/*------------------------------------------------------------------------- * * functions.c * Execution of SQL-language functions * * Portions Copyright (c) 1996-2021, 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/lsyscache.h" #include "utils/memutils.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 */ MemoryContext cxt; /* context containing tstore */ JunkFilter *filter; /* filter to convert tuple type */ } DR_sqlfunction; /* * We have an execution_state record for each query in a function. Each * record contains 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.) */ 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; /* * An SQLFunctionCache record is built during the first call, * and linked to from the fn_extra field of the FmgrInfo struct. * * Note that currently this has only the lifespan of the calling query. * Someday we should rewrite this code to use plancache.c to save parse/plan * results for longer than that. * * Physically, though, the data has the lifespan of the FmgrInfo that's used * to call the function, and there are cases (particularly with indexes) * where the FmgrInfo might survive across transactions. We cannot assume * that the parse/plan trees are good for longer than the (sub)transaction in * which parsing was done, so we must mark the record with the LXID/subxid of * its creation time, and regenerate everything if that's obsolete. To avoid * memory leakage when we do have to regenerate things, all the data is kept * in a sub-context of the FmgrInfo's fn_mcxt. */ typedef struct { char *fname; /* function name (for error msgs) */ char *src; /* function body text (for error msgs) */ SQLFunctionParseInfoPtr pinfo; /* data for parser callback hooks */ 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 shutdown_reg; /* true if registered shutdown callback */ bool readonly_func; /* true to run in "read only" mode */ bool lazyEval; /* true if using lazyEval for result query */ ParamListInfo paramLI; /* Param list representing current args */ Tuplestorestate *tstore; /* where we accumulate result tuples */ JunkFilter *junkFilter; /* will be NULL if function returns VOID */ /* * func_state is a List of execution_state records, each of which is the * first for its original parsetree, with any additional records chained * to it via the "next" fields. This sublist structure is needed to keep * track of where the original query boundaries are. */ List *func_state; MemoryContext fcontext; /* memory context holding this struct and all * subsidiary data */ LocalTransactionId lxid; /* lxid in which cache was made */ SubTransactionId subxid; /* subxid in which cache was made */ } 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 List *init_execution_state(List *queryTree_list, SQLFunctionCachePtr fcache, bool lazyEvalOK); static void init_sql_fcache(FunctionCallInfo fcinfo, Oid collation, bool lazyEvalOK); 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); static void postquel_sub_params(SQLFunctionCachePtr fcache, FunctionCallInfo fcinfo); static Datum postquel_get_single_result(TupleTableSlot *slot, FunctionCallInfo fcinfo, SQLFunctionCachePtr fcache, MemoryContext resultcontext); static void sql_exec_error_callback(void *arg); static void ShutdownSQLFunction(Datum arg); 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 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 = (void *) 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); Assert(IsA(field1, String)); name1 = strVal(field1); if (nnames > 1) { subfield = (Node *) lsecond(cref->fields); Assert(IsA(subfield, String)); 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; } /* * Set up the per-query execution_state records for a SQL function. * * The input is a List of Lists of parsed and rewritten, but not planned, * querytrees. The sublist structure denotes the original query boundaries. */ static List * init_execution_state(List *queryTree_list, SQLFunctionCachePtr fcache, bool lazyEvalOK) { List *eslist = NIL; execution_state *lasttages = NULL; ListCell *lc1; foreach(lc1, queryTree_list) { List *qtlist = lfirst_node(List, lc1); execution_state *firstes = NULL; execution_state *preves = NULL; ListCell *lc2; foreach(lc2, qtlist) { Query *queryTree = lfirst_node(Query, lc2); PlannedStmt *stmt; execution_state *newes; /* Plan the query if needed */ if (queryTree->commandType == CMD_UTILITY) { /* Utility commands require no planning. */ stmt = makeNode(PlannedStmt); stmt->commandType = CMD_UTILITY; stmt->canSetTag = queryTree->canSetTag; stmt->utilityStmt = queryTree->utilityStmt; stmt->stmt_location = queryTree->stmt_location; stmt->stmt_len = queryTree->stmt_len; } else stmt = pg_plan_query(queryTree, fcache->src, CURSOR_OPT_PARALLEL_OK, NULL); /* * 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->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 = (execution_state *) palloc(sizeof(execution_state)); if (preves) preves->next = newes; else firstes = 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 (queryTree->canSetTag) lasttages = newes; preves = newes; } eslist = lappend(eslist, firstes); } /* * 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 (lazyEvalOK && lasttages->stmt->commandType == CMD_SELECT && !lasttages->stmt->hasModifyingCTE) fcache->lazyEval = lasttages->lazyEval = true; } return eslist; } /* * Initialize the SQLFunctionCache for a SQL function */ static void init_sql_fcache(FunctionCallInfo fcinfo, Oid collation, bool lazyEvalOK) { FmgrInfo *finfo = fcinfo->flinfo; Oid foid = finfo->fn_oid; MemoryContext fcontext; MemoryContext oldcontext; Oid rettype; TupleDesc rettupdesc; HeapTuple procedureTuple; Form_pg_proc procedureStruct; SQLFunctionCachePtr fcache; List *queryTree_list; List *resulttlist; ListCell *lc; Datum tmp; bool isNull; /* * Create memory context that holds all the SQLFunctionCache data. It * must be a child of whatever context holds the FmgrInfo. */ fcontext = AllocSetContextCreate(finfo->fn_mcxt, "SQL function", ALLOCSET_DEFAULT_SIZES); oldcontext = MemoryContextSwitchTo(fcontext); /* * Create the struct proper, link it to fcontext and fn_extra. Once this * is done, we'll be able to recover the memory after failure, even if the * FmgrInfo is long-lived. */ fcache = (SQLFunctionCachePtr) palloc0(sizeof(SQLFunctionCache)); fcache->fcontext = fcontext; finfo->fn_extra = (void *) fcache; /* * get the procedure tuple corresponding to the given function Oid */ procedureTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(foid)); if (!HeapTupleIsValid(procedureTuple)) elog(ERROR, "cache lookup failed for function %u", foid); procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple); /* * copy function name immediately for use by error reporting callback, and * for use as memory context identifier */ fcache->fname = pstrdup(NameStr(procedureStruct->proname)); MemoryContextSetIdentifier(fcontext, fcache->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); fcache->rettype = rettype; /* Fetch the typlen and byval info for the result type */ get_typlenbyval(rettype, &fcache->typlen, &fcache->typbyval); /* Remember whether we're returning setof something */ fcache->returnsSet = procedureStruct->proretset; /* Remember if function is STABLE/IMMUTABLE */ fcache->readonly_func = (procedureStruct->provolatile != PROVOLATILE_VOLATILE); /* * 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. */ fcache->pinfo = prepare_sql_fn_parse_info(procedureTuple, finfo->fn_expr, collation); /* * And of course we need the function body text. */ tmp = SysCacheGetAttr(PROCOID, procedureTuple, Anum_pg_proc_prosrc, &isNull); if (isNull) elog(ERROR, "null prosrc for function %u", foid); fcache->src = TextDatumGetCString(tmp); /* If we have prosqlbody, pay attention to that not prosrc. */ tmp = SysCacheGetAttr(PROCOID, procedureTuple, Anum_pg_proc_prosqlbody, &isNull); /* * Parse and rewrite the queries in the function text. Use sublists to * keep track of the original query boundaries. * * Note: since parsing and planning is done in fcontext, we will generate * a lot of cruft that lives as long as the fcache does. This is annoying * but we'll not worry about it until the module is rewritten to use * plancache.c. */ queryTree_list = NIL; if (!isNull) { Node *n; List *stored_query_list; n = stringToNode(TextDatumGetCString(tmp)); if (IsA(n, List)) stored_query_list = linitial_node(List, castNode(List, n)); else stored_query_list = list_make1(n); foreach(lc, stored_query_list) { Query *parsetree = lfirst_node(Query, lc); List *queryTree_sublist; AcquireRewriteLocks(parsetree, true, false); queryTree_sublist = pg_rewrite_query(parsetree); queryTree_list = lappend(queryTree_list, queryTree_sublist); } } else { List *raw_parsetree_list; raw_parsetree_list = pg_parse_query(fcache->src); foreach(lc, raw_parsetree_list) { RawStmt *parsetree = lfirst_node(RawStmt, lc); List *queryTree_sublist; queryTree_sublist = pg_analyze_and_rewrite_params(parsetree, fcache->src, (ParserSetupHook) sql_fn_parser_setup, fcache->pinfo, NULL); queryTree_list = lappend(queryTree_list, queryTree_sublist); } } /* * Check that there are no statements we don't want to allow. */ check_sql_fn_statements(queryTree_list); /* * 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_fn_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 fcache->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.) */ fcache->returnsTuple = check_sql_fn_retval(queryTree_list, rettype, rettupdesc, false, &resulttlist); /* * 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.) */ if (rettype != VOIDOID) { TupleTableSlot *slot = MakeSingleTupleTableSlot(NULL, &TTSOpsMinimalTuple); /* * 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 (rettupdesc && fcache->returnsTuple) fcache->junkFilter = ExecInitJunkFilterConversion(resulttlist, rettupdesc, slot); else fcache->junkFilter = ExecInitJunkFilter(resulttlist, slot); } if (fcache->returnsTuple) { /* Make sure output rowtype is properly blessed */ BlessTupleDesc(fcache->junkFilter->jf_resultSlot->tts_tupleDescriptor); } else if (fcache->returnsSet && type_is_rowtype(fcache->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 to add more smarts in init_execution_state * about this, we'd probably need a three-way flag instead of bool. */ lazyEvalOK = true; } /* Finally, plan the queries */ fcache->func_state = init_execution_state(queryTree_list, fcache, lazyEvalOK); /* Mark fcache with time of creation to show it's valid */ fcache->lxid = MyProc->lxid; fcache->subxid = GetCurrentSubTransactionId(); ReleaseSysCache(procedureTuple); MemoryContextSwitchTo(oldcontext); } /* Start up execution of one execution_state node */ static void postquel_start(execution_state *es, SQLFunctionCachePtr fcache) { DestReceiver *dest; Assert(es->qd == NULL); /* Caller should have ensured a suitable snapshot is active */ Assert(ActiveSnapshotSet()); /* * If this query produces the function result, send its output to the * tuplestore; 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; myState->cxt = CurrentMemoryContext; myState->filter = fcache->junkFilter; } else dest = None_Receiver; es->qd = CreateQueryDesc(es->stmt, fcache->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; } /* 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; if (es->qd->operation == CMD_UTILITY) { ProcessUtility(es->qd->plannedstmt, fcache->src, false, 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, !fcache->returnsSet || !es->lazyEval); /* * 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); } return result; } /* Shut down execution of one execution_state node */ static void postquel_end(execution_state *es) { /* 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; } /* Build ParamListInfo array representing current arguments */ static void postquel_sub_params(SQLFunctionCachePtr fcache, FunctionCallInfo fcinfo) { int nargs = fcinfo->nargs; if (nargs > 0) { ParamListInfo paramLI; if (fcache->paramLI == NULL) { paramLI = makeParamList(nargs); fcache->paramLI = paramLI; } else { paramLI = fcache->paramLI; Assert(paramLI->numParams == nargs); } for (int i = 0; i < nargs; i++) { ParamExternData *prm = ¶mLI->params[i]; prm->value = fcinfo->args[i].value; prm->isnull = fcinfo->args[i].isnull; prm->pflags = 0; prm->ptype = fcache->pinfo->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. */ static Datum postquel_get_single_result(TupleTableSlot *slot, FunctionCallInfo fcinfo, SQLFunctionCachePtr fcache, MemoryContext resultcontext) { Datum value; MemoryContext oldcontext; /* * Set up to return the function value. For pass-by-reference datatypes, * be sure to allocate the result in resultcontext, not the current memory * context (which has query lifespan). We can't leave the data in the * TupleTableSlot because we intend to clear the slot before returning. */ oldcontext = MemoryContextSwitchTo(resultcontext); if (fcache->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 result context if needed. */ value = slot_getattr(slot, 1, &(fcinfo->isnull)); if (!fcinfo->isnull) value = datumCopy(value, fcache->typbyval, fcache->typlen); } MemoryContextSwitchTo(oldcontext); return value; } /* * fmgr_sql: function call manager for SQL functions */ Datum fmgr_sql(PG_FUNCTION_ARGS) { SQLFunctionCachePtr fcache; ErrorContextCallback sqlerrcontext; MemoryContext oldcontext; bool randomAccess; bool lazyEvalOK; bool is_first; bool pushed_snapshot; execution_state *es; TupleTableSlot *slot; Datum result; List *eslist; ListCell *eslc; /* * Setup error traceback support for ereport() */ sqlerrcontext.callback = sql_exec_error_callback; sqlerrcontext.arg = fcinfo->flinfo; sqlerrcontext.previous = error_context_stack; error_context_stack = &sqlerrcontext; /* 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); } else { randomAccess = false; lazyEvalOK = true; } /* * Initialize fcache (build plans) if first time through; or re-initialize * if the cache is stale. */ fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra; if (fcache != NULL) { if (fcache->lxid != MyProc->lxid || !SubTransactionIsActive(fcache->subxid)) { /* It's stale; unlink and delete */ fcinfo->flinfo->fn_extra = NULL; MemoryContextDelete(fcache->fcontext); fcache = NULL; } } if (fcache == NULL) { init_sql_fcache(fcinfo, PG_GET_COLLATION(), lazyEvalOK); fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra; } /* * Switch to context in which the fcache lives. This ensures that our * tuplestore etc will have sufficient lifetime. The sub-executor is * responsible for deleting per-tuple information. (XXX in the case of a * long-lived FmgrInfo, this policy represents more memory leakage, but * it's not entirely clear where to keep stuff instead.) */ oldcontext = MemoryContextSwitchTo(fcache->fcontext); /* * Find first unfinished query in function, and note whether it's the * first query. */ eslist = fcache->func_state; es = NULL; is_first = true; foreach(eslc, eslist) { es = (execution_state *) lfirst(eslc); while (es && es->status == F_EXEC_DONE) { is_first = false; es = es->next; } if (es) break; } /* * Convert params to appropriate format if starting a fresh execution. (If * continuing execution, we can re-use prior params.) */ if (is_first && es && es->status == F_EXEC_START) postquel_sub_params(fcache, fcinfo); /* * Build tuplestore to hold results, if we don't have one already. Note * it's in the query-lifespan context. */ if (!fcache->tstore) fcache->tstore = tuplestore_begin_heap(randomAccess, false, work_mem); /* * 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->readonly_func) { CommandCounterIncrement(); if (!pushed_snapshot) { PushActiveSnapshot(GetTransactionSnapshot()); pushed_snapshot = true; } else UpdateActiveSnapshotCommandId(); } postquel_start(es, fcache); } else if (!fcache->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 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->returnsSet) postquel_end(es); /* * 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, which might be in the next list. */ es = es->next; while (!es) { eslc = lnext(eslist, eslc); if (!eslc) break; /* end of function */ es = (execution_state *) lfirst(eslc); /* * 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; } } } /* * The tuplestore now contains whatever row(s) we are supposed to return. */ if (fcache->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); /* Re-use the junkfilter's output slot to fetch back the tuple */ Assert(fcache->junkFilter); slot = fcache->junkFilter->jf_resultSlot; if (!tuplestore_gettupleslot(fcache->tstore, true, false, slot)) elog(ERROR, "failed to fetch lazy-eval tuple"); /* Extract the result as a datum, and copy out from the slot */ result = postquel_get_single_result(slot, fcinfo, fcache, oldcontext); /* Clear the tuplestore, but keep it for next time */ /* NB: this might delete the slot's content, but we don't care */ tuplestore_clear(fcache->tstore); /* * 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. Clean up. */ tuplestore_clear(fcache->tstore); /* * 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.) */ 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) { /* Re-use the junkfilter's output slot to fetch back the tuple */ slot = fcache->junkFilter->jf_resultSlot; if (tuplestore_gettupleslot(fcache->tstore, true, false, slot)) result = postquel_get_single_result(slot, fcinfo, fcache, oldcontext); else { fcinfo->isnull = true; result = (Datum) 0; } } else { /* Should only get here for VOID functions and procedures */ Assert(fcache->rettype == VOIDOID); fcinfo->isnull = true; result = (Datum) 0; } /* Clear the tuplestore, but keep it for next time */ tuplestore_clear(fcache->tstore); } /* 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 * the execution states to start over again on next call. */ if (es == NULL) { foreach(eslc, fcache->func_state) { es = (execution_state *) lfirst(eslc); while (es) { es->status = F_EXEC_START; es = es->next; } } } error_context_stack = sqlerrcontext.previous; MemoryContextSwitchTo(oldcontext); return result; } /* * error context callback to let us supply a call-stack traceback */ static void sql_exec_error_callback(void *arg) { FmgrInfo *flinfo = (FmgrInfo *) arg; SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) flinfo->fn_extra; int syntaxerrposition; /* * We can do nothing useful if init_sql_fcache() didn't get as far as * saving the function name */ if (fcache == NULL || fcache->fname == NULL) return; /* * If there is a syntax error position, convert to internal syntax error */ syntaxerrposition = geterrposition(); if (syntaxerrposition > 0 && fcache->src != NULL) { errposition(0); internalerrposition(syntaxerrposition); internalerrquery(fcache->src); } /* * Try to determine where in the function we failed. If there is a query * with non-null QueryDesc, finger it. (We check this rather than looking * for F_EXEC_RUN state, so that errors during ExecutorStart or * ExecutorEnd are blamed on the appropriate query; see postquel_start and * postquel_end.) */ if (fcache->func_state) { execution_state *es; int query_num; ListCell *lc; es = NULL; query_num = 1; foreach(lc, fcache->func_state) { es = (execution_state *) lfirst(lc); while (es) { if (es->qd) { errcontext("SQL function \"%s\" statement %d", fcache->fname, query_num); break; } es = es->next; } if (es) break; query_num++; } if (es == NULL) { /* * couldn't identify a running query; might be function entry, * function exit, or between queries. */ errcontext("SQL function \"%s\"", fcache->fname); } } else { /* * Assume we failed during init_sql_fcache(). (It's possible that the * function actually has an empty body, but in that case we may as * well report all errors as being "during startup".) */ errcontext("SQL function \"%s\" during startup", fcache->fname); } } /* * callback function in case a function-returning-set needs to be shut down * before it has been run to completion */ static void ShutdownSQLFunction(Datum arg) { SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) DatumGetPointer(arg); execution_state *es; ListCell *lc; foreach(lc, fcache->func_state) { es = (execution_state *) lfirst(lc); while (es) { /* Shut down anything still running */ if (es->status == F_EXEC_RUN) { /* Re-establish active snapshot for any called functions */ if (!fcache->readonly_func) PushActiveSnapshot(es->qd->snapshot); postquel_end(es); if (!fcache->readonly_func) PopActiveSnapshot(); } /* Reset states to START in case we're called again */ es->status = F_EXEC_START; es = es->next; } } /* Release tuplestore if we have one */ if (fcache->tstore) tuplestore_end(fcache->tstore); fcache->tstore = NULL; /* execUtils will deregister the callback... */ fcache->shutdown_reg = false; } /* * 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); ListCell *lc2; foreach(lc2, sublist) { Query *query = lfirst_node(Query, lc2); /* * 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. * * If resultTargetList isn't NULL, then *resultTargetList is set to the * targetlist that defines the final statement's result. Exception: if the * function is defined to return VOID then *resultTargetList is set to NIL. */ bool check_sql_fn_retval(List *queryTreeLists, Oid rettype, TupleDesc rettupdesc, bool insertDroppedCols, List **resultTargetList) { 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 (resultTargetList) *resultTargetList = NIL; /* initialize in case of VOID result */ /* * If it's declared to return VOID, we don't care what's in the function. * (This takes care of the procedure case, as well.) */ if (rettype == VOIDOID) return false; /* * Find the last canSetTag query in the function body (which is presented * to us as a list of sublists of Query nodes). This isn't necessarily * the last parsetree, because rule rewriting can insert queries after * what the user wrote. Note that it might not even be in the last * sublist, for example if the last query rewrites to DO INSTEAD NOTHING. * (It might not be unreasonable to throw an error in such a case, but * this is the historical behavior and it doesn't seem worth changing.) */ parse = NULL; parse_cell = NULL; foreach(lc, queryTreeLists) { List *sublist = lfirst_node(List, lc); ListCell *lc2; foreach(lc2, sublist) { Query *q = lfirst_node(Query, lc2); if (q->canSetTag) { parse = q; parse_cell = lc2; } } } /* * If it's a plain SELECT, it returns whatever the targetlist says. * Otherwise, if it's INSERT/UPDATE/DELETE 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->returningList) { tlist = parse->returningList; /* returningList can always be modified */ tlist_is_modifiable = true; } else { /* Empty function body, or last statement is a utility command */ 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 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. */ if (tlistlen == 1) { 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 tlist if requested */ if (resultTargetList) *resultTargetList = tlist; 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 (!TupleDescAttr(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); /* Replace original query in the correct element of the query list */ lfirst(parse_cell) = newquery; } /* Return tlist (possibly modified) if requested */ if (resultTargetList) *resultTargetList = upper_tlist; 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; } /* * 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; /* Filter tuple as needed */ slot = ExecFilterJunk(myState->filter, slot); /* Store the filtered tuple into the tuplestore */ tuplestore_puttupleslot(myState->tstore, 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); }