlist_is_modifiable, &upper_tlist, &upper_tlist_nontrivial)) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type mismatch in function declared to return %s", format_type_be(rettype)), errdetail("Actual return type is %s.", format_type_be(exprType((Node *) tle->expr))))); } else if (fn_typtype == TYPTYPE_COMPOSITE || rettype == RECORDOID) { /* * Returns a rowtype. * * Note that we will not consider a domain over composite to be a * "rowtype" return type; it goes through the scalar case above. This * is because we only provide column-by-column implicit casting, and * will not cast the complete record result. So the only way to * produce a domain-over-composite result is to compute it as an * explicit single-column result. The single-composite-column code * path just below could handle such cases, but it won't be reached. */ int tupnatts; /* physical number of columns in tuple */ int tuplogcols; /* # of nondeleted columns in tuple */ int colindex; /* physical column index */ /* * If the target list has one non-junk entry, and that expression has * or can be coerced to the declared return type, take it as the * result. This allows, for example, 'SELECT func2()', where func2 * has the same composite return type as the function that's calling * it. This provision creates some ambiguity --- maybe the expression * was meant to be the lone field of the composite result --- but it * works well enough as long as we don't get too enthusiastic about * inventing coercions from scalar to composite types. * * XXX Note that if rettype is RECORD and the expression is of a named * composite type, or vice versa, this coercion will succeed, whether * or not the record type really matches. For the moment we rely on * runtime type checking to catch any discrepancy, but it'd be nice to * do better at parse time. * * We must *not* do this for a procedure, however. Procedures with * output parameter(s) have rettype RECORD, and the CALL code expects * to get results corresponding to the list of output parameters, even * when there's just one parameter that's composite. */ if (tlistlen == 1 && prokind != PROKIND_PROCEDURE) { TargetEntry *tle = (TargetEntry *) linitial(tlist); Assert(!tle->resjunk); if (coerce_fn_result_column(tle, rettype, -1, tlist_is_modifiable, &upper_tlist, &upper_tlist_nontrivial)) { /* Note that we're NOT setting is_tuple_result */ goto tlist_coercion_finished; } } /* * If the caller didn't provide an expected tupdesc, we can't do any * further checking. Assume we're returning the whole tuple. */ if (rettupdesc == NULL) return true; /* * Verify that the targetlist matches the return tuple type. We scan * the non-resjunk columns, and coerce them if necessary to match the * datatypes of the non-deleted attributes. For deleted attributes, * insert NULL result columns if the caller asked for that. */ tupnatts = rettupdesc->natts; tuplogcols = 0; /* we'll count nondeleted cols as we go */ colindex = 0; foreach(lc, tlist) { TargetEntry *tle = (TargetEntry *) lfirst(lc); Form_pg_attribute attr; /* resjunk columns can simply be ignored */ if (tle->resjunk) continue; do { colindex++; if (colindex > tupnatts) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type mismatch in function declared to return %s", format_type_be(rettype)), errdetail("Final statement returns too many columns."))); attr = TupleDescAttr(rettupdesc, colindex - 1); if (attr->attisdropped && insertDroppedCols) { Expr *null_expr; /* The type of the null we insert isn't important */ null_expr = (Expr *) makeConst(INT4OID, -1, InvalidOid, sizeof(int32), (Datum) 0, true, /* isnull */ true /* byval */ ); upper_tlist = lappend(upper_tlist, makeTargetEntry(null_expr, list_length(upper_tlist) + 1, NULL, false)); upper_tlist_nontrivial = true; } } while (attr->attisdropped); tuplogcols++; if (!coerce_fn_result_column(tle, attr->atttypid, attr->atttypmod, tlist_is_modifiable, &upper_tlist, &upper_tlist_nontrivial)) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type mismatch in function declared to return %s", format_type_be(rettype)), errdetail("Final statement returns %s instead of %s at column %d.", format_type_be(exprType((Node *) tle->expr)), format_type_be(attr->atttypid), tuplogcols))); } /* remaining columns in rettupdesc had better all be dropped */ for (colindex++; colindex <= tupnatts; colindex++) { if (!TupleDescCompactAttr(rettupdesc, colindex - 1)->attisdropped) ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type mismatch in function declared to return %s", format_type_be(rettype)), errdetail("Final statement returns too few columns."))); if (insertDroppedCols) { Expr *null_expr; /* The type of the null we insert isn't important */ null_expr = (Expr *) makeConst(INT4OID, -1, InvalidOid, sizeof(int32), (Datum) 0, true, /* isnull */ true /* byval */ ); upper_tlist = lappend(upper_tlist, makeTargetEntry(null_expr, list_length(upper_tlist) + 1, NULL, false)); upper_tlist_nontrivial = true; } } /* Report that we are returning entire tuple result */ is_tuple_result = true; } else ereport(ERROR, (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION), errmsg("return type %s is not supported for SQL functions", format_type_be(rettype)))); tlist_coercion_finished: /* * If necessary, modify the final Query by injecting an extra Query level * that just performs a projection. (It'd be dubious to do this to a * non-SELECT query, but we never have to; RETURNING lists can always be * modified in-place.) */ if (upper_tlist_nontrivial) { Query *newquery; List *colnames; RangeTblEntry *rte; RangeTblRef *rtr; Assert(parse->commandType == CMD_SELECT); /* Most of the upper Query struct can be left as zeroes/nulls */ newquery = makeNode(Query); newquery->commandType = CMD_SELECT; newquery->querySource = parse->querySource; newquery->canSetTag = true; newquery->targetList = upper_tlist; /* We need a moderately realistic colnames list for the subquery RTE */ colnames = NIL; foreach(lc, parse->targetList) { TargetEntry *tle = (TargetEntry *) lfirst(lc); if (tle->resjunk) continue; colnames = lappend(colnames, makeString(tle->resname ? tle->resname : "")); } /* Build a suitable RTE for the subquery */ rte = makeNode(RangeTblEntry); rte->rtekind = RTE_SUBQUERY; rte->subquery = parse; rte->eref = rte->alias = makeAlias("*SELECT*", colnames); rte->lateral = false; rte->inh = false; rte->inFromCl = true; newquery->rtable = list_make1(rte); rtr = makeNode(RangeTblRef); rtr->rtindex = 1; newquery->jointree = makeFromExpr(list_make1(rtr), NULL); /* * Make sure the new query is marked as having row security if the * original one does. */ newquery->hasRowSecurity = parse->hasRowSecurity; /* Replace original query in the correct element of the query list */ lfirst(parse_cell) = newquery; } return is_tuple_result; } /* * Process one function result column for check_sql_fn_retval * * Coerce the output value to the required type/typmod, and add a column * to *upper_tlist for it. Set *upper_tlist_nontrivial to true if we * add an upper tlist item that's not just a Var. * * Returns true if OK, false if could not coerce to required type * (in which case, no changes have been made) */ static bool coerce_fn_result_column(TargetEntry *src_tle, Oid res_type, int32 res_typmod, bool tlist_is_modifiable, List **upper_tlist, bool *upper_tlist_nontrivial) { TargetEntry *new_tle; Expr *new_tle_expr; Node *cast_result; /* * If the TLE has a sortgroupref marking, don't change it, as it probably * is referenced by ORDER BY, DISTINCT, etc, and changing its type would * break query semantics. Otherwise, it's safe to modify in-place unless * the query as a whole has issues with that. */ if (tlist_is_modifiable && src_tle->ressortgroupref == 0) { /* OK to modify src_tle in place, if necessary */ cast_result = coerce_to_target_type(NULL, (Node *) src_tle->expr, exprType((Node *) src_tle->expr), res_type, res_typmod, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST, -1); if (cast_result == NULL) return false; assign_expr_collations(NULL, cast_result); src_tle->expr = (Expr *) cast_result; /* Make a Var referencing the possibly-modified TLE */ new_tle_expr = (Expr *) makeVarFromTargetEntry(1, src_tle); } else { /* Any casting must happen in the upper tlist */ Var *var = makeVarFromTargetEntry(1, src_tle); cast_result = coerce_to_target_type(NULL, (Node *) var, var->vartype, res_type, res_typmod, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST, -1); if (cast_result == NULL) return false; assign_expr_collations(NULL, cast_result); /* Did the coercion actually do anything? */ if (cast_result != (Node *) var) *upper_tlist_nontrivial = true; new_tle_expr = (Expr *) cast_result; } new_tle = makeTargetEntry(new_tle_expr, list_length(*upper_tlist) + 1, src_tle->resname, false); *upper_tlist = lappend(*upper_tlist, new_tle); return true; } /* * Extract the targetlist of the last canSetTag query in the given list * of parsed-and-rewritten Queries. Returns NIL if there is none. */ static List * get_sql_fn_result_tlist(List *queryTreeList) { Query *parse = NULL; ListCell *lc; foreach(lc, queryTreeList) { Query *q = lfirst_node(Query, lc); if (q->canSetTag) parse = q; } if (parse && parse->commandType == CMD_SELECT) return parse->targetList; else if (parse && (parse->commandType == CMD_INSERT || parse->commandType == CMD_UPDATE || parse->commandType == CMD_DELETE || parse->commandType == CMD_MERGE) && parse->returningList) return parse->returningList; else return NIL; } /* * CreateSQLFunctionDestReceiver -- create a suitable DestReceiver object */ DestReceiver * CreateSQLFunctionDestReceiver(void) { DR_sqlfunction *self = (DR_sqlfunction *) palloc0(sizeof(DR_sqlfunction)); self->pub.receiveSlot = sqlfunction_receive; self->pub.rStartup = sqlfunction_startup; self->pub.rShutdown = sqlfunction_shutdown; self->pub.rDestroy = sqlfunction_destroy; self->pub.mydest = DestSQLFunction; /* private fields will be set by postquel_start */ return (DestReceiver *) self; } /* * sqlfunction_startup --- executor startup */ static void sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo) { /* no-op */ } /* * sqlfunction_receive --- receive one tuple */ static bool sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self) { DR_sqlfunction *myState = (DR_sqlfunction *) self; if (myState->tstore) { /* We are collecting all of a set result into the tuplestore */ /* Filter tuple as needed */ slot = ExecFilterJunk(myState->filter, slot); /* Store the filtered tuple into the tuplestore */ tuplestore_puttupleslot(myState->tstore, slot); } else { /* * We only want the first tuple, which we'll save in the junkfilter's * result slot. Ignore any additional tuples passed. */ if (TTS_EMPTY(myState->filter->jf_resultSlot)) { /* Filter tuple as needed */ slot = ExecFilterJunk(myState->filter, slot); Assert(slot == myState->filter->jf_resultSlot); /* Materialize the slot so it preserves pass-by-ref values */ ExecMaterializeSlot(slot); } } return true; } /* * sqlfunction_shutdown --- executor end */ static void sqlfunction_shutdown(DestReceiver *self) { /* no-op */ } /* * sqlfunction_destroy --- release DestReceiver object */ static void sqlfunction_destroy(DestReceiver *self) { pfree(self); }