Files
openGauss-server/src/gausskernel/runtime/executor/functions.cpp
2021-03-06 12:39:28 +08:00

1830 lines
69 KiB
C++

/* -------------------------------------------------------------------------
*
* functions.cpp
* Execution of SQL-language functions
*
* Portions Copyright (c) 2020 Huawei Technologies Co.,Ltd.
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/gausskernel/runtime/executor/functions.cpp
*
* -------------------------------------------------------------------------
*/
#include "postgres.h"
#include "knl/knl_variable.h"
#include "access/transam.h"
#include "access/tableam.h"
#include "access/xact.h"
#include "auditfuncs.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_func.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"
#ifdef STREAMPLAN
#include "optimizer/streamplan.h"
#endif
#ifdef PGXC
#include "pgxc/pgxc.h"
#include "commands/prepare.h"
#endif
#include "securec.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 */
Node* stmt; /* PlannedStmt or utility statement */
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;
/*
* Data structure needed by the parser callback hooks to resolve parameter
* references during parsing of a SQL function's body. This is separate from
* SQLFunctionCache since we sometimes do parsing separately from execution.
*/
typedef struct SQLFunctionParseInfo {
char* fname; /* function's name */
int nargs; /* number of input arguments */
Oid* argtypes; /* resolved types of input arguments */
char** argnames; /* names of input arguments; NULL if none */
/* Note that argnames[i] can be NULL, if some args are unnamed */
Oid collation; /* function's input collation, if known */
} SQLFunctionParseInfo;
/* non-export function prototypes */
static Node* sql_fn_param_ref(ParseState* p_state, ParamRef* p_ref);
static Node* sql_fn_post_column_ref(ParseState* p_state, ColumnRef* c_ref, Node* var);
static Node* sql_fn_make_param(SQLFunctionParseInfoPtr p_info, int param_no, int location);
static Node* sql_fn_resolve_param_name(SQLFunctionParseInfoPtr p_info, const char* param_name, int location);
static List* init_execution_state(List* query_tree_list, SQLFunctionCachePtr fcache, bool lazy_eval_ok);
static void init_sql_fcache(FmgrInfo* finfo, Oid collation, bool lazy_eval_ok);
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 result_context);
static void sql_exec_error_callback(void* arg);
static void ShutdownSQLFunction(Datum arg);
static void sqlfunction_startup(DestReceiver* self, int operation, TupleDesc type_info);
static void 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 procedure_tuple, Node* call_expr, Oid input_collation)
{
SQLFunctionParseInfoPtr p_info;
Form_pg_proc procedure_struct = (Form_pg_proc)GETSTRUCT(procedure_tuple);
int nargs;
p_info = (SQLFunctionParseInfoPtr)palloc0(sizeof(SQLFunctionParseInfo));
/* Function's name (only) can be used to qualify argument names */
p_info->fname = pstrdup(NameStr(procedure_struct->proname));
/* Save the function's input collation */
p_info->collation = input_collation;
/*
* Copy input argument types from the pg_proc entry, then resolve any
* polymorphic types.
*/
p_info->nargs = nargs = procedure_struct->pronargs;
if (nargs <= 0) {
p_info->argnames = NULL;
return p_info;
}
Oid* arg_oid_vect = NULL;
int arg_num;
errno_t rc = EOK;
arg_oid_vect = (Oid*)palloc(nargs * sizeof(Oid));
rc = memcpy_s(arg_oid_vect, nargs * sizeof(Oid), procedure_struct->proargtypes.values, nargs * sizeof(Oid));
securec_check(rc, "\0", "\0");
for (arg_num = 0; arg_num < nargs; arg_num++) {
Oid arg_type = arg_oid_vect[arg_num];
if (IsPolymorphicType(arg_type)) {
arg_type = get_call_expr_argtype(call_expr, arg_num);
if (arg_type == InvalidOid) {
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("could not determine actual type of argument declared %s",
format_type_be(arg_oid_vect[arg_num]))));
}
arg_oid_vect[arg_num] = arg_type;
}
}
p_info->argtypes = arg_oid_vect;
/*
* Collect names of arguments, too, if any
*/
Datum pro_arg_names;
Datum pro_arg_modes;
int n_arg_names;
bool is_null = false;
pro_arg_names = SysCacheGetAttr(PROCNAMEARGSNSP, procedure_tuple, Anum_pg_proc_proargnames, &is_null);
if (is_null) {
pro_arg_names = PointerGetDatum(NULL); /* just to be sure */
}
pro_arg_modes = SysCacheGetAttr(PROCNAMEARGSNSP, procedure_tuple, Anum_pg_proc_proargmodes, &is_null);
if (is_null) {
pro_arg_modes = PointerGetDatum(NULL); /* just to be sure */
}
n_arg_names = get_func_input_arg_names(pro_arg_names, pro_arg_modes, &p_info->argnames);
/* Paranoia: ignore the result if too few array entries */
if (n_arg_names < nargs) {
p_info->argnames = NULL;
}
return p_info;
}
/*
* Parser setup hook for parsing a SQL function body.
*/
void sql_fn_parser_setup(struct ParseState* p_state, SQLFunctionParseInfoPtr p_info)
{
p_state->p_pre_columnref_hook = NULL;
p_state->p_post_columnref_hook = sql_fn_post_column_ref;
p_state->p_paramref_hook = sql_fn_param_ref;
/* no need to use p_coerce_param_hook */
p_state->p_ref_hook_state = (void*)p_info;
}
/*
* sql_fn_post_column_ref parser callback for ColumnRefs
*/
static Node* sql_fn_post_column_ref(ParseState* p_state, ColumnRef* c_ref, Node* var)
{
SQLFunctionParseInfoPtr p_info = (SQLFunctionParseInfoPtr)p_state->p_ref_hook_state;
int n_names;
Node* field1 = NULL;
Node* sub_field = NULL;
const char* name1 = NULL;
const char* name2 = NULL;
Node* param = NULL;
/*
* 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.
* ----------
*/
n_names = list_length(c_ref->fields);
if (n_names > 3)
return NULL;
if (IsA(llast(c_ref->fields), A_Star))
n_names--;
field1 = (Node*)linitial(c_ref->fields);
Assert(IsA(field1, String));
name1 = strVal(field1);
if (n_names > 1) {
sub_field = (Node*)lsecond(c_ref->fields);
Assert(IsA(sub_field, String));
name2 = strVal(sub_field);
}
if (n_names == 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, p_info->fname) != 0)
return NULL;
param = sql_fn_resolve_param_name(p_info, name2, c_ref->location);
sub_field = (Node*)lthird(c_ref->fields);
Assert(IsA(sub_field, String));
} else if (n_names == 2 && strcmp(name1, p_info->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(p_info, name2, c_ref->location);
if (param != NULL) {
/* Yes, so this is a parameter reference, no subfield */
sub_field = NULL;
} else {
/* No, so try to match as parameter name and subfield */
param = sql_fn_resolve_param_name(p_info, name1, c_ref->location);
}
} else {
/* Single name, or parameter name followed by subfield */
param = sql_fn_resolve_param_name(p_info, name1, c_ref->location);
}
if (param == NULL)
return NULL; /* No match */
if (sub_field != NULL) {
/*
* 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(p_state, list_make1(sub_field), list_make1(param), NULL, c_ref->location);
}
return param;
}
/*
* sql_fn_param_ref parser callback for ParamRefs ($n symbols)
*/
static Node* sql_fn_param_ref(ParseState* p_state, ParamRef* p_ref)
{
SQLFunctionParseInfoPtr p_info = (SQLFunctionParseInfoPtr)p_state->p_ref_hook_state;
int param_no = p_ref->number;
/* Check parameter number is valid */
if (param_no <= 0 || param_no > p_info->nargs)
return NULL; /* unknown parameter number */
return sql_fn_make_param(p_info, param_no, p_ref->location);
}
/*
* sql_fn_make_param construct a Param node for the given paramno
*/
static Node* sql_fn_make_param(SQLFunctionParseInfoPtr p_info, int param_no, int location)
{
Param* param = NULL;
param = makeNode(Param);
param->paramkind = PARAM_EXTERN;
param->paramid = param_no;
param->paramtype = p_info->argtypes[param_no - 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(p_info->collation) && OidIsValid(param->paramcollid))
param->paramcollid = p_info->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 p_info, const char* param_name, int location)
{
int i;
if (p_info->argnames == NULL)
return NULL;
if (param_name == NULL) {
ereport(ERROR, (errcode(ERRCODE_UNEXPECTED_NULL_VALUE), errmsg("paramname should not be NULL")));
}
for (i = 0; i < p_info->nargs; i++) {
if (p_info->argnames[i] && strcmp(p_info->argnames[i], param_name) == 0)
return sql_fn_make_param(p_info, 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* query_tree_list, SQLFunctionCachePtr fcache, bool lazy_eval_ok)
{
List* es_list = NIL;
execution_state* last_tages = NULL;
ListCell* lc1 = NULL;
foreach (lc1, query_tree_list) {
List* qt_list = (List*)lfirst(lc1);
execution_state* first_es = NULL;
execution_state* prev_es = NULL;
ListCell* lc2 = NULL;
foreach (lc2, qt_list) {
Query* query_tree = (Query*)lfirst(lc2);
Node* stmt = NULL;
execution_state* new_es = NULL;
Assert(IsA(query_tree, Query));
/* Plan the query if needed */
if (query_tree->commandType == CMD_UTILITY)
stmt = query_tree->utilityStmt;
else
stmt = (Node*)pg_plan_query(query_tree, 0, NULL);
/* Precheck all commands for validity in a function */
if (IsA(stmt, TransactionStmt))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
/* translator: %s is a SQL statement name */
errmsg("%s is not allowed in a SQL function", CreateCommandTag(stmt))));
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", CreateCommandTag(stmt))));
/* OK, build the execution_state for this query */
new_es = (execution_state*)palloc(sizeof(execution_state));
if (prev_es != NULL)
prev_es->next = new_es;
else
first_es = new_es;
new_es->next = NULL;
new_es->status = F_EXEC_START;
new_es->setsResult = false; /* might change below */
new_es->lazyEval = false; /* might change below */
new_es->stmt = stmt;
new_es->qd = NULL;
if (query_tree->canSetTag)
last_tages = new_es;
prev_es = new_es;
}
es_list = lappend(es_list, first_es);
}
/*
* 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 a utility statement that check_sql_fn_retval deemed to not
* have output.
*/
if (last_tages != NULL && fcache->junkFilter) {
last_tages->setsResult = true;
if (lazy_eval_ok && IsA(last_tages->stmt, PlannedStmt)) {
PlannedStmt* ps = (PlannedStmt*)last_tages->stmt;
if (ps->commandType == CMD_SELECT && ps->utilityStmt == NULL && !ps->hasModifyingCTE)
fcache->lazyEval = last_tages->lazyEval = true;
}
}
return es_list;
}
/*
* Initialize the SQLFunctionCache for a SQL function
*/
static void init_sql_fcache(FmgrInfo* finfo, Oid collation, bool lazy_eval_ok)
{
Oid f_oid = finfo->fn_oid;
MemoryContext f_context;
MemoryContext old_context;
Oid ret_type;
HeapTuple procedure_tuple;
Form_pg_proc procedure_struct;
SQLFunctionCachePtr fcache;
List* raw_parsetree_list = NIL;
List* query_tree_list = NIL;
List* flat_query_list = NIL;
ListCell* lc = NULL;
Datum tmp;
bool is_null = false;
/*
* Create memory context that holds all the SQLFunctionCache data. It
* must be a child of whatever context holds the FmgrInfo.
*/
f_context = AllocSetContextCreate(finfo->fn_mcxt,
"SQL function data",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
old_context = MemoryContextSwitchTo(f_context);
/*
* 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 = f_context;
finfo->fn_extra = (void*)fcache;
/*
* get the procedure tuple corresponding to the given function Oid
*/
procedure_tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(f_oid));
if (!HeapTupleIsValid(procedure_tuple))
ereport(ERROR,
(errcode(ERRCODE_CACHE_LOOKUP_FAILED),
errmodule(MOD_EXECUTOR),
errmsg("cache lookup failed for function %u when initialize function cache.", f_oid)));
procedure_struct = (Form_pg_proc)GETSTRUCT(procedure_tuple);
/*
* copy function name immediately for use by error reporting callback
*/
fcache->fname = pstrdup(NameStr(procedure_struct->proname));
/*
* get the result type from the procedure tuple, and check for polymorphic
* result type; if so, find out the actual result type.
*/
ret_type = procedure_struct->prorettype;
if (IsPolymorphicType(ret_type)) {
ret_type = get_fn_expr_rettype(finfo);
if (ret_type == InvalidOid) /* this probably should not happen */
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("could not determine actual result type for function declared to return type %s",
format_type_be(procedure_struct->prorettype))));
}
fcache->rettype = ret_type;
/* Fetch the typlen and byval info for the result type */
get_typlenbyval(ret_type, &fcache->typlen, &fcache->typbyval);
/* Remember whether we're returning setof something */
fcache->returnsSet = procedure_struct->proretset;
/* Remember if function is STABLE/IMMUTABLE */
fcache->readonly_func = (procedure_struct->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(procedure_tuple, finfo->fn_expr, collation);
/*
* And of course we need the function body text.
*/
tmp = SysCacheGetAttr(PROCOID, procedure_tuple, Anum_pg_proc_prosrc, &is_null);
if (is_null)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("null prosrc for function %u when we need the function body text", f_oid)));
fcache->src = TextDatumGetCString(tmp);
/*
* Parse and rewrite the queries in the function text. Use sublists to
* keep track of the original query boundaries. But we also build a
* "flat" list of the rewritten queries to pass to check_sql_fn_retval.
* This is because the last canSetTag query determines the result type
* independently of query boundaries --- and it might not 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.)
*
* 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.
*/
raw_parsetree_list = pg_parse_query(fcache->src);
query_tree_list = NIL;
flat_query_list = NIL;
foreach (lc, raw_parsetree_list) {
Node* parsetree = (Node*)lfirst(lc);
List* queryTree_sublist = NIL;
queryTree_sublist =
pg_analyze_and_rewrite_params(parsetree, fcache->src, (ParserSetupHook)sql_fn_parser_setup, fcache->pinfo);
query_tree_list = lappend(query_tree_list, queryTree_sublist);
flat_query_list = list_concat(flat_query_list, list_copy(queryTree_sublist));
}
/*
* 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 do it anyway if the function had
* any polymorphic arguments.
*
* 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.)
*
* check_sql_fn_retval will also 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).
*/
fcache->returnsTuple = check_sql_fn_retval(f_oid, ret_type, flat_query_list, NULL, &fcache->junkFilter);
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.
*/
lazy_eval_ok = true;
}
/* Finally, plan the queries */
fcache->func_state = init_execution_state(query_tree_list, fcache, lazy_eval_ok);
/* Mark fcache with time of creation to show it's valid */
fcache->lxid = t_thrd.proc->lxid;
fcache->subxid = GetCurrentSubTransactionId();
ReleaseSysCache(procedure_tuple);
MemoryContextSwitchTo(old_context);
}
/* Start up execution of one execution_state node */
static void postquel_start(execution_state* es, SQLFunctionCachePtr fcache)
{
DestReceiver* dest = NULL;
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* my_state = NULL;
dest = CreateDestReceiver(DestSQLFunction);
/* pass down the needed info to the dest receiver routines */
my_state = (DR_sqlfunction*)dest;
Assert(my_state->pub.mydest == DestSQLFunction);
my_state->tstore = fcache->tstore;
my_state->cxt = CurrentMemoryContext;
my_state->filter = fcache->junkFilter;
} else {
dest = None_Receiver;
}
if (IsA(es->stmt, PlannedStmt)) {
es->qd = CreateQueryDesc(
(PlannedStmt*)es->stmt, fcache->src, GetActiveSnapshot(), InvalidSnapshot, dest, fcache->paramLI, 0);
} else {
es->qd = CreateUtilityQueryDesc(es->stmt, fcache->src, GetActiveSnapshot(), dest, fcache->paramLI);
}
/* Utility commands don't need Executor. */
if (es->qd->utilitystmt == NULL) {
/*
* 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 = false;
/* initialize the parameters of the main statement */
Qid stroed_proc_qid = {0, 0, 0};
unsigned char stroed_proc_parctl_state_except = 0;
WLMStatusTag stroed_proc_g_collect_info_status = WLM_STATUS_RESERVE;
bool stroed_proc_is_active_statements_reset = false;
errno_t rc = EOK;
if (es->qd->utilitystmt) {
/* ProcessUtility needs the PlannedStmt for DECLARE CURSOR */
ProcessUtility((es->qd->plannedstmt ? (Node*)es->qd->plannedstmt : es->qd->utilitystmt),
fcache->src,
es->qd->params,
false, /* not top level */
es->qd->dest,
#ifdef PGXC
false,
#endif /* PGXC */
NULL);
result = true; /* never stops early */
} else {
/* Run regular commands to completion unless lazyEval */
long count = (es->lazyEval) ? 1L : 0L;
bool forced_control = (t_thrd.wlm_cxt.parctl_state.simple == 1 || u_sess->wlm_cxt->is_active_statements_reset);
if (ENABLE_WORKLOAD_CONTROL && IS_PGXC_COORDINATOR && forced_control) {
if (!u_sess->wlm_cxt->is_active_statements_reset && !u_sess->attr.attr_resource.enable_transaction_parctl) {
u_sess->wlm_cxt->stroedproc_rp_reserve = t_thrd.wlm_cxt.parctl_state.rp_reserve;
u_sess->wlm_cxt->stroedproc_rp_release = t_thrd.wlm_cxt.parctl_state.rp_release;
u_sess->wlm_cxt->stroedproc_release = t_thrd.wlm_cxt.parctl_state.release;
}
/* Retain the parameters of the main statement */
if (!IsQidInvalid(&u_sess->wlm_cxt->wlm_params.qid)) {
rc = memcpy_s(&stroed_proc_qid, sizeof(Qid), &u_sess->wlm_cxt->wlm_params.qid, sizeof(Qid));
securec_check(rc, "\0", "\0");
}
stroed_proc_parctl_state_except = t_thrd.wlm_cxt.parctl_state.except;
stroed_proc_g_collect_info_status = t_thrd.wlm_cxt.collect_info->status;
stroed_proc_is_active_statements_reset = u_sess->wlm_cxt->is_active_statements_reset;
t_thrd.wlm_cxt.parctl_state.subquery = 1;
WLMInitQueryPlan(es->qd);
dywlm_client_manager(es->qd);
}
ExecutorRun(es->qd, ForwardScanDirection, count);
if (ENABLE_WORKLOAD_CONTROL && IS_PGXC_COORDINATOR && forced_control) {
t_thrd.wlm_cxt.parctl_state.except = 0;
if (g_instance.wlm_cxt->dynamic_workload_inited && (t_thrd.wlm_cxt.parctl_state.simple == 0)) {
dywlm_client_release(&t_thrd.wlm_cxt.parctl_state);
} else {
// only release resource pool count
if (IS_PGXC_COORDINATOR && !IsConnFromCoord() &&
(u_sess->wlm_cxt->parctl_state_exit || IsQueuedSubquery())) {
WLMReleaseGroupActiveStatement();
}
}
WLMSetCollectInfoStatus(WLM_STATUS_FINISHED);
t_thrd.wlm_cxt.parctl_state.subquery = 0;
t_thrd.wlm_cxt.parctl_state.except = stroed_proc_parctl_state_except;
t_thrd.wlm_cxt.collect_info->status = stroed_proc_g_collect_info_status;
u_sess->wlm_cxt->is_active_statements_reset = stroed_proc_is_active_statements_reset;
if (!IsQidInvalid(&stroed_proc_qid)) {
rc = memcpy_s(&u_sess->wlm_cxt->wlm_params.qid, sizeof(Qid), &stroed_proc_qid, sizeof(Qid));
securec_check(rc, "\0", "\0");
}
/* restore state condition if guc para is off since it contains unreleased count */
if (!u_sess->attr.attr_resource.enable_transaction_parctl &&
(u_sess->wlm_cxt->reserved_in_active_statements || u_sess->wlm_cxt->reserved_in_group_statements ||
u_sess->wlm_cxt->reserved_in_group_statements_simple)) {
t_thrd.wlm_cxt.parctl_state.rp_reserve = u_sess->wlm_cxt->stroedproc_rp_reserve;
t_thrd.wlm_cxt.parctl_state.rp_release = u_sess->wlm_cxt->stroedproc_rp_release;
t_thrd.wlm_cxt.parctl_state.release = u_sess->wlm_cxt->stroedproc_release;
}
}
/*
* If we requested run to completion OR there was no tuple returned,
* command must be complete.
*/
result = (count == 0L || 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->utilitystmt == NULL) {
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 param_li;
int i;
if (fcache->paramLI == NULL) {
param_li = (ParamListInfo)palloc(offsetof(ParamListInfoData, params) + nargs * sizeof(ParamExternData));
/* we have static list of params, so no hooks needed */
param_li->paramFetch = NULL;
param_li->paramFetchArg = NULL;
param_li->parserSetup = NULL;
param_li->parserSetupArg = NULL;
param_li->params_need_process = false;
param_li->numParams = nargs;
fcache->paramLI = param_li;
} else {
param_li = fcache->paramLI;
Assert(param_li->numParams == nargs);
}
for (i = 0; i < nargs; i++) {
ParamExternData* prm = &param_li->params[i];
prm->value = fcinfo->arg[i];
prm->isnull = fcinfo->argnull[i];
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 result_context)
{
Assert(slot != NULL);
Datum value;
MemoryContext old_context;
/*
* 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.
*/
old_context = MemoryContextSwitchTo(result_context);
if (fcache->returnsTuple) {
/* We must return the whole tuple as a Datum. */
fcinfo->isnull = false;
value = ExecFetchSlotTupleDatum(slot);
value = datumCopy(value, fcache->typbyval, fcache->typlen);
} 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.
*/
/* Get the Table Accessor Method*/
Assert(slot->tts_tupleDescriptor != NULL);
value = tableam_tslot_getattr(slot, 1, &(fcinfo->isnull));
if (!fcinfo->isnull)
value = datumCopy(value, fcache->typbyval, fcache->typlen);
}
MemoryContextSwitchTo(old_context);
return value;
}
static void auditExecSQLFunction(Oid fn_oid, SQLFunctionCache* func, AuditResult result)
{
char details[PGAUDIT_MAXLENGTH];
Assert(func != NULL);
if (fn_oid < FirstNormalObjectId)
return;
int ret = snprintf_s(details, sizeof(details), sizeof(details) - 1, "Execute SQL function(%s). ", func->fname);
securec_check_ss(ret, "", "");
audit_report(AUDIT_FUNCTION_EXEC, result, func->fname, details);
}
/*
* fmgr_sql: function call manager for SQL functions
*/
Datum fmgr_sql(PG_FUNCTION_ARGS)
{
SQLFunctionCachePtr fcache = NULL;
ErrorContextCallback sql_err_context;
MemoryContext old_context;
bool random_access = false;
bool lazy_eval_ok = false;
bool is_first = false;
bool pushed_snapshot = false;
execution_state* es = NULL;
TupleTableSlot* slot = NULL;
Datum result;
List* es_list = NIL;
ListCell* eslc = NULL;
bool old_running_in_fmgr = t_thrd.codegen_cxt.g_runningInFmgr;
t_thrd.codegen_cxt.g_runningInFmgr = true;
bool need_snapshot = !ActiveSnapshotSet();
#ifdef STREAMPLAN
bool outer_is_stream = false;
bool outer_is_stream_support = false;
if (IS_PGXC_COORDINATOR) {
outer_is_stream = u_sess->opt_cxt.is_stream;
outer_is_stream_support = u_sess->opt_cxt.is_stream_support;
u_sess->opt_cxt.is_stream = true;
u_sess->opt_cxt.is_stream_support = true;
}
#endif
/*
* Setup error traceback support for ereport()
*/
sql_err_context.callback = sql_exec_error_callback;
sql_err_context.arg = fcinfo->flinfo;
sql_err_context.previous = t_thrd.log_cxt.error_context_stack;
t_thrd.log_cxt.error_context_stack = &sql_err_context;
/* 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 == NULL || !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")));
random_access = rsi->allowedModes & SFRM_Materialize_Random;
lazy_eval_ok = !(rsi->allowedModes & SFRM_Materialize_Preferred);
} else {
random_access = false;
lazy_eval_ok = true;
}
if (need_snapshot) {
PushActiveSnapshot(GetTransactionSnapshot());
}
/*
* 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 != t_thrd.proc->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->flinfo, PG_GET_COLLATION(), lazy_eval_ok);
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.)
*/
old_context = MemoryContextSwitchTo(fcache->fcontext);
/*
* Find first unfinished query in function, and note whether it's the
* first query.
*/
es_list = fcache->func_state;
es = NULL;
is_first = true;
foreach (eslc, es_list) {
es = (execution_state*)lfirst(eslc);
while (es != NULL && es->status == F_EXEC_DONE) {
is_first = false;
es = es->next;
}
if (es != NULL)
break;
}
/*
* Convert params to appropriate format if starting a fresh execution. (If
* continuing execution, we can re-use prior params.)
*/
if (is_first && es != NULL && 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 == NULL)
fcache->tstore = tuplestore_begin_heap(random_access, false, u_sess->attr.attr_memory.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 != NULL) {
bool completed = false;
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 == NULL) {
eslc = lnext(eslc);
if (eslc == NULL)
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;
}
}
}
if (AUDIT_EXEC_ENABLED) {
auditExecSQLFunction(fcinfo->flinfo->fn_oid, fcache, AUDIT_OK);
}
/*
* The tuplestore now contains whatever row(s) we are supposed to return.
*/
if (fcache->returnsSet) {
ReturnSetInfo* rsi = (ReturnSetInfo*)fcinfo->resultinfo;
if (es != NULL) {
/*
* 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);
if (fcache->junkFilter == NULL) {
ereport(ERROR,
(errcode(ERRCODE_FETCH_DATA_FAILED),
errmsg("function returns VOID, failed to get junk filter's slot")));
}
slot = fcache->junkFilter->jf_resultSlot;
if (!tuplestore_gettupleslot(fcache->tstore, true, false, slot))
ereport(ERROR, (errcode(ERRCODE_FETCH_DATA_FAILED), errmsg("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, old_context);
/* 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 execQual will free it */
if (fcache->junkFilter != NULL)
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 != NULL) {
/* 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, old_context);
else {
fcinfo->isnull = true;
result = (Datum)0;
}
} else {
/* Should only get here for VOID functions */
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 (need_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 != NULL) {
es->status = F_EXEC_START;
es = es->next;
}
}
}
t_thrd.log_cxt.error_context_stack = sql_err_context.previous;
MemoryContextSwitchTo(old_context);
#ifdef STREAMPLAN
if (IS_PGXC_COORDINATOR) {
u_sess->opt_cxt.is_stream = outer_is_stream;
u_sess->opt_cxt.is_stream_support = outer_is_stream_support;
}
#endif
t_thrd.codegen_cxt.g_runningInFmgr = old_running_in_fmgr;
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 syntax_err_position;
/*
* 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
*/
syntax_err_position = geterrposition();
if (syntax_err_position > 0 && fcache->src != NULL) {
errposition(0);
internalerrposition(syntax_err_position);
internalerrquery(fcache->src);
}
if (AUDIT_EXEC_ENABLED) {
int e_level;
int sql_state;
getElevelAndSqlstate(&e_level, &sql_state);
if (e_level >= ERROR)
auditExecSQLFunction(flinfo->fn_oid, fcache, AUDIT_FAILED);
}
/*
* 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 != NULL) {
execution_state* es = NULL;
int query_num;
ListCell* lc = NULL;
es = NULL;
query_num = 1;
foreach (lc, fcache->func_state) {
es = (execution_state*)lfirst(lc);
while (es != NULL) {
if (es->qd != NULL) {
errcontext("SQL function \"%s\" statement %d", fcache->fname, query_num);
break;
}
es = es->next;
}
if (es != NULL)
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 = NULL;
ListCell* lc = NULL;
foreach (lc, fcache->func_state) {
es = (execution_state*)lfirst(lc);
while (es != NULL) {
/* 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 != NULL)
tuplestore_end(fcache->tstore);
fcache->tstore = NULL;
/* execUtils will deregister the callback... */
fcache->shutdown_reg = false;
}
/*
* check_sql_fn_retval() -- check return value of a list 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 here
* to be sure that the user is returning the type he claims. There are
* also a couple of strange-looking features to assist callers in dealing
* with allowed special cases, such as binary-compatible result types.
*
* For a polymorphic function the passed rettype must be the actual resolved
* output type of the function; we should never see a polymorphic pseudotype
* such as ANYELEMENT as rettype. (This means we can't check the type during
* function definition of a polymorphic function.)
*
* 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.
*
* If modifyTargetList isn't NULL, the function will modify the final
* statement's targetlist in two cases:
* (1) if the tlist returns values that are binary-coercible to the expected
* type rather than being exactly the expected type. RelabelType nodes will
* be inserted to make the result types match exactly.
* (2) if there are dropped columns in the declared result rowtype. NULL
* output columns will be inserted in the tlist to match them.
* (Obviously the caller must pass a parsetree that is okay to modify when
* using this flag.) Note that this flag does not affect whether the tlist is
* considered to be a legal match to the result type, only how we react to
* allowed not-exact-match cases. *modifyTargetList will be set true iff
* we had to make any "dangerous" changes that could modify the semantics of
* the statement. If it is set true, the caller should not use the modified
* statement, but for simplicity we apply the changes anyway.
*
* If junkFilter isn't NULL, then *junkFilter is set to a JunkFilter defined
* to convert the function's tuple result to the correct output tuple type.
* Exception: if the function is defined to return VOID then *junkFilter is
* set to NULL.
*/
bool check_sql_fn_retval(Oid func_id, Oid ret_type, List* query_tree_list, bool* modify_target_list, JunkFilter** junk_filter)
{
Query* parse = NULL;
List** tlist_ptr;
List* tlist = NIL;
int tlist_len;
char fn_type;
Oid res_type;
ListCell* lc = NULL;
AssertArg(!IsPolymorphicType(ret_type));
if (modify_target_list != NULL)
*modify_target_list = false; /* initialize for no change */
if (junk_filter != NULL)
*junk_filter = NULL; /* initialize in case of VOID result */
/*
* Find the last canSetTag query in the list. This isn't necessarily the
* last parsetree, because rule rewriting can insert queries after what
* the user wrote.
*/
parse = NULL;
foreach (lc, query_tree_list) {
Query* q = (Query*)lfirst(lc);
if (q->canSetTag)
parse = q;
}
/*
* 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 != NULL && parse->commandType == CMD_SELECT && parse->utilityStmt == NULL) {
tlist_ptr = &parse->targetList;
tlist = parse->targetList;
} else if (parse != NULL &&
(parse->commandType == CMD_INSERT || parse->commandType == CMD_UPDATE ||
parse->commandType == CMD_DELETE) &&
parse->returningList) {
tlist_ptr = &parse->returningList;
tlist = parse->returningList;
} else {
/* Empty function body, or last statement is a utility command */
if (ret_type != VOIDOID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s", format_type_be(ret_type)),
errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE RETURNING.")));
return false;
}
/*
* OK, check that the targetlist returns something matching the declared
* type. (We used to insist that the declared type not be VOID in this
* case, but that makes it hard to write a void function that exits after
* calling another void function. Instead, we insist that the tlist
* return void ... so void is treated as if it were a scalar type below.)
*/
/*
* Count the non-junk entries in the result targetlist.
*/
tlist_len = ExecCleanTargetListLength(tlist);
fn_type = get_typtype(ret_type);
if (fn_type == TYPTYPE_BASE || fn_type == TYPTYPE_DOMAIN || fn_type == TYPTYPE_ENUM ||
fn_type == TYPTYPE_RANGE || ret_type == VOIDOID) {
/*
* For scalar-type returns, the target list must have exactly one
* non-junk entry, and its type must agree with what the user
* declared; except we allow binary-compatible types too.
*/
TargetEntry* tle = NULL;
if (tlist_len != 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s", format_type_be(ret_type)),
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);
res_type = exprType((Node*)tle->expr);
if (!IsBinaryCoercible(res_type, ret_type))
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s", format_type_be(ret_type)),
errdetail("Actual return type is %s.", format_type_be(res_type))));
if (modify_target_list != NULL && res_type != ret_type) {
tle->expr = (Expr*)makeRelabelType(tle->expr, ret_type, -1, get_typcollation(ret_type), COERCE_DONTCARE);
/* Relabel is dangerous if TLE is a sort/group or setop column */
if (tle->ressortgroupref != 0 || parse->setOperations)
*modify_target_list = true;
}
/* Set up junk filter if needed */
if (junk_filter != NULL)
*junk_filter = ExecInitJunkFilter(tlist, false, NULL);
} else if (fn_type == TYPTYPE_COMPOSITE || ret_type == RECORDOID) {
/* Returns a rowtype */
TupleDesc tup_desc;
int tup_natts; /* physical number of columns in tuple */
int tup_log_cols; /* # of nondeleted columns in tuple */
int col_index; /* physical column index */
List* new_tlist = NIL; /* new non-junk tlist entries */
List* junk_attrs = NIL; /* new junk tlist entries */
/*
* If the target list is of length 1, and the type of the varnode in
* the target list matches the declared return type, this is okay.
* This can happen, for example, where the body of the function is
* 'SELECT func2()', where func2 has the same composite return type as
* the function that's calling it.
*
* XXX Note that if rettype is RECORD, the IsBinaryCoercible check
* will succeed for any composite restype. 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 (tlist_len == 1) {
TargetEntry* tle = (TargetEntry*)linitial(tlist);
Assert(!tle->resjunk);
res_type = exprType((Node*)tle->expr);
if (IsBinaryCoercible(res_type, ret_type)) {
if (modify_target_list != NULL && res_type != ret_type) {
tle->expr =
(Expr*)makeRelabelType(tle->expr, ret_type, -1, get_typcollation(ret_type), COERCE_DONTCARE);
/* Relabel is dangerous if sort/group or setop column */
if (tle->ressortgroupref != 0 || parse->setOperations)
*modify_target_list = true;
}
/* Set up junk filter if needed */
if (junk_filter != NULL)
*junk_filter = ExecInitJunkFilter(tlist, false, NULL);
return false; /* NOT returning whole tuple */
}
}
/* Is the rowtype fixed, or determined only at runtime? */
if (get_func_result_type(func_id, NULL, &tup_desc) != TYPEFUNC_COMPOSITE) {
/*
* Assume we are returning the whole tuple. Crosschecking against
* what the caller expects will happen at runtime.
*/
if (junk_filter != NULL)
*junk_filter = ExecInitJunkFilter(tlist, false, NULL);
return true;
}
Assert(tup_desc);
/*
* Verify that the targetlist matches the return tuple type. We scan
* the non-deleted attributes to ensure that they match the datatypes
* of the non-resjunk columns. For deleted attributes, insert NULL
* result columns if the caller asked for that.
*/
tup_natts = tup_desc->natts;
tup_log_cols = 0; /* we'll count nondeleted cols as we go */
col_index = 0;
new_tlist = NIL; /* these are only used if modifyTargetList */
junk_attrs = NIL;
foreach (lc, tlist) {
TargetEntry* tle = (TargetEntry*)lfirst(lc);
Form_pg_attribute attr;
Oid tle_type;
Oid att_type;
if (tle->resjunk) {
if (modify_target_list != NULL)
junk_attrs = lappend(junk_attrs, tle);
continue;
}
do {
col_index++;
if (col_index > tup_natts)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s", format_type_be(ret_type)),
errdetail("Final statement returns too many columns.")));
attr = tup_desc->attrs[col_index - 1];
if (attr->attisdropped && modify_target_list) {
Expr* null_expr = NULL;
/* 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 */);
new_tlist = lappend(new_tlist, makeTargetEntry(null_expr, col_index, NULL, false));
/* NULL insertion is dangerous in a setop */
if (parse->setOperations)
*modify_target_list = true;
}
} while (attr->attisdropped);
tup_log_cols++;
tle_type = exprType((Node*)tle->expr);
att_type = attr->atttypid;
if (!IsBinaryCoercible(tle_type, att_type))
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s", format_type_be(ret_type)),
errdetail("Final statement returns %s instead of %s at column %d.",
format_type_be(tle_type),
format_type_be(att_type),
tup_log_cols)));
if (modify_target_list != NULL) {
if (tle_type != att_type) {
tle->expr =
(Expr*)makeRelabelType(tle->expr, att_type, -1, get_typcollation(att_type), COERCE_DONTCARE);
/* Relabel is dangerous if sort/group or setop column */
if (tle->ressortgroupref != 0 || parse->setOperations)
*modify_target_list = true;
}
tle->resno = col_index;
new_tlist = lappend(new_tlist, tle);
}
}
/* remaining columns in tupdesc had better all be dropped */
for (col_index++; col_index <= tup_natts; col_index++) {
if (!tup_desc->attrs[col_index - 1]->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s", format_type_be(ret_type)),
errdetail("Final statement returns too few columns.")));
if (modify_target_list != NULL) {
Expr* null_expr = NULL;
/* 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 */);
new_tlist = lappend(new_tlist, makeTargetEntry(null_expr, col_index, NULL, false));
/* NULL insertion is dangerous in a setop */
if (parse->setOperations)
*modify_target_list = true;
}
}
if (modify_target_list != NULL) {
/* ensure resjunk columns are numbered correctly */
foreach (lc, junk_attrs) {
TargetEntry* tle = (TargetEntry*)lfirst(lc);
tle->resno = col_index++;
}
/* replace the tlist with the modified one */
*tlist_ptr = list_concat(new_tlist, junk_attrs);
}
/* Set up junk filter if needed */
if (junk_filter != NULL)
*junk_filter = ExecInitJunkFilterConversion(tlist, CreateTupleDescCopy(tup_desc), NULL);
/* Report that we are returning entire tuple result */
return true;
} else
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type %s is not supported for SQL functions with ID %u.",
format_type_be(ret_type),
func_id)));
return false;
}
/*
* 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;
self->pub.tmpContext = NULL;
/* private fields will be set by postquel_start */
return (DestReceiver*)self;
}
/*
* sqlfunction_startup --- executor startup
*/
static void sqlfunction_startup(DestReceiver* self, int operation, TupleDesc type_info)
{
/* no-op */
}
/*
* sqlfunction_receive --- receive one tuple
*/
static void sqlfunction_receive(TupleTableSlot* slot, DestReceiver* self)
{
DR_sqlfunction* my_state = (DR_sqlfunction*)self;
/* Filter tuple as needed */
slot = ExecFilterJunk(my_state->filter, slot);
/* Store the filtered tuple into the tuplestore */
tuplestore_puttupleslot(my_state->tstore, slot);
}
/*
* sqlfunction_shutdown --- executor end
*/
static void sqlfunction_shutdown(DestReceiver* self)
{
/* no-op */
}
/*
* sqlfunction_destroy --- release DestReceiver object
*/
static void sqlfunction_destroy(DestReceiver* self)
{
pfree_ext(self);
}