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/*-------------------------------------------------------------------------
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* Execution of SQL-language functions
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* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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* src/backend/executor/functions.c
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*-------------------------------------------------------------------------
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#include "access/xact.h"
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#include "catalog/pg_proc.h"
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#include "catalog/pg_type.h"
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#include "commands/trigger.h"
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#include "executor/functions.h"
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#include "miscadmin.h"
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#include "nodes/makefuncs.h"
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#include "nodes/nodeFuncs.h"
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#include "parser/parse_coerce.h"
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#include "tcop/utility.h"
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#include "utils/builtins.h"
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#include "utils/datum.h"
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#include "utils/lsyscache.h"
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#include "utils/snapmgr.h"
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#include "utils/syscache.h"
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* Specialized DestReceiver for collecting query output in a SQL function
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DestReceiver pub; /* publicly-known function pointers */
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Tuplestorestate *tstore; /* where to put result tuples */
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MemoryContext cxt; /* context containing tstore */
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JunkFilter *filter; /* filter to convert tuple type */
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* We have an execution_state record for each query in a function. Each
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* record contains a plantree for its query. If the query is currently in
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* F_EXEC_RUN state then there's a QueryDesc too.
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* The "next" fields chain together all the execution_state records generated
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* from a single original parsetree. (There will only be more than one in
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* case of rule expansion of the original parsetree.)
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F_EXEC_START, F_EXEC_RUN, F_EXEC_DONE
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typedef struct execution_state
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struct execution_state *next;
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bool setsResult; /* true if this query produces func's result */
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bool lazyEval; /* true if should fetch one row at a time */
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Node *stmt; /* PlannedStmt or utility statement */
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QueryDesc *qd; /* null unless status == RUN */
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* An SQLFunctionCache record is built during the first call,
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* and linked to from the fn_extra field of the FmgrInfo struct.
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* Note that currently this has only the lifespan of the calling query.
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* Someday we might want to consider caching the parse/plan results longer
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char *fname; /* function name (for error msgs) */
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char *src; /* function body text (for error msgs) */
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SQLFunctionParseInfoPtr pinfo; /* data for parser callback hooks */
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Oid rettype; /* actual return type */
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int16 typlen; /* length of the return type */
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bool typbyval; /* true if return type is pass by value */
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bool returnsSet; /* true if returning multiple rows */
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bool returnsTuple; /* true if returning whole tuple result */
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bool shutdown_reg; /* true if registered shutdown callback */
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bool readonly_func; /* true to run in "read only" mode */
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bool lazyEval; /* true if using lazyEval for result query */
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ParamListInfo paramLI; /* Param list representing current args */
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Tuplestorestate *tstore; /* where we accumulate result tuples */
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JunkFilter *junkFilter; /* will be NULL if function returns VOID */
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* func_state is a List of execution_state records, each of which is the
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* first for its original parsetree, with any additional records chained
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* to it via the "next" fields. This sublist structure is needed to keep
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* track of where the original query boundaries are.
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typedef SQLFunctionCache *SQLFunctionCachePtr;
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* Data structure needed by the parser callback hooks to resolve parameter
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* references during parsing of a SQL function's body. This is separate from
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* SQLFunctionCache since we sometimes do parsing separately from execution.
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typedef struct SQLFunctionParseInfo
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Oid *argtypes; /* resolved types of input arguments */
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int nargs; /* number of input arguments */
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Oid collation; /* function's input collation, if known */
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} SQLFunctionParseInfo;
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/* non-export function prototypes */
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static Node *sql_fn_param_ref(ParseState *pstate, ParamRef *pref);
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static List *init_execution_state(List *queryTree_list,
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SQLFunctionCachePtr fcache,
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static void init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK);
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static void postquel_start(execution_state *es, SQLFunctionCachePtr fcache);
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static bool postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache);
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static void postquel_end(execution_state *es);
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static void postquel_sub_params(SQLFunctionCachePtr fcache,
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FunctionCallInfo fcinfo);
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static Datum postquel_get_single_result(TupleTableSlot *slot,
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FunctionCallInfo fcinfo,
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SQLFunctionCachePtr fcache,
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MemoryContext resultcontext);
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static void sql_exec_error_callback(void *arg);
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static void ShutdownSQLFunction(Datum arg);
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static void sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo);
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static void sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self);
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static void sqlfunction_shutdown(DestReceiver *self);
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static void sqlfunction_destroy(DestReceiver *self);
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* Prepare the SQLFunctionParseInfo struct for parsing a SQL function body
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* This includes resolving actual types of polymorphic arguments.
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* call_expr can be passed as NULL, but then we will fail if there are any
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* polymorphic arguments.
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SQLFunctionParseInfoPtr
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prepare_sql_fn_parse_info(HeapTuple procedureTuple,
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SQLFunctionParseInfoPtr pinfo;
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Form_pg_proc procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
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pinfo = (SQLFunctionParseInfoPtr) palloc0(sizeof(SQLFunctionParseInfo));
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/* Save the function's input collation */
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pinfo->collation = inputCollation;
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* Copy input argument types from the pg_proc entry, then resolve any
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pinfo->nargs = nargs = procedureStruct->pronargs;
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argOidVect = (Oid *) palloc(nargs * sizeof(Oid));
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procedureStruct->proargtypes.values,
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nargs * sizeof(Oid));
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for (argnum = 0; argnum < nargs; argnum++)
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Oid argtype = argOidVect[argnum];
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if (IsPolymorphicType(argtype))
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argtype = get_call_expr_argtype(call_expr, argnum);
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if (argtype == InvalidOid)
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(errcode(ERRCODE_DATATYPE_MISMATCH),
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errmsg("could not determine actual type of argument declared %s",
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format_type_be(argOidVect[argnum]))));
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argOidVect[argnum] = argtype;
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pinfo->argtypes = argOidVect;
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* Parser setup hook for parsing a SQL function body.
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sql_fn_parser_setup(struct ParseState *pstate, SQLFunctionParseInfoPtr pinfo)
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/* Later we might use these hooks to support parameter names */
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pstate->p_pre_columnref_hook = NULL;
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pstate->p_post_columnref_hook = NULL;
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pstate->p_paramref_hook = sql_fn_param_ref;
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/* no need to use p_coerce_param_hook */
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pstate->p_ref_hook_state = (void *) pinfo;
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* sql_fn_param_ref parser callback for ParamRefs ($n symbols)
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sql_fn_param_ref(ParseState *pstate, ParamRef *pref)
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SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state;
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int paramno = pref->number;
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/* Check parameter number is valid */
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if (paramno <= 0 || paramno > pinfo->nargs)
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return NULL; /* unknown parameter number */
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param = makeNode(Param);
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param->paramkind = PARAM_EXTERN;
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param->paramid = paramno;
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param->paramtype = pinfo->argtypes[paramno - 1];
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param->paramtypmod = -1;
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param->paramcollid = get_typcollation(param->paramtype);
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param->location = pref->location;
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* If we have a function input collation, allow it to override the
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* type-derived collation for parameter symbols. (XXX perhaps this should
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* not happen if the type collation is not default?)
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if (OidIsValid(pinfo->collation) && OidIsValid(param->paramcollid))
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param->paramcollid = pinfo->collation;
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return (Node *) param;
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* Set up the per-query execution_state records for a SQL function.
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* The input is a List of Lists of parsed and rewritten, but not planned,
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* querytrees. The sublist structure denotes the original query boundaries.
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init_execution_state(List *queryTree_list,
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SQLFunctionCachePtr fcache,
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execution_state *lasttages = NULL;
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foreach(lc1, queryTree_list)
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List *qtlist = (List *) lfirst(lc1);
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execution_state *firstes = NULL;
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execution_state *preves = NULL;
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Query *queryTree = (Query *) lfirst(lc2);
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execution_state *newes;
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Assert(IsA(queryTree, Query));
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/* Plan the query if needed */
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if (queryTree->commandType == CMD_UTILITY)
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stmt = queryTree->utilityStmt;
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stmt = (Node *) pg_plan_query(queryTree, 0, NULL);
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/* Precheck all commands for validity in a function */
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if (IsA(stmt, TransactionStmt))
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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/* translator: %s is a SQL statement name */
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errmsg("%s is not allowed in a SQL function",
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CreateCommandTag(stmt))));
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if (fcache->readonly_func && !CommandIsReadOnly(stmt))
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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/* translator: %s is a SQL statement name */
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errmsg("%s is not allowed in a non-volatile function",
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CreateCommandTag(stmt))));
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/* OK, build the execution_state for this query */
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newes = (execution_state *) palloc(sizeof(execution_state));
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preves->next = newes;
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newes->status = F_EXEC_START;
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newes->setsResult = false; /* might change below */
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newes->lazyEval = false; /* might change below */
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if (queryTree->canSetTag)
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eslist = lappend(eslist, firstes);
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* Mark the last canSetTag query as delivering the function result; then,
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* if it is a plain SELECT, mark it for lazy evaluation. If it's not a
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* SELECT we must always run it to completion.
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* Note: at some point we might add additional criteria for whether to use
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* lazy eval. However, we should prefer to use it whenever the function
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* doesn't return set, since fetching more than one row is useless in that
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* Note: don't set setsResult if the function returns VOID, as evidenced
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* by not having made a junkfilter. This ensures we'll throw away any
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* output from a utility statement that check_sql_fn_retval deemed to not
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if (lasttages && fcache->junkFilter)
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lasttages->setsResult = true;
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IsA(lasttages->stmt, PlannedStmt))
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PlannedStmt *ps = (PlannedStmt *) lasttages->stmt;
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if (ps->commandType == CMD_SELECT &&
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ps->utilityStmt == NULL &&
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ps->intoClause == NULL &&
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!ps->hasModifyingCTE)
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fcache->lazyEval = lasttages->lazyEval = true;
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* Initialize the SQLFunctionCache for a SQL function
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init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
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Oid foid = finfo->fn_oid;
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HeapTuple procedureTuple;
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Form_pg_proc procedureStruct;
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SQLFunctionCachePtr fcache;
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List *raw_parsetree_list;
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List *queryTree_list;
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List *flat_query_list;
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fcache = (SQLFunctionCachePtr) palloc0(sizeof(SQLFunctionCache));
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finfo->fn_extra = (void *) fcache;
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* get the procedure tuple corresponding to the given function Oid
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procedureTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(foid));
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if (!HeapTupleIsValid(procedureTuple))
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elog(ERROR, "cache lookup failed for function %u", foid);
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procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
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* copy function name immediately for use by error reporting callback
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fcache->fname = pstrdup(NameStr(procedureStruct->proname));
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* get the result type from the procedure tuple, and check for polymorphic
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* result type; if so, find out the actual result type.
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rettype = procedureStruct->prorettype;
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if (IsPolymorphicType(rettype))
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rettype = get_fn_expr_rettype(finfo);
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if (rettype == InvalidOid) /* this probably should not happen */
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(errcode(ERRCODE_DATATYPE_MISMATCH),
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errmsg("could not determine actual result type for function declared to return type %s",
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format_type_be(procedureStruct->prorettype))));
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fcache->rettype = rettype;
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/* Fetch the typlen and byval info for the result type */
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get_typlenbyval(rettype, &fcache->typlen, &fcache->typbyval);
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/* Remember whether we're returning setof something */
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fcache->returnsSet = procedureStruct->proretset;
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/* Remember if function is STABLE/IMMUTABLE */
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fcache->readonly_func =
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(procedureStruct->provolatile != PROVOLATILE_VOLATILE);
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* We need the actual argument types to pass to the parser. Also make
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* sure that parameter symbols are considered to have the function's
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* resolved input collation.
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fcache->pinfo = prepare_sql_fn_parse_info(procedureTuple,
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* And of course we need the function body text.
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tmp = SysCacheGetAttr(PROCOID,
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elog(ERROR, "null prosrc for function %u", foid);
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fcache->src = TextDatumGetCString(tmp);
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* Parse and rewrite the queries in the function text. Use sublists to
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* keep track of the original query boundaries. But we also build a
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* "flat" list of the rewritten queries to pass to check_sql_fn_retval.
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* This is because the last canSetTag query determines the result type
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* independently of query boundaries --- and it might not be in the last
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* sublist, for example if the last query rewrites to DO INSTEAD NOTHING.
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* (It might not be unreasonable to throw an error in such a case, but
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* this is the historical behavior and it doesn't seem worth changing.)
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raw_parsetree_list = pg_parse_query(fcache->src);
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queryTree_list = NIL;
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flat_query_list = NIL;
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foreach(lc, raw_parsetree_list)
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Node *parsetree = (Node *) lfirst(lc);
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List *queryTree_sublist;
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queryTree_sublist = pg_analyze_and_rewrite_params(parsetree,
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(ParserSetupHook) sql_fn_parser_setup,
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queryTree_list = lappend(queryTree_list, queryTree_sublist);
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flat_query_list = list_concat(flat_query_list,
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list_copy(queryTree_sublist));
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* Check that the function returns the type it claims to. Although in
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* simple cases this was already done when the function was defined, we
475
* have to recheck because database objects used in the function's queries
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* might have changed type. We'd have to do it anyway if the function had
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* any polymorphic arguments.
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* Note: we set fcache->returnsTuple according to whether we are returning
480
* the whole tuple result or just a single column. In the latter case we
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* clear returnsTuple because we need not act different from the scalar
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* result case, even if it's a rowtype column. (However, we have to force
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* lazy eval mode in that case; otherwise we'd need extra code to expand
484
* the rowtype column into multiple columns, since we have no way to
485
* notify the caller that it should do that.)
487
* check_sql_fn_retval will also construct a JunkFilter we can use to
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* coerce the returned rowtype to the desired form (unless the result type
489
* is VOID, in which case there's nothing to coerce to).
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fcache->returnsTuple = check_sql_fn_retval(foid,
495
&fcache->junkFilter);
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if (fcache->returnsTuple)
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/* Make sure output rowtype is properly blessed */
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BlessTupleDesc(fcache->junkFilter->jf_resultSlot->tts_tupleDescriptor);
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else if (fcache->returnsSet && type_is_rowtype(fcache->rettype))
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* Returning rowtype as if it were scalar --- materialize won't work.
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* Right now it's sufficient to override any caller preference for
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* materialize mode, but to add more smarts in init_execution_state
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* about this, we'd probably need a three-way flag instead of bool.
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/* Finally, plan the queries */
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fcache->func_state = init_execution_state(queryTree_list,
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ReleaseSysCache(procedureTuple);
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/* Start up execution of one execution_state node */
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postquel_start(execution_state *es, SQLFunctionCachePtr fcache)
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Assert(es->qd == NULL);
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/* Caller should have ensured a suitable snapshot is active */
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Assert(ActiveSnapshotSet());
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* If this query produces the function result, send its output to the
534
* tuplestore; else discard any output.
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DR_sqlfunction *myState;
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dest = CreateDestReceiver(DestSQLFunction);
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/* pass down the needed info to the dest receiver routines */
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myState = (DR_sqlfunction *) dest;
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Assert(myState->pub.mydest == DestSQLFunction);
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myState->tstore = fcache->tstore;
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myState->cxt = CurrentMemoryContext;
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myState->filter = fcache->junkFilter;
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dest = None_Receiver;
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if (IsA(es->stmt, PlannedStmt))
552
es->qd = CreateQueryDesc((PlannedStmt *) es->stmt,
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es->qd = CreateUtilityQueryDesc(es->stmt,
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/* Utility commands don't need Executor. */
566
if (es->qd->utilitystmt == NULL)
569
* In lazyEval mode, do not let the executor set up an AfterTrigger
570
* context. This is necessary not just an optimization, because we
571
* mustn't exit from the function execution with a stacked
572
* AfterTrigger level still active. We are careful not to select
573
* lazyEval mode for any statement that could possibly queue triggers.
578
eflags = EXEC_FLAG_SKIP_TRIGGERS;
580
eflags = 0; /* default run-to-completion flags */
581
ExecutorStart(es->qd, eflags);
584
es->status = F_EXEC_RUN;
587
/* Run one execution_state; either to completion or to first result row */
588
/* Returns true if we ran to completion */
590
postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache)
594
if (es->qd->utilitystmt)
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/* ProcessUtility needs the PlannedStmt for DECLARE CURSOR */
597
ProcessUtility((es->qd->plannedstmt ?
598
(Node *) es->qd->plannedstmt :
599
es->qd->utilitystmt),
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false, /* not top level */
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result = true; /* never stops early */
609
/* Run regular commands to completion unless lazyEval */
610
long count = (es->lazyEval) ? 1L : 0L;
612
ExecutorRun(es->qd, ForwardScanDirection, count);
615
* If we requested run to completion OR there was no tuple returned,
616
* command must be complete.
618
result = (count == 0L || es->qd->estate->es_processed == 0);
624
/* Shut down execution of one execution_state node */
626
postquel_end(execution_state *es)
628
/* mark status done to ensure we don't do ExecutorEnd twice */
629
es->status = F_EXEC_DONE;
631
/* Utility commands don't need Executor. */
632
if (es->qd->utilitystmt == NULL)
634
ExecutorFinish(es->qd);
638
(*es->qd->dest->rDestroy) (es->qd->dest);
640
FreeQueryDesc(es->qd);
644
/* Build ParamListInfo array representing current arguments */
646
postquel_sub_params(SQLFunctionCachePtr fcache,
647
FunctionCallInfo fcinfo)
649
int nargs = fcinfo->nargs;
653
ParamListInfo paramLI;
656
if (fcache->paramLI == NULL)
658
/* sizeof(ParamListInfoData) includes the first array element */
659
paramLI = (ParamListInfo) palloc(sizeof(ParamListInfoData) +
660
(nargs - 1) * sizeof(ParamExternData));
661
/* we have static list of params, so no hooks needed */
662
paramLI->paramFetch = NULL;
663
paramLI->paramFetchArg = NULL;
664
paramLI->parserSetup = NULL;
665
paramLI->parserSetupArg = NULL;
666
paramLI->numParams = nargs;
667
fcache->paramLI = paramLI;
671
paramLI = fcache->paramLI;
672
Assert(paramLI->numParams == nargs);
675
for (i = 0; i < nargs; i++)
677
ParamExternData *prm = ¶mLI->params[i];
679
prm->value = fcinfo->arg[i];
680
prm->isnull = fcinfo->argnull[i];
682
prm->ptype = fcache->pinfo->argtypes[i];
686
fcache->paramLI = NULL;
690
* Extract the SQL function's value from a single result row. This is used
691
* both for scalar (non-set) functions and for each row of a lazy-eval set
695
postquel_get_single_result(TupleTableSlot *slot,
696
FunctionCallInfo fcinfo,
697
SQLFunctionCachePtr fcache,
698
MemoryContext resultcontext)
701
MemoryContext oldcontext;
704
* Set up to return the function value. For pass-by-reference datatypes,
705
* be sure to allocate the result in resultcontext, not the current memory
706
* context (which has query lifespan). We can't leave the data in the
707
* TupleTableSlot because we intend to clear the slot before returning.
709
oldcontext = MemoryContextSwitchTo(resultcontext);
711
if (fcache->returnsTuple)
713
/* We must return the whole tuple as a Datum. */
714
fcinfo->isnull = false;
715
value = ExecFetchSlotTupleDatum(slot);
716
value = datumCopy(value, fcache->typbyval, fcache->typlen);
721
* Returning a scalar, which we have to extract from the first column
722
* of the SELECT result, and then copy into result context if needed.
724
value = slot_getattr(slot, 1, &(fcinfo->isnull));
727
value = datumCopy(value, fcache->typbyval, fcache->typlen);
730
MemoryContextSwitchTo(oldcontext);
736
* fmgr_sql: function call manager for SQL functions
739
fmgr_sql(PG_FUNCTION_ARGS)
741
MemoryContext oldcontext;
742
SQLFunctionCachePtr fcache;
743
ErrorContextCallback sqlerrcontext;
747
bool pushed_snapshot;
749
TupleTableSlot *slot;
755
* Switch to context in which the fcache lives. This ensures that
756
* parsetrees, plans, etc, will have sufficient lifetime. The
757
* sub-executor is responsible for deleting per-tuple information.
759
oldcontext = MemoryContextSwitchTo(fcinfo->flinfo->fn_mcxt);
762
* Setup error traceback support for ereport()
764
sqlerrcontext.callback = sql_exec_error_callback;
765
sqlerrcontext.arg = fcinfo->flinfo;
766
sqlerrcontext.previous = error_context_stack;
767
error_context_stack = &sqlerrcontext;
769
/* Check call context */
770
if (fcinfo->flinfo->fn_retset)
772
ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
775
* For simplicity, we require callers to support both set eval modes.
776
* There are cases where we must use one or must use the other, and
777
* it's not really worthwhile to postpone the check till we know. But
778
* note we do not require caller to provide an expectedDesc.
780
if (!rsi || !IsA(rsi, ReturnSetInfo) ||
781
(rsi->allowedModes & SFRM_ValuePerCall) == 0 ||
782
(rsi->allowedModes & SFRM_Materialize) == 0)
784
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
785
errmsg("set-valued function called in context that cannot accept a set")));
786
randomAccess = rsi->allowedModes & SFRM_Materialize_Random;
787
lazyEvalOK = !(rsi->allowedModes & SFRM_Materialize_Preferred);
791
randomAccess = false;
796
* Initialize fcache (build plans) if first time through.
798
fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
801
init_sql_fcache(fcinfo->flinfo, PG_GET_COLLATION(), lazyEvalOK);
802
fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
804
eslist = fcache->func_state;
807
* Find first unfinished query in function, and note whether it's the
812
foreach(eslc, eslist)
814
es = (execution_state *) lfirst(eslc);
816
while (es && es->status == F_EXEC_DONE)
827
* Convert params to appropriate format if starting a fresh execution. (If
828
* continuing execution, we can re-use prior params.)
830
if (is_first && es && es->status == F_EXEC_START)
831
postquel_sub_params(fcache, fcinfo);
834
* Build tuplestore to hold results, if we don't have one already. Note
835
* it's in the query-lifespan context.
838
fcache->tstore = tuplestore_begin_heap(randomAccess, false, work_mem);
841
* Execute each command in the function one after another until we either
842
* run out of commands or get a result row from a lazily-evaluated SELECT.
844
* Notes about snapshot management:
846
* In a read-only function, we just use the surrounding query's snapshot.
848
* In a non-read-only function, we rely on the fact that we'll never
849
* suspend execution between queries of the function: the only reason to
850
* suspend execution before completion is if we are returning a row from a
851
* lazily-evaluated SELECT. So, when first entering this loop, we'll
852
* either start a new query (and push a fresh snapshot) or re-establish
853
* the active snapshot from the existing query descriptor. If we need to
854
* start a new query in a subsequent execution of the loop, either we need
855
* a fresh snapshot (and pushed_snapshot is false) or the existing
856
* snapshot is on the active stack and we can just bump its command ID.
858
pushed_snapshot = false;
863
if (es->status == F_EXEC_START)
866
* If not read-only, be sure to advance the command counter for
867
* each command, so that all work to date in this transaction is
868
* visible. Take a new snapshot if we don't have one yet,
869
* otherwise just bump the command ID in the existing snapshot.
871
if (!fcache->readonly_func)
873
CommandCounterIncrement();
874
if (!pushed_snapshot)
876
PushActiveSnapshot(GetTransactionSnapshot());
877
pushed_snapshot = true;
880
UpdateActiveSnapshotCommandId();
883
postquel_start(es, fcache);
885
else if (!fcache->readonly_func && !pushed_snapshot)
887
/* Re-establish active snapshot when re-entering function */
888
PushActiveSnapshot(es->qd->snapshot);
889
pushed_snapshot = true;
892
completed = postquel_getnext(es, fcache);
895
* If we ran the command to completion, we can shut it down now. Any
896
* row(s) we need to return are safely stashed in the tuplestore, and
897
* we want to be sure that, for example, AFTER triggers get fired
898
* before we return anything. Also, if the function doesn't return
899
* set, we can shut it down anyway because it must be a SELECT and we
900
* don't care about fetching any more result rows.
902
if (completed || !fcache->returnsSet)
906
* Break from loop if we didn't shut down (implying we got a
907
* lazily-evaluated row). Otherwise we'll press on till the whole
908
* function is done, relying on the tuplestore to keep hold of the
909
* data to eventually be returned. This is necessary since an
910
* INSERT/UPDATE/DELETE RETURNING that sets the result might be
911
* followed by additional rule-inserted commands, and we want to
912
* finish doing all those commands before we return anything.
914
if (es->status != F_EXEC_DONE)
918
* Advance to next execution_state, which might be in the next list.
925
break; /* end of function */
927
es = (execution_state *) lfirst(eslc);
930
* Flush the current snapshot so that we will take a new one for
931
* the new query list. This ensures that new snaps are taken at
932
* original-query boundaries, matching the behavior of interactive
938
pushed_snapshot = false;
944
* The tuplestore now contains whatever row(s) we are supposed to return.
946
if (fcache->returnsSet)
948
ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
953
* If we stopped short of being done, we must have a lazy-eval
956
Assert(es->lazyEval);
957
/* Re-use the junkfilter's output slot to fetch back the tuple */
958
Assert(fcache->junkFilter);
959
slot = fcache->junkFilter->jf_resultSlot;
960
if (!tuplestore_gettupleslot(fcache->tstore, true, false, slot))
961
elog(ERROR, "failed to fetch lazy-eval tuple");
962
/* Extract the result as a datum, and copy out from the slot */
963
result = postquel_get_single_result(slot, fcinfo,
965
/* Clear the tuplestore, but keep it for next time */
966
/* NB: this might delete the slot's content, but we don't care */
967
tuplestore_clear(fcache->tstore);
970
* Let caller know we're not finished.
972
rsi->isDone = ExprMultipleResult;
975
* Ensure we will get shut down cleanly if the exprcontext is not
978
if (!fcache->shutdown_reg)
980
RegisterExprContextCallback(rsi->econtext,
982
PointerGetDatum(fcache));
983
fcache->shutdown_reg = true;
986
else if (fcache->lazyEval)
989
* We are done with a lazy evaluation. Clean up.
991
tuplestore_clear(fcache->tstore);
994
* Let caller know we're finished.
996
rsi->isDone = ExprEndResult;
998
fcinfo->isnull = true;
1001
/* Deregister shutdown callback, if we made one */
1002
if (fcache->shutdown_reg)
1004
UnregisterExprContextCallback(rsi->econtext,
1005
ShutdownSQLFunction,
1006
PointerGetDatum(fcache));
1007
fcache->shutdown_reg = false;
1013
* We are done with a non-lazy evaluation. Return whatever is in
1014
* the tuplestore. (It is now caller's responsibility to free the
1015
* tuplestore when done.)
1017
rsi->returnMode = SFRM_Materialize;
1018
rsi->setResult = fcache->tstore;
1019
fcache->tstore = NULL;
1020
/* must copy desc because execQual will free it */
1021
if (fcache->junkFilter)
1022
rsi->setDesc = CreateTupleDescCopy(fcache->junkFilter->jf_cleanTupType);
1024
fcinfo->isnull = true;
1027
/* Deregister shutdown callback, if we made one */
1028
if (fcache->shutdown_reg)
1030
UnregisterExprContextCallback(rsi->econtext,
1031
ShutdownSQLFunction,
1032
PointerGetDatum(fcache));
1033
fcache->shutdown_reg = false;
1040
* Non-set function. If we got a row, return it; else return NULL.
1042
if (fcache->junkFilter)
1044
/* Re-use the junkfilter's output slot to fetch back the tuple */
1045
slot = fcache->junkFilter->jf_resultSlot;
1046
if (tuplestore_gettupleslot(fcache->tstore, true, false, slot))
1047
result = postquel_get_single_result(slot, fcinfo,
1048
fcache, oldcontext);
1051
fcinfo->isnull = true;
1057
/* Should only get here for VOID functions */
1058
Assert(fcache->rettype == VOIDOID);
1059
fcinfo->isnull = true;
1063
/* Clear the tuplestore, but keep it for next time */
1064
tuplestore_clear(fcache->tstore);
1067
/* Pop snapshot if we have pushed one */
1068
if (pushed_snapshot)
1069
PopActiveSnapshot();
1072
* If we've gone through every command in the function, we are done. Reset
1073
* the execution states to start over again on next call.
1077
foreach(eslc, fcache->func_state)
1079
es = (execution_state *) lfirst(eslc);
1082
es->status = F_EXEC_START;
1088
error_context_stack = sqlerrcontext.previous;
1090
MemoryContextSwitchTo(oldcontext);
1097
* error context callback to let us supply a call-stack traceback
1100
sql_exec_error_callback(void *arg)
1102
FmgrInfo *flinfo = (FmgrInfo *) arg;
1103
SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) flinfo->fn_extra;
1104
int syntaxerrposition;
1107
* We can do nothing useful if init_sql_fcache() didn't get as far as
1108
* saving the function name
1110
if (fcache == NULL || fcache->fname == NULL)
1114
* If there is a syntax error position, convert to internal syntax error
1116
syntaxerrposition = geterrposition();
1117
if (syntaxerrposition > 0 && fcache->src != NULL)
1120
internalerrposition(syntaxerrposition);
1121
internalerrquery(fcache->src);
1125
* Try to determine where in the function we failed. If there is a query
1126
* with non-null QueryDesc, finger it. (We check this rather than looking
1127
* for F_EXEC_RUN state, so that errors during ExecutorStart or
1128
* ExecutorEnd are blamed on the appropriate query; see postquel_start and
1131
if (fcache->func_state)
1133
execution_state *es;
1139
foreach(lc, fcache->func_state)
1141
es = (execution_state *) lfirst(lc);
1146
errcontext("SQL function \"%s\" statement %d",
1147
fcache->fname, query_num);
1159
* couldn't identify a running query; might be function entry,
1160
* function exit, or between queries.
1162
errcontext("SQL function \"%s\"", fcache->fname);
1168
* Assume we failed during init_sql_fcache(). (It's possible that the
1169
* function actually has an empty body, but in that case we may as
1170
* well report all errors as being "during startup".)
1172
errcontext("SQL function \"%s\" during startup", fcache->fname);
1178
* callback function in case a function-returning-set needs to be shut down
1179
* before it has been run to completion
1182
ShutdownSQLFunction(Datum arg)
1184
SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) DatumGetPointer(arg);
1185
execution_state *es;
1188
foreach(lc, fcache->func_state)
1190
es = (execution_state *) lfirst(lc);
1193
/* Shut down anything still running */
1194
if (es->status == F_EXEC_RUN)
1196
/* Re-establish active snapshot for any called functions */
1197
if (!fcache->readonly_func)
1198
PushActiveSnapshot(es->qd->snapshot);
1202
if (!fcache->readonly_func)
1203
PopActiveSnapshot();
1206
/* Reset states to START in case we're called again */
1207
es->status = F_EXEC_START;
1212
/* Release tuplestore if we have one */
1214
tuplestore_end(fcache->tstore);
1215
fcache->tstore = NULL;
1217
/* execUtils will deregister the callback... */
1218
fcache->shutdown_reg = false;
1223
* check_sql_fn_retval() -- check return value of a list of sql parse trees.
1225
* The return value of a sql function is the value returned by the last
1226
* canSetTag query in the function. We do some ad-hoc type checking here
1227
* to be sure that the user is returning the type he claims. There are
1228
* also a couple of strange-looking features to assist callers in dealing
1229
* with allowed special cases, such as binary-compatible result types.
1231
* For a polymorphic function the passed rettype must be the actual resolved
1232
* output type of the function; we should never see a polymorphic pseudotype
1233
* such as ANYELEMENT as rettype. (This means we can't check the type during
1234
* function definition of a polymorphic function.)
1236
* This function returns true if the sql function returns the entire tuple
1237
* result of its final statement, or false if it returns just the first column
1238
* result of that statement. It throws an error if the final statement doesn't
1239
* return the right type at all.
1241
* Note that because we allow "SELECT rowtype_expression", the result can be
1242
* false even when the declared function return type is a rowtype.
1244
* If modifyTargetList isn't NULL, the function will modify the final
1245
* statement's targetlist in two cases:
1246
* (1) if the tlist returns values that are binary-coercible to the expected
1247
* type rather than being exactly the expected type. RelabelType nodes will
1248
* be inserted to make the result types match exactly.
1249
* (2) if there are dropped columns in the declared result rowtype. NULL
1250
* output columns will be inserted in the tlist to match them.
1251
* (Obviously the caller must pass a parsetree that is okay to modify when
1252
* using this flag.) Note that this flag does not affect whether the tlist is
1253
* considered to be a legal match to the result type, only how we react to
1254
* allowed not-exact-match cases. *modifyTargetList will be set true iff
1255
* we had to make any "dangerous" changes that could modify the semantics of
1256
* the statement. If it is set true, the caller should not use the modified
1257
* statement, but for simplicity we apply the changes anyway.
1259
* If junkFilter isn't NULL, then *junkFilter is set to a JunkFilter defined
1260
* to convert the function's tuple result to the correct output tuple type.
1261
* Exception: if the function is defined to return VOID then *junkFilter is
1265
check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
1266
bool *modifyTargetList,
1267
JunkFilter **junkFilter)
1277
AssertArg(!IsPolymorphicType(rettype));
1279
if (modifyTargetList)
1280
*modifyTargetList = false; /* initialize for no change */
1282
*junkFilter = NULL; /* initialize in case of VOID result */
1285
* Find the last canSetTag query in the list. This isn't necessarily the
1286
* last parsetree, because rule rewriting can insert queries after what
1290
foreach(lc, queryTreeList)
1292
Query *q = (Query *) lfirst(lc);
1299
* If it's a plain SELECT, it returns whatever the targetlist says.
1300
* Otherwise, if it's INSERT/UPDATE/DELETE with RETURNING, it returns
1301
* that. Otherwise, the function return type must be VOID.
1303
* Note: eventually replace this test with QueryReturnsTuples? We'd need
1304
* a more general method of determining the output type, though. Also, it
1305
* seems too dangerous to consider FETCH or EXECUTE as returning a
1306
* determinable rowtype, since they depend on relatively short-lived
1310
parse->commandType == CMD_SELECT &&
1311
parse->utilityStmt == NULL &&
1312
parse->intoClause == NULL)
1314
tlist_ptr = &parse->targetList;
1315
tlist = parse->targetList;
1318
(parse->commandType == CMD_INSERT ||
1319
parse->commandType == CMD_UPDATE ||
1320
parse->commandType == CMD_DELETE) &&
1321
parse->returningList)
1323
tlist_ptr = &parse->returningList;
1324
tlist = parse->returningList;
1328
/* Empty function body, or last statement is a utility command */
1329
if (rettype != VOIDOID)
1331
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1332
errmsg("return type mismatch in function declared to return %s",
1333
format_type_be(rettype)),
1334
errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE RETURNING.")));
1339
* OK, check that the targetlist returns something matching the declared
1340
* type. (We used to insist that the declared type not be VOID in this
1341
* case, but that makes it hard to write a void function that exits after
1342
* calling another void function. Instead, we insist that the tlist
1343
* return void ... so void is treated as if it were a scalar type below.)
1347
* Count the non-junk entries in the result targetlist.
1349
tlistlen = ExecCleanTargetListLength(tlist);
1351
fn_typtype = get_typtype(rettype);
1353
if (fn_typtype == TYPTYPE_BASE ||
1354
fn_typtype == TYPTYPE_DOMAIN ||
1355
fn_typtype == TYPTYPE_ENUM ||
1359
* For scalar-type returns, the target list must have exactly one
1360
* non-junk entry, and its type must agree with what the user
1361
* declared; except we allow binary-compatible types too.
1367
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1368
errmsg("return type mismatch in function declared to return %s",
1369
format_type_be(rettype)),
1370
errdetail("Final statement must return exactly one column.")));
1372
/* We assume here that non-junk TLEs must come first in tlists */
1373
tle = (TargetEntry *) linitial(tlist);
1374
Assert(!tle->resjunk);
1376
restype = exprType((Node *) tle->expr);
1377
if (!IsBinaryCoercible(restype, rettype))
1379
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1380
errmsg("return type mismatch in function declared to return %s",
1381
format_type_be(rettype)),
1382
errdetail("Actual return type is %s.",
1383
format_type_be(restype))));
1384
if (modifyTargetList && restype != rettype)
1386
tle->expr = (Expr *) makeRelabelType(tle->expr,
1389
get_typcollation(rettype),
1391
/* Relabel is dangerous if TLE is a sort/group or setop column */
1392
if (tle->ressortgroupref != 0 || parse->setOperations)
1393
*modifyTargetList = true;
1396
/* Set up junk filter if needed */
1398
*junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1400
else if (fn_typtype == TYPTYPE_COMPOSITE || rettype == RECORDOID)
1402
/* Returns a rowtype */
1404
int tupnatts; /* physical number of columns in tuple */
1405
int tuplogcols; /* # of nondeleted columns in tuple */
1406
int colindex; /* physical column index */
1407
List *newtlist; /* new non-junk tlist entries */
1408
List *junkattrs; /* new junk tlist entries */
1411
* If the target list is of length 1, and the type of the varnode in
1412
* the target list matches the declared return type, this is okay.
1413
* This can happen, for example, where the body of the function is
1414
* 'SELECT func2()', where func2 has the same composite return type as
1415
* the function that's calling it.
1417
* XXX Note that if rettype is RECORD, the IsBinaryCoercible check
1418
* will succeed for any composite restype. For the moment we rely on
1419
* runtime type checking to catch any discrepancy, but it'd be nice to
1420
* do better at parse time.
1424
TargetEntry *tle = (TargetEntry *) linitial(tlist);
1426
Assert(!tle->resjunk);
1427
restype = exprType((Node *) tle->expr);
1428
if (IsBinaryCoercible(restype, rettype))
1430
if (modifyTargetList && restype != rettype)
1432
tle->expr = (Expr *) makeRelabelType(tle->expr,
1435
get_typcollation(rettype),
1437
/* Relabel is dangerous if sort/group or setop column */
1438
if (tle->ressortgroupref != 0 || parse->setOperations)
1439
*modifyTargetList = true;
1441
/* Set up junk filter if needed */
1443
*junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1444
return false; /* NOT returning whole tuple */
1448
/* Is the rowtype fixed, or determined only at runtime? */
1449
if (get_func_result_type(func_id, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
1452
* Assume we are returning the whole tuple. Crosschecking against
1453
* what the caller expects will happen at runtime.
1456
*junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1462
* Verify that the targetlist matches the return tuple type. We scan
1463
* the non-deleted attributes to ensure that they match the datatypes
1464
* of the non-resjunk columns. For deleted attributes, insert NULL
1465
* result columns if the caller asked for that.
1467
tupnatts = tupdesc->natts;
1468
tuplogcols = 0; /* we'll count nondeleted cols as we go */
1470
newtlist = NIL; /* these are only used if modifyTargetList */
1475
TargetEntry *tle = (TargetEntry *) lfirst(lc);
1476
Form_pg_attribute attr;
1482
if (modifyTargetList)
1483
junkattrs = lappend(junkattrs, tle);
1490
if (colindex > tupnatts)
1492
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1493
errmsg("return type mismatch in function declared to return %s",
1494
format_type_be(rettype)),
1495
errdetail("Final statement returns too many columns.")));
1496
attr = tupdesc->attrs[colindex - 1];
1497
if (attr->attisdropped && modifyTargetList)
1501
/* The type of the null we insert isn't important */
1502
null_expr = (Expr *) makeConst(INT4OID,
1509
newtlist = lappend(newtlist,
1510
makeTargetEntry(null_expr,
1514
/* NULL insertion is dangerous in a setop */
1515
if (parse->setOperations)
1516
*modifyTargetList = true;
1518
} while (attr->attisdropped);
1521
tletype = exprType((Node *) tle->expr);
1522
atttype = attr->atttypid;
1523
if (!IsBinaryCoercible(tletype, atttype))
1525
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1526
errmsg("return type mismatch in function declared to return %s",
1527
format_type_be(rettype)),
1528
errdetail("Final statement returns %s instead of %s at column %d.",
1529
format_type_be(tletype),
1530
format_type_be(atttype),
1532
if (modifyTargetList)
1534
if (tletype != atttype)
1536
tle->expr = (Expr *) makeRelabelType(tle->expr,
1539
get_typcollation(atttype),
1541
/* Relabel is dangerous if sort/group or setop column */
1542
if (tle->ressortgroupref != 0 || parse->setOperations)
1543
*modifyTargetList = true;
1545
tle->resno = colindex;
1546
newtlist = lappend(newtlist, tle);
1550
/* remaining columns in tupdesc had better all be dropped */
1551
for (colindex++; colindex <= tupnatts; colindex++)
1553
if (!tupdesc->attrs[colindex - 1]->attisdropped)
1555
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1556
errmsg("return type mismatch in function declared to return %s",
1557
format_type_be(rettype)),
1558
errdetail("Final statement returns too few columns.")));
1559
if (modifyTargetList)
1563
/* The type of the null we insert isn't important */
1564
null_expr = (Expr *) makeConst(INT4OID,
1571
newtlist = lappend(newtlist,
1572
makeTargetEntry(null_expr,
1576
/* NULL insertion is dangerous in a setop */
1577
if (parse->setOperations)
1578
*modifyTargetList = true;
1582
if (modifyTargetList)
1584
/* ensure resjunk columns are numbered correctly */
1585
foreach(lc, junkattrs)
1587
TargetEntry *tle = (TargetEntry *) lfirst(lc);
1589
tle->resno = colindex++;
1591
/* replace the tlist with the modified one */
1592
*tlist_ptr = list_concat(newtlist, junkattrs);
1595
/* Set up junk filter if needed */
1597
*junkFilter = ExecInitJunkFilterConversion(tlist,
1598
CreateTupleDescCopy(tupdesc),
1601
/* Report that we are returning entire tuple result */
1606
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1607
errmsg("return type %s is not supported for SQL functions",
1608
format_type_be(rettype))));
1615
* CreateSQLFunctionDestReceiver -- create a suitable DestReceiver object
1618
CreateSQLFunctionDestReceiver(void)
1620
DR_sqlfunction *self = (DR_sqlfunction *) palloc0(sizeof(DR_sqlfunction));
1622
self->pub.receiveSlot = sqlfunction_receive;
1623
self->pub.rStartup = sqlfunction_startup;
1624
self->pub.rShutdown = sqlfunction_shutdown;
1625
self->pub.rDestroy = sqlfunction_destroy;
1626
self->pub.mydest = DestSQLFunction;
1628
/* private fields will be set by postquel_start */
1630
return (DestReceiver *) self;
1634
* sqlfunction_startup --- executor startup
1637
sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
1643
* sqlfunction_receive --- receive one tuple
1646
sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self)
1648
DR_sqlfunction *myState = (DR_sqlfunction *) self;
1650
/* Filter tuple as needed */
1651
slot = ExecFilterJunk(myState->filter, slot);
1653
/* Store the filtered tuple into the tuplestore */
1654
tuplestore_puttupleslot(myState->tstore, slot);
1658
* sqlfunction_shutdown --- executor end
1661
sqlfunction_shutdown(DestReceiver *self)
1667
* sqlfunction_destroy --- release DestReceiver object
1670
sqlfunction_destroy(DestReceiver *self)
added
removed
src/backend/executor/functions.c
