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postgresql/src/backend/executor/spi.c

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/*-------------------------------------------------------------------------
*
* spi.c
* Server Programming Interface
*
* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/executor/spi.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/printtup.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/heap.h"
#include "catalog/pg_type.h"
#include "commands/trigger.h"
#include "executor/executor.h"
#include "executor/spi_priv.h"
#include "tcop/pquery.h"
#include "tcop/utility.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/typcache.h"
uint32 SPI_processed = 0;
Oid SPI_lastoid = InvalidOid;
SPITupleTable *SPI_tuptable = NULL;
int SPI_result;
static _SPI_connection *_SPI_stack = NULL;
static _SPI_connection *_SPI_current = NULL;
static int _SPI_stack_depth = 0; /* allocated size of _SPI_stack */
static int _SPI_connected = -1;
static int _SPI_curid = -1;
static Portal SPI_cursor_open_internal(const char *name, SPIPlanPtr plan,
ParamListInfo paramLI, bool read_only);
static void _SPI_prepare_plan(const char *src, SPIPlanPtr plan,
ParamListInfo boundParams);
static int _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
Snapshot snapshot, Snapshot crosscheck_snapshot,
bool read_only, bool fire_triggers, long tcount);
static ParamListInfo _SPI_convert_params(int nargs, Oid *argtypes,
Datum *Values, const char *Nulls,
int pflags);
static int _SPI_pquery(QueryDesc *queryDesc, bool fire_triggers, long tcount);
static void _SPI_error_callback(void *arg);
static void _SPI_cursor_operation(Portal portal,
FetchDirection direction, long count,
DestReceiver *dest);
static SPIPlanPtr _SPI_copy_plan(SPIPlanPtr plan, MemoryContext parentcxt);
static SPIPlanPtr _SPI_save_plan(SPIPlanPtr plan);
static int _SPI_begin_call(bool execmem);
static int _SPI_end_call(bool procmem);
static MemoryContext _SPI_execmem(void);
static MemoryContext _SPI_procmem(void);
static bool _SPI_checktuples(void);
/* =================== interface functions =================== */
int
SPI_connect(void)
{
int newdepth;
/*
* When procedure called by Executor _SPI_curid expected to be equal to
* _SPI_connected
*/
if (_SPI_curid != _SPI_connected)
return SPI_ERROR_CONNECT;
if (_SPI_stack == NULL)
{
if (_SPI_connected != -1 || _SPI_stack_depth != 0)
elog(ERROR, "SPI stack corrupted");
newdepth = 16;
_SPI_stack = (_SPI_connection *)
MemoryContextAlloc(TopTransactionContext,
newdepth * sizeof(_SPI_connection));
_SPI_stack_depth = newdepth;
}
else
{
if (_SPI_stack_depth <= 0 || _SPI_stack_depth <= _SPI_connected)
elog(ERROR, "SPI stack corrupted");
if (_SPI_stack_depth == _SPI_connected + 1)
{
newdepth = _SPI_stack_depth * 2;
_SPI_stack = (_SPI_connection *)
repalloc(_SPI_stack,
newdepth * sizeof(_SPI_connection));
_SPI_stack_depth = newdepth;
}
}
/*
* We're entering procedure where _SPI_curid == _SPI_connected - 1
*/
_SPI_connected++;
Assert(_SPI_connected >= 0 && _SPI_connected < _SPI_stack_depth);
_SPI_current = &(_SPI_stack[_SPI_connected]);
_SPI_current->processed = 0;
_SPI_current->lastoid = InvalidOid;
_SPI_current->tuptable = NULL;
_SPI_current->procCxt = NULL; /* in case we fail to create 'em */
_SPI_current->execCxt = NULL;
_SPI_current->connectSubid = GetCurrentSubTransactionId();
/*
* Create memory contexts for this procedure
*
* XXX it would be better to use PortalContext as the parent context, but
* we may not be inside a portal (consider deferred-trigger execution).
* Perhaps CurTransactionContext would do? For now it doesn't matter
* because we clean up explicitly in AtEOSubXact_SPI().
*/
_SPI_current->procCxt = AllocSetContextCreate(TopTransactionContext,
"SPI Proc",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
_SPI_current->execCxt = AllocSetContextCreate(TopTransactionContext,
"SPI Exec",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/* ... and switch to procedure's context */
_SPI_current->savedcxt = MemoryContextSwitchTo(_SPI_current->procCxt);
return SPI_OK_CONNECT;
}
int
SPI_finish(void)
{
int res;
res = _SPI_begin_call(false); /* live in procedure memory */
if (res < 0)
return res;
/* Restore memory context as it was before procedure call */
MemoryContextSwitchTo(_SPI_current->savedcxt);
/* Release memory used in procedure call */
MemoryContextDelete(_SPI_current->execCxt);
_SPI_current->execCxt = NULL;
MemoryContextDelete(_SPI_current->procCxt);
_SPI_current->procCxt = NULL;
/*
* Reset result variables, especially SPI_tuptable which is probably
* pointing at a just-deleted tuptable
*/
SPI_processed = 0;
SPI_lastoid = InvalidOid;
SPI_tuptable = NULL;
/*
* After _SPI_begin_call _SPI_connected == _SPI_curid. Now we are closing
* connection to SPI and returning to upper Executor and so _SPI_connected
* must be equal to _SPI_curid.
*/
_SPI_connected--;
_SPI_curid--;
if (_SPI_connected == -1)
_SPI_current = NULL;
else
_SPI_current = &(_SPI_stack[_SPI_connected]);
return SPI_OK_FINISH;
}
/*
* Clean up SPI state at transaction commit or abort.
*/
void
AtEOXact_SPI(bool isCommit)
{
/*
* Note that memory contexts belonging to SPI stack entries will be freed
* automatically, so we can ignore them here. We just need to restore our
* static variables to initial state.
*/
if (isCommit && _SPI_connected != -1)
ereport(WARNING,
(errcode(ERRCODE_WARNING),
errmsg("transaction left non-empty SPI stack"),
errhint("Check for missing \"SPI_finish\" calls.")));
_SPI_current = _SPI_stack = NULL;
_SPI_stack_depth = 0;
_SPI_connected = _SPI_curid = -1;
SPI_processed = 0;
SPI_lastoid = InvalidOid;
SPI_tuptable = NULL;
}
/*
* Clean up SPI state at subtransaction commit or abort.
*
* During commit, there shouldn't be any unclosed entries remaining from
* the current subtransaction; we emit a warning if any are found.
*/
void
AtEOSubXact_SPI(bool isCommit, SubTransactionId mySubid)
{
bool found = false;
while (_SPI_connected >= 0)
{
_SPI_connection *connection = &(_SPI_stack[_SPI_connected]);
if (connection->connectSubid != mySubid)
break; /* couldn't be any underneath it either */
found = true;
/*
* Release procedure memory explicitly (see note in SPI_connect)
*/
if (connection->execCxt)
{
MemoryContextDelete(connection->execCxt);
connection->execCxt = NULL;
}
if (connection->procCxt)
{
MemoryContextDelete(connection->procCxt);
connection->procCxt = NULL;
}
/*
* Pop the stack entry and reset global variables. Unlike
* SPI_finish(), we don't risk switching to memory contexts that might
* be already gone.
*/
_SPI_connected--;
_SPI_curid = _SPI_connected;
if (_SPI_connected == -1)
_SPI_current = NULL;
else
_SPI_current = &(_SPI_stack[_SPI_connected]);
SPI_processed = 0;
SPI_lastoid = InvalidOid;
SPI_tuptable = NULL;
}
if (found && isCommit)
ereport(WARNING,
(errcode(ERRCODE_WARNING),
errmsg("subtransaction left non-empty SPI stack"),
errhint("Check for missing \"SPI_finish\" calls.")));
/*
* If we are aborting a subtransaction and there is an open SPI context
* surrounding the subxact, clean up to prevent memory leakage.
*/
if (_SPI_current && !isCommit)
{
/* free Executor memory the same as _SPI_end_call would do */
MemoryContextResetAndDeleteChildren(_SPI_current->execCxt);
/* throw away any partially created tuple-table */
SPI_freetuptable(_SPI_current->tuptable);
_SPI_current->tuptable = NULL;
}
}
/* Pushes SPI stack to allow recursive SPI calls */
void
SPI_push(void)
{
_SPI_curid++;
}
/* Pops SPI stack to allow recursive SPI calls */
void
SPI_pop(void)
{
_SPI_curid--;
}
/* Conditional push: push only if we're inside a SPI procedure */
bool
SPI_push_conditional(void)
{
bool pushed = (_SPI_curid != _SPI_connected);
if (pushed)
{
_SPI_curid++;
/* We should now be in a state where SPI_connect would succeed */
Assert(_SPI_curid == _SPI_connected);
}
return pushed;
}
/* Conditional pop: pop only if SPI_push_conditional pushed */
void
SPI_pop_conditional(bool pushed)
{
/* We should be in a state where SPI_connect would succeed */
Assert(_SPI_curid == _SPI_connected);
if (pushed)
_SPI_curid--;
}
/* Restore state of SPI stack after aborting a subtransaction */
void
SPI_restore_connection(void)
{
Assert(_SPI_connected >= 0);
_SPI_curid = _SPI_connected - 1;
}
/* Parse, plan, and execute a query string */
int
SPI_execute(const char *src, bool read_only, long tcount)
{
_SPI_plan plan;
int res;
if (src == NULL || tcount < 0)
return SPI_ERROR_ARGUMENT;
res = _SPI_begin_call(true);
if (res < 0)
return res;
memset(&plan, 0, sizeof(_SPI_plan));
plan.magic = _SPI_PLAN_MAGIC;
plan.cursor_options = 0;
_SPI_prepare_plan(src, &plan, NULL);
res = _SPI_execute_plan(&plan, NULL,
InvalidSnapshot, InvalidSnapshot,
read_only, true, tcount);
_SPI_end_call(true);
return res;
}
/* Obsolete version of SPI_execute */
int
SPI_exec(const char *src, long tcount)
{
return SPI_execute(src, false, tcount);
}
/* Execute a previously prepared plan */
int
SPI_execute_plan(SPIPlanPtr plan, Datum *Values, const char *Nulls,
bool read_only, long tcount)
{
int res;
if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC || tcount < 0)
return SPI_ERROR_ARGUMENT;
if (plan->nargs > 0 && Values == NULL)
return SPI_ERROR_PARAM;
res = _SPI_begin_call(true);
if (res < 0)
return res;
res = _SPI_execute_plan(plan,
_SPI_convert_params(plan->nargs, plan->argtypes,
Values, Nulls,
0),
InvalidSnapshot, InvalidSnapshot,
read_only, true, tcount);
_SPI_end_call(true);
return res;
}
/* Obsolete version of SPI_execute_plan */
int
SPI_execp(SPIPlanPtr plan, Datum *Values, const char *Nulls, long tcount)
{
return SPI_execute_plan(plan, Values, Nulls, false, tcount);
}
/* Execute a previously prepared plan */
int
SPI_execute_plan_with_paramlist(SPIPlanPtr plan, ParamListInfo params,
bool read_only, long tcount)
{
int res;
if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC || tcount < 0)
return SPI_ERROR_ARGUMENT;
res = _SPI_begin_call(true);
if (res < 0)
return res;
res = _SPI_execute_plan(plan, params,
InvalidSnapshot, InvalidSnapshot,
read_only, true, tcount);
_SPI_end_call(true);
return res;
}
/*
* SPI_execute_snapshot -- identical to SPI_execute_plan, except that we allow
* the caller to specify exactly which snapshots to use, which will be
* registered here. Also, the caller may specify that AFTER triggers should be
* queued as part of the outer query rather than being fired immediately at the
* end of the command.
*
* This is currently not documented in spi.sgml because it is only intended
* for use by RI triggers.
*
* Passing snapshot == InvalidSnapshot will select the normal behavior of
* fetching a new snapshot for each query.
*/
int
SPI_execute_snapshot(SPIPlanPtr plan,
Datum *Values, const char *Nulls,
Snapshot snapshot, Snapshot crosscheck_snapshot,
bool read_only, bool fire_triggers, long tcount)
{
int res;
if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC || tcount < 0)
return SPI_ERROR_ARGUMENT;
if (plan->nargs > 0 && Values == NULL)
return SPI_ERROR_PARAM;
res = _SPI_begin_call(true);
if (res < 0)
return res;
res = _SPI_execute_plan(plan,
_SPI_convert_params(plan->nargs, plan->argtypes,
Values, Nulls,
0),
snapshot, crosscheck_snapshot,
read_only, fire_triggers, tcount);
_SPI_end_call(true);
return res;
}
/*
* SPI_execute_with_args -- plan and execute a query with supplied arguments
*
* This is functionally comparable to SPI_prepare followed by
* SPI_execute_plan, except that since we know the plan will be used only
* once, we can tell the planner to rely on the parameter values as constants.
* This eliminates potential performance disadvantages compared to
* inserting the parameter values directly into the query text.
*/
int
SPI_execute_with_args(const char *src,
int nargs, Oid *argtypes,
Datum *Values, const char *Nulls,
bool read_only, long tcount)
{
int res;
_SPI_plan plan;
ParamListInfo paramLI;
if (src == NULL || nargs < 0 || tcount < 0)
return SPI_ERROR_ARGUMENT;
if (nargs > 0 && (argtypes == NULL || Values == NULL))
return SPI_ERROR_PARAM;
res = _SPI_begin_call(true);
if (res < 0)
return res;
memset(&plan, 0, sizeof(_SPI_plan));
plan.magic = _SPI_PLAN_MAGIC;
plan.cursor_options = 0;
plan.nargs = nargs;
plan.argtypes = argtypes;
plan.parserSetup = NULL;
plan.parserSetupArg = NULL;
paramLI = _SPI_convert_params(nargs, argtypes,
Values, Nulls,
PARAM_FLAG_CONST);
_SPI_prepare_plan(src, &plan, paramLI);
/* We don't need to copy the plan since it will be thrown away anyway */
res = _SPI_execute_plan(&plan, paramLI,
InvalidSnapshot, InvalidSnapshot,
read_only, true, tcount);
_SPI_end_call(true);
return res;
}
SPIPlanPtr
SPI_prepare(const char *src, int nargs, Oid *argtypes)
{
return SPI_prepare_cursor(src, nargs, argtypes, 0);
}
SPIPlanPtr
SPI_prepare_cursor(const char *src, int nargs, Oid *argtypes,
int cursorOptions)
{
_SPI_plan plan;
SPIPlanPtr result;
if (src == NULL || nargs < 0 || (nargs > 0 && argtypes == NULL))
{
SPI_result = SPI_ERROR_ARGUMENT;
return NULL;
}
SPI_result = _SPI_begin_call(true);
if (SPI_result < 0)
return NULL;
memset(&plan, 0, sizeof(_SPI_plan));
plan.magic = _SPI_PLAN_MAGIC;
plan.cursor_options = cursorOptions;
plan.nargs = nargs;
plan.argtypes = argtypes;
plan.parserSetup = NULL;
plan.parserSetupArg = NULL;
_SPI_prepare_plan(src, &plan, NULL);
/* copy plan to procedure context */
result = _SPI_copy_plan(&plan, _SPI_current->procCxt);
_SPI_end_call(true);
return result;
}
SPIPlanPtr
SPI_prepare_params(const char *src,
ParserSetupHook parserSetup,
void *parserSetupArg,
int cursorOptions)
{
_SPI_plan plan;
SPIPlanPtr result;
if (src == NULL)
{
SPI_result = SPI_ERROR_ARGUMENT;
return NULL;
}
SPI_result = _SPI_begin_call(true);
if (SPI_result < 0)
return NULL;
memset(&plan, 0, sizeof(_SPI_plan));
plan.magic = _SPI_PLAN_MAGIC;
plan.cursor_options = cursorOptions;
plan.nargs = 0;
plan.argtypes = NULL;
plan.parserSetup = parserSetup;
plan.parserSetupArg = parserSetupArg;
_SPI_prepare_plan(src, &plan, NULL);
/* copy plan to procedure context */
result = _SPI_copy_plan(&plan, _SPI_current->procCxt);
_SPI_end_call(true);
return result;
}
SPIPlanPtr
SPI_saveplan(SPIPlanPtr plan)
{
SPIPlanPtr newplan;
/* We don't currently support copying an already-saved plan */
if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC || plan->saved)
{
SPI_result = SPI_ERROR_ARGUMENT;
return NULL;
}
SPI_result = _SPI_begin_call(false); /* don't change context */
if (SPI_result < 0)
return NULL;
newplan = _SPI_save_plan(plan);
_SPI_curid--;
SPI_result = 0;
return newplan;
}
int
SPI_freeplan(SPIPlanPtr plan)
{
if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC)
return SPI_ERROR_ARGUMENT;
/* If plancache.c owns the plancache entries, we must release them */
if (plan->saved)
{
ListCell *lc;
foreach(lc, plan->plancache_list)
{
CachedPlanSource *plansource = (CachedPlanSource *) lfirst(lc);
DropCachedPlan(plansource);
}
}
/* Now get rid of the _SPI_plan and subsidiary data in its plancxt */
MemoryContextDelete(plan->plancxt);
return 0;
}
HeapTuple
SPI_copytuple(HeapTuple tuple)
{
MemoryContext oldcxt = NULL;
HeapTuple ctuple;
if (tuple == NULL)
{
SPI_result = SPI_ERROR_ARGUMENT;
return NULL;
}
if (_SPI_curid + 1 == _SPI_connected) /* connected */
{
if (_SPI_current != &(_SPI_stack[_SPI_curid + 1]))
elog(ERROR, "SPI stack corrupted");
oldcxt = MemoryContextSwitchTo(_SPI_current->savedcxt);
}
ctuple = heap_copytuple(tuple);
if (oldcxt)
MemoryContextSwitchTo(oldcxt);
return ctuple;
}
HeapTupleHeader
SPI_returntuple(HeapTuple tuple, TupleDesc tupdesc)
{
MemoryContext oldcxt = NULL;
HeapTupleHeader dtup;
if (tuple == NULL || tupdesc == NULL)
{
SPI_result = SPI_ERROR_ARGUMENT;
return NULL;
}
/* For RECORD results, make sure a typmod has been assigned */
if (tupdesc->tdtypeid == RECORDOID &&
tupdesc->tdtypmod < 0)
assign_record_type_typmod(tupdesc);
if (_SPI_curid + 1 == _SPI_connected) /* connected */
{
if (_SPI_current != &(_SPI_stack[_SPI_curid + 1]))
elog(ERROR, "SPI stack corrupted");
oldcxt = MemoryContextSwitchTo(_SPI_current->savedcxt);
}
dtup = (HeapTupleHeader) palloc(tuple->t_len);
memcpy((char *) dtup, (char *) tuple->t_data, tuple->t_len);
HeapTupleHeaderSetDatumLength(dtup, tuple->t_len);
HeapTupleHeaderSetTypeId(dtup, tupdesc->tdtypeid);
HeapTupleHeaderSetTypMod(dtup, tupdesc->tdtypmod);
if (oldcxt)
MemoryContextSwitchTo(oldcxt);
return dtup;
}
HeapTuple
SPI_modifytuple(Relation rel, HeapTuple tuple, int natts, int *attnum,
Datum *Values, const char *Nulls)
{
MemoryContext oldcxt = NULL;
HeapTuple mtuple;
int numberOfAttributes;
Datum *v;
bool *n;
int i;
if (rel == NULL || tuple == NULL || natts < 0 || attnum == NULL || Values == NULL)
{
SPI_result = SPI_ERROR_ARGUMENT;
return NULL;
}
if (_SPI_curid + 1 == _SPI_connected) /* connected */
{
if (_SPI_current != &(_SPI_stack[_SPI_curid + 1]))
elog(ERROR, "SPI stack corrupted");
oldcxt = MemoryContextSwitchTo(_SPI_current->savedcxt);
}
SPI_result = 0;
numberOfAttributes = rel->rd_att->natts;
v = (Datum *) palloc(numberOfAttributes * sizeof(Datum));
n = (bool *) palloc(numberOfAttributes * sizeof(bool));
/* fetch old values and nulls */
heap_deform_tuple(tuple, rel->rd_att, v, n);
/* replace values and nulls */
for (i = 0; i < natts; i++)
{
if (attnum[i] <= 0 || attnum[i] > numberOfAttributes)
break;
v[attnum[i] - 1] = Values[i];
n[attnum[i] - 1] = (Nulls && Nulls[i] == 'n') ? true : false;
}
if (i == natts) /* no errors in *attnum */
{
mtuple = heap_form_tuple(rel->rd_att, v, n);
/*
* copy the identification info of the old tuple: t_ctid, t_self, and
* OID (if any)
*/
mtuple->t_data->t_ctid = tuple->t_data->t_ctid;
mtuple->t_self = tuple->t_self;
mtuple->t_tableOid = tuple->t_tableOid;
if (rel->rd_att->tdhasoid)
HeapTupleSetOid(mtuple, HeapTupleGetOid(tuple));
}
else
{
mtuple = NULL;
SPI_result = SPI_ERROR_NOATTRIBUTE;
}
pfree(v);
pfree(n);
if (oldcxt)
MemoryContextSwitchTo(oldcxt);
return mtuple;
}
int
SPI_fnumber(TupleDesc tupdesc, const char *fname)
{
int res;
Form_pg_attribute sysatt;
for (res = 0; res < tupdesc->natts; res++)
{
if (namestrcmp(&tupdesc->attrs[res]->attname, fname) == 0)
return res + 1;
}
sysatt = SystemAttributeByName(fname, true /* "oid" will be accepted */ );
if (sysatt != NULL)
return sysatt->attnum;
/* SPI_ERROR_NOATTRIBUTE is different from all sys column numbers */
return SPI_ERROR_NOATTRIBUTE;
}
char *
SPI_fname(TupleDesc tupdesc, int fnumber)
{
Form_pg_attribute att;
SPI_result = 0;
if (fnumber > tupdesc->natts || fnumber == 0 ||
fnumber <= FirstLowInvalidHeapAttributeNumber)
{
SPI_result = SPI_ERROR_NOATTRIBUTE;
return NULL;
}
if (fnumber > 0)
att = tupdesc->attrs[fnumber - 1];
else
att = SystemAttributeDefinition(fnumber, true);
return pstrdup(NameStr(att->attname));
}
char *
SPI_getvalue(HeapTuple tuple, TupleDesc tupdesc, int fnumber)
{
char *result;
Datum origval,
val;
bool isnull;
Oid typoid,
foutoid;
bool typisvarlena;
SPI_result = 0;
if (fnumber > tupdesc->natts || fnumber == 0 ||
fnumber <= FirstLowInvalidHeapAttributeNumber)
{
SPI_result = SPI_ERROR_NOATTRIBUTE;
return NULL;
}
origval = heap_getattr(tuple, fnumber, tupdesc, &isnull);
if (isnull)
return NULL;
if (fnumber > 0)
typoid = tupdesc->attrs[fnumber - 1]->atttypid;
else
typoid = (SystemAttributeDefinition(fnumber, true))->atttypid;
getTypeOutputInfo(typoid, &foutoid, &typisvarlena);
/*
* If we have a toasted datum, forcibly detoast it here to avoid memory
* leakage inside the type's output routine.
*/
if (typisvarlena)
val = PointerGetDatum(PG_DETOAST_DATUM(origval));
else
val = origval;
result = OidOutputFunctionCall(foutoid, val);
/* Clean up detoasted copy, if any */
if (val != origval)
pfree(DatumGetPointer(val));
return result;
}
Datum
SPI_getbinval(HeapTuple tuple, TupleDesc tupdesc, int fnumber, bool *isnull)
{
SPI_result = 0;
if (fnumber > tupdesc->natts || fnumber == 0 ||
fnumber <= FirstLowInvalidHeapAttributeNumber)
{
SPI_result = SPI_ERROR_NOATTRIBUTE;
*isnull = true;
return (Datum) NULL;
}
return heap_getattr(tuple, fnumber, tupdesc, isnull);
}
char *
SPI_gettype(TupleDesc tupdesc, int fnumber)
{
Oid typoid;
HeapTuple typeTuple;
char *result;
SPI_result = 0;
if (fnumber > tupdesc->natts || fnumber == 0 ||
fnumber <= FirstLowInvalidHeapAttributeNumber)
{
SPI_result = SPI_ERROR_NOATTRIBUTE;
return NULL;
}
if (fnumber > 0)
typoid = tupdesc->attrs[fnumber - 1]->atttypid;
else
typoid = (SystemAttributeDefinition(fnumber, true))->atttypid;
typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typoid));
if (!HeapTupleIsValid(typeTuple))
{
SPI_result = SPI_ERROR_TYPUNKNOWN;
return NULL;
}
result = pstrdup(NameStr(((Form_pg_type) GETSTRUCT(typeTuple))->typname));
ReleaseSysCache(typeTuple);
return result;
}
Oid
SPI_gettypeid(TupleDesc tupdesc, int fnumber)
{
SPI_result = 0;
if (fnumber > tupdesc->natts || fnumber == 0 ||
fnumber <= FirstLowInvalidHeapAttributeNumber)
{
SPI_result = SPI_ERROR_NOATTRIBUTE;
return InvalidOid;
}
if (fnumber > 0)
return tupdesc->attrs[fnumber - 1]->atttypid;
else
return (SystemAttributeDefinition(fnumber, true))->atttypid;
}
char *
SPI_getrelname(Relation rel)
{
return pstrdup(RelationGetRelationName(rel));
}
char *
SPI_getnspname(Relation rel)
{
return get_namespace_name(RelationGetNamespace(rel));
}
void *
SPI_palloc(Size size)
{
MemoryContext oldcxt = NULL;
void *pointer;
if (_SPI_curid + 1 == _SPI_connected) /* connected */
{
if (_SPI_current != &(_SPI_stack[_SPI_curid + 1]))
elog(ERROR, "SPI stack corrupted");
oldcxt = MemoryContextSwitchTo(_SPI_current->savedcxt);
}
pointer = palloc(size);
if (oldcxt)
MemoryContextSwitchTo(oldcxt);
return pointer;
}
void *
SPI_repalloc(void *pointer, Size size)
{
/* No longer need to worry which context chunk was in... */
return repalloc(pointer, size);
}
void
SPI_pfree(void *pointer)
{
/* No longer need to worry which context chunk was in... */
pfree(pointer);
}
void
SPI_freetuple(HeapTuple tuple)
{
/* No longer need to worry which context tuple was in... */
heap_freetuple(tuple);
}
void
SPI_freetuptable(SPITupleTable *tuptable)
{
if (tuptable != NULL)
MemoryContextDelete(tuptable->tuptabcxt);
}
/*
* SPI_cursor_open()
*
* Open a prepared SPI plan as a portal
*/
Portal
SPI_cursor_open(const char *name, SPIPlanPtr plan,
Datum *Values, const char *Nulls,
bool read_only)
{
Portal portal;
ParamListInfo paramLI;
/* build transient ParamListInfo in caller's context */
paramLI = _SPI_convert_params(plan->nargs, plan->argtypes,
Values, Nulls,
0);
portal = SPI_cursor_open_internal(name, plan, paramLI, read_only);
/* done with the transient ParamListInfo */
if (paramLI)
pfree(paramLI);
return portal;
}
/*
* SPI_cursor_open_with_args()
*
* Parse and plan a query and open it as a portal. Like SPI_execute_with_args,
* we can tell the planner to rely on the parameter values as constants,
* because the plan will only be used once.
*/
Portal
SPI_cursor_open_with_args(const char *name,
const char *src,
int nargs, Oid *argtypes,
Datum *Values, const char *Nulls,
bool read_only, int cursorOptions)
{
Portal result;
_SPI_plan plan;
ParamListInfo paramLI;
if (src == NULL || nargs < 0)
elog(ERROR, "SPI_cursor_open_with_args called with invalid arguments");
if (nargs > 0 && (argtypes == NULL || Values == NULL))
elog(ERROR, "SPI_cursor_open_with_args called with missing parameters");
SPI_result = _SPI_begin_call(true);
if (SPI_result < 0)
elog(ERROR, "SPI_cursor_open_with_args called while not connected");
memset(&plan, 0, sizeof(_SPI_plan));
plan.magic = _SPI_PLAN_MAGIC;
plan.cursor_options = cursorOptions;
plan.nargs = nargs;
plan.argtypes = argtypes;
plan.parserSetup = NULL;
plan.parserSetupArg = NULL;
/* build transient ParamListInfo in executor context */
paramLI = _SPI_convert_params(nargs, argtypes,
Values, Nulls,
PARAM_FLAG_CONST);
_SPI_prepare_plan(src, &plan, paramLI);
/* We needn't copy the plan; SPI_cursor_open_internal will do so */
/* Adjust stack so that SPI_cursor_open_internal doesn't complain */
_SPI_curid--;
/* SPI_cursor_open_internal must be called in procedure memory context */
_SPI_procmem();
result = SPI_cursor_open_internal(name, &plan, paramLI, read_only);
/* And clean up */
_SPI_curid++;
_SPI_end_call(true);
return result;
}
/*
* SPI_cursor_open_with_paramlist()
*
* Same as SPI_cursor_open except that parameters (if any) are passed
* as a ParamListInfo, which supports dynamic parameter set determination
*/
Portal
SPI_cursor_open_with_paramlist(const char *name, SPIPlanPtr plan,
ParamListInfo params, bool read_only)
{
return SPI_cursor_open_internal(name, plan, params, read_only);
}
/*
* SPI_cursor_open_internal()
*
* Common code for SPI_cursor_open variants
*/
static Portal
SPI_cursor_open_internal(const char *name, SPIPlanPtr plan,
ParamListInfo paramLI, bool read_only)
{
CachedPlanSource *plansource;
CachedPlan *cplan;
List *stmt_list;
char *query_string;
Snapshot snapshot;
MemoryContext oldcontext;
Portal portal;
/*
* Check that the plan is something the Portal code will special-case as
* returning one tupleset.
*/
if (!SPI_is_cursor_plan(plan))
{
/* try to give a good error message */
if (list_length(plan->plancache_list) != 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_CURSOR_DEFINITION),
errmsg("cannot open multi-query plan as cursor")));
plansource = (CachedPlanSource *) linitial(plan->plancache_list);
ereport(ERROR,
(errcode(ERRCODE_INVALID_CURSOR_DEFINITION),
/* translator: %s is name of a SQL command, eg INSERT */
errmsg("cannot open %s query as cursor",
plansource->commandTag)));
}
Assert(list_length(plan->plancache_list) == 1);
plansource = (CachedPlanSource *) linitial(plan->plancache_list);
/* Push the SPI stack */
if (_SPI_begin_call(false) < 0)
elog(ERROR, "SPI_cursor_open called while not connected");
/* Reset SPI result (note we deliberately don't touch lastoid) */
SPI_processed = 0;
SPI_tuptable = NULL;
_SPI_current->processed = 0;
_SPI_current->tuptable = NULL;
/* Create the portal */
if (name == NULL || name[0] == '\0')
{
/* Use a random nonconflicting name */
portal = CreateNewPortal();
}
else
{
/* In this path, error if portal of same name already exists */
portal = CreatePortal(name, false, false);
}
/* Copy the plan's query string into the portal */
query_string = MemoryContextStrdup(PortalGetHeapMemory(portal),
plansource->query_string);
/*
* Note: we mustn't have any failure occur between RevalidateCachedPlan
* and PortalDefineQuery; that would result in leaking our plancache
* refcount.
*/
if (plan->saved)
{
/* Replan if needed, and increment plan refcount for portal */
cplan = RevalidateCachedPlan(plansource, false);
stmt_list = cplan->stmt_list;
}
else
{
/* No replan, but copy the plan into the portal's context */
oldcontext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
stmt_list = copyObject(plansource->plan->stmt_list);
MemoryContextSwitchTo(oldcontext);
cplan = NULL; /* portal shouldn't depend on cplan */
}
/*
* Set up the portal.
*/
PortalDefineQuery(portal,
NULL, /* no statement name */
query_string,
plansource->commandTag,
stmt_list,
cplan);
/*
* Set up options for portal. Default SCROLL type is chosen the same way
* as PerformCursorOpen does it.
*/
portal->cursorOptions = plan->cursor_options;
if (!(portal->cursorOptions & (CURSOR_OPT_SCROLL | CURSOR_OPT_NO_SCROLL)))
{
if (list_length(stmt_list) == 1 &&
IsA((Node *) linitial(stmt_list), PlannedStmt) &&
((PlannedStmt *) linitial(stmt_list))->rowMarks == NIL &&
ExecSupportsBackwardScan(((PlannedStmt *) linitial(stmt_list))->planTree))
portal->cursorOptions |= CURSOR_OPT_SCROLL;
else
portal->cursorOptions |= CURSOR_OPT_NO_SCROLL;
}
/*
* Disallow SCROLL with SELECT FOR UPDATE. This is not redundant with the
* check in transformDeclareCursorStmt because the cursor options might
* not have come through there.
*/
if (portal->cursorOptions & CURSOR_OPT_SCROLL)
{
if (list_length(stmt_list) == 1 &&
IsA((Node *) linitial(stmt_list), PlannedStmt) &&
((PlannedStmt *) linitial(stmt_list))->rowMarks != NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("DECLARE SCROLL CURSOR ... FOR UPDATE/SHARE is not supported"),
errdetail("Scrollable cursors must be READ ONLY.")));
}
/*
* If told to be read-only, we'd better check for read-only queries. This
* can't be done earlier because we need to look at the finished, planned
* queries. (In particular, we don't want to do it between
* RevalidateCachedPlan and PortalDefineQuery, because throwing an error
* between those steps would result in leaking our plancache refcount.)
*/
if (read_only)
{
ListCell *lc;
foreach(lc, stmt_list)
{
Node *pstmt = (Node *) lfirst(lc);
if (!CommandIsReadOnly(pstmt))
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(pstmt))));
}
}
/* Set up the snapshot to use. */
if (read_only)
snapshot = GetActiveSnapshot();
else
{
CommandCounterIncrement();
snapshot = GetTransactionSnapshot();
}
/*
* If the plan has parameters, copy them into the portal. Note that this
* must be done after revalidating the plan, because in dynamic parameter
* cases the set of parameters could have changed during re-parsing.
*/
if (paramLI)
{
oldcontext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
paramLI = copyParamList(paramLI);
MemoryContextSwitchTo(oldcontext);
}
/*
* Start portal execution.
*/
PortalStart(portal, paramLI, snapshot);
Assert(portal->strategy != PORTAL_MULTI_QUERY);
/* Pop the SPI stack */
_SPI_end_call(false);
/* Return the created portal */
return portal;
}
/*
* SPI_cursor_find()
*
* Find the portal of an existing open cursor
*/
Portal
SPI_cursor_find(const char *name)
{
return GetPortalByName(name);
}
/*
* SPI_cursor_fetch()
*
* Fetch rows in a cursor
*/
void
SPI_cursor_fetch(Portal portal, bool forward, long count)
{
_SPI_cursor_operation(portal,
forward ? FETCH_FORWARD : FETCH_BACKWARD, count,
CreateDestReceiver(DestSPI));
/* we know that the DestSPI receiver doesn't need a destroy call */
}
/*
* SPI_cursor_move()
*
* Move in a cursor
*/
void
SPI_cursor_move(Portal portal, bool forward, long count)
{
_SPI_cursor_operation(portal,
forward ? FETCH_FORWARD : FETCH_BACKWARD, count,
None_Receiver);
}
/*
* SPI_scroll_cursor_fetch()
*
* Fetch rows in a scrollable cursor
*/
void
SPI_scroll_cursor_fetch(Portal portal, FetchDirection direction, long count)
{
_SPI_cursor_operation(portal,
direction, count,
CreateDestReceiver(DestSPI));
/* we know that the DestSPI receiver doesn't need a destroy call */
}
/*
* SPI_scroll_cursor_move()
*
* Move in a scrollable cursor
*/
void
SPI_scroll_cursor_move(Portal portal, FetchDirection direction, long count)
{
_SPI_cursor_operation(portal, direction, count, None_Receiver);
}
/*
* SPI_cursor_close()
*
* Close a cursor
*/
void
SPI_cursor_close(Portal portal)
{
if (!PortalIsValid(portal))
elog(ERROR, "invalid portal in SPI cursor operation");
PortalDrop(portal, false);
}
/*
* Returns the Oid representing the type id for argument at argIndex. First
* parameter is at index zero.
*/
Oid
SPI_getargtypeid(SPIPlanPtr plan, int argIndex)
{
if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC ||
argIndex < 0 || argIndex >= plan->nargs)
{
SPI_result = SPI_ERROR_ARGUMENT;
return InvalidOid;
}
return plan->argtypes[argIndex];
}
/*
* Returns the number of arguments for the prepared plan.
*/
int
SPI_getargcount(SPIPlanPtr plan)
{
if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC)
{
SPI_result = SPI_ERROR_ARGUMENT;
return -1;
}
return plan->nargs;
}
/*
* Returns true if the plan contains exactly one command
* and that command returns tuples to the caller (eg, SELECT or
* INSERT ... RETURNING, but not SELECT ... INTO). In essence,
* the result indicates if the command can be used with SPI_cursor_open
*
* Parameters
* plan: A plan previously prepared using SPI_prepare
*/
bool
SPI_is_cursor_plan(SPIPlanPtr plan)
{
CachedPlanSource *plansource;
CachedPlan *cplan;
if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC)
{
SPI_result = SPI_ERROR_ARGUMENT;
return false;
}
if (list_length(plan->plancache_list) != 1)
{
SPI_result = 0;
return false; /* not exactly 1 pre-rewrite command */
}
plansource = (CachedPlanSource *) linitial(plan->plancache_list);
/* Need _SPI_begin_call in case replanning invokes SPI-using functions */
SPI_result = _SPI_begin_call(false);
if (SPI_result < 0)
return false;
if (plan->saved)
{
/* Make sure the plan is up to date */
cplan = RevalidateCachedPlan(plansource, true);
ReleaseCachedPlan(cplan, true);
}
_SPI_end_call(false);
SPI_result = 0;
/* Does it return tuples? */
if (plansource->resultDesc)
return true;
return false;
}
/*
* SPI_plan_is_valid --- test whether a SPI plan is currently valid
* (that is, not marked as being in need of revalidation).
*
* See notes for CachedPlanIsValid before using this.
*/
bool
SPI_plan_is_valid(SPIPlanPtr plan)
{
Assert(plan->magic == _SPI_PLAN_MAGIC);
if (plan->saved)
{
ListCell *lc;
foreach(lc, plan->plancache_list)
{
CachedPlanSource *plansource = (CachedPlanSource *) lfirst(lc);
if (!CachedPlanIsValid(plansource))
return false;
}
return true;
}
else
{
/* An unsaved plan is assumed valid for its (short) lifetime */
return true;
}
}
/*
* SPI_result_code_string --- convert any SPI return code to a string
*
* This is often useful in error messages. Most callers will probably
* only pass negative (error-case) codes, but for generality we recognize
* the success codes too.
*/
const char *
SPI_result_code_string(int code)
{
static char buf[64];
switch (code)
{
case SPI_ERROR_CONNECT:
return "SPI_ERROR_CONNECT";
case SPI_ERROR_COPY:
return "SPI_ERROR_COPY";
case SPI_ERROR_OPUNKNOWN:
return "SPI_ERROR_OPUNKNOWN";
case SPI_ERROR_UNCONNECTED:
return "SPI_ERROR_UNCONNECTED";
case SPI_ERROR_ARGUMENT:
return "SPI_ERROR_ARGUMENT";
case SPI_ERROR_PARAM:
return "SPI_ERROR_PARAM";
case SPI_ERROR_TRANSACTION:
return "SPI_ERROR_TRANSACTION";
case SPI_ERROR_NOATTRIBUTE:
return "SPI_ERROR_NOATTRIBUTE";
case SPI_ERROR_NOOUTFUNC:
return "SPI_ERROR_NOOUTFUNC";
case SPI_ERROR_TYPUNKNOWN:
return "SPI_ERROR_TYPUNKNOWN";
case SPI_OK_CONNECT:
return "SPI_OK_CONNECT";
case SPI_OK_FINISH:
return "SPI_OK_FINISH";
case SPI_OK_FETCH:
return "SPI_OK_FETCH";
case SPI_OK_UTILITY:
return "SPI_OK_UTILITY";
case SPI_OK_SELECT:
return "SPI_OK_SELECT";
case SPI_OK_SELINTO:
return "SPI_OK_SELINTO";
case SPI_OK_INSERT:
return "SPI_OK_INSERT";
case SPI_OK_DELETE:
return "SPI_OK_DELETE";
case SPI_OK_UPDATE:
return "SPI_OK_UPDATE";
case SPI_OK_CURSOR:
return "SPI_OK_CURSOR";
case SPI_OK_INSERT_RETURNING:
return "SPI_OK_INSERT_RETURNING";
case SPI_OK_DELETE_RETURNING:
return "SPI_OK_DELETE_RETURNING";
case SPI_OK_UPDATE_RETURNING:
return "SPI_OK_UPDATE_RETURNING";
case SPI_OK_REWRITTEN:
return "SPI_OK_REWRITTEN";
}
/* Unrecognized code ... return something useful ... */
sprintf(buf, "Unrecognized SPI code %d", code);
return buf;
}
/* =================== private functions =================== */
/*
* spi_dest_startup
* Initialize to receive tuples from Executor into SPITupleTable
* of current SPI procedure
*/
void
spi_dest_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
{
SPITupleTable *tuptable;
MemoryContext oldcxt;
MemoryContext tuptabcxt;
/*
* When called by Executor _SPI_curid expected to be equal to
* _SPI_connected
*/
if (_SPI_curid != _SPI_connected || _SPI_connected < 0)
elog(ERROR, "improper call to spi_dest_startup");
if (_SPI_current != &(_SPI_stack[_SPI_curid]))
elog(ERROR, "SPI stack corrupted");
if (_SPI_current->tuptable != NULL)
elog(ERROR, "improper call to spi_dest_startup");
oldcxt = _SPI_procmem(); /* switch to procedure memory context */
tuptabcxt = AllocSetContextCreate(CurrentMemoryContext,
"SPI TupTable",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
MemoryContextSwitchTo(tuptabcxt);
_SPI_current->tuptable = tuptable = (SPITupleTable *)
palloc(sizeof(SPITupleTable));
tuptable->tuptabcxt = tuptabcxt;
tuptable->alloced = tuptable->free = 128;
tuptable->vals = (HeapTuple *) palloc(tuptable->alloced * sizeof(HeapTuple));
tuptable->tupdesc = CreateTupleDescCopy(typeinfo);
MemoryContextSwitchTo(oldcxt);
}
/*
* spi_printtup
* store tuple retrieved by Executor into SPITupleTable
* of current SPI procedure
*/
void
spi_printtup(TupleTableSlot *slot, DestReceiver *self)
{
SPITupleTable *tuptable;
MemoryContext oldcxt;
/*
* When called by Executor _SPI_curid expected to be equal to
* _SPI_connected
*/
if (_SPI_curid != _SPI_connected || _SPI_connected < 0)
elog(ERROR, "improper call to spi_printtup");
if (_SPI_current != &(_SPI_stack[_SPI_curid]))
elog(ERROR, "SPI stack corrupted");
tuptable = _SPI_current->tuptable;
if (tuptable == NULL)
elog(ERROR, "improper call to spi_printtup");
oldcxt = MemoryContextSwitchTo(tuptable->tuptabcxt);
if (tuptable->free == 0)
{
tuptable->free = 256;
tuptable->alloced += tuptable->free;
tuptable->vals = (HeapTuple *) repalloc(tuptable->vals,
tuptable->alloced * sizeof(HeapTuple));
}
tuptable->vals[tuptable->alloced - tuptable->free] =
ExecCopySlotTuple(slot);
(tuptable->free)--;
MemoryContextSwitchTo(oldcxt);
}
/*
* Static functions
*/
/*
* Parse and plan a querystring.
*
* At entry, plan->argtypes and plan->nargs (or alternatively plan->parserSetup
* and plan->parserSetupArg) must be valid, as must plan->cursor_options.
* If boundParams isn't NULL then it represents parameter values that are made
* available to the planner (as either estimates or hard values depending on
* their PARAM_FLAG_CONST marking). The boundParams had better match the
* param type information embedded in the plan!
*
* Results are stored into *plan (specifically, plan->plancache_list).
* Note however that the result trees are all in CurrentMemoryContext
* and need to be copied somewhere to survive.
*/
static void
_SPI_prepare_plan(const char *src, SPIPlanPtr plan, ParamListInfo boundParams)
{
List *raw_parsetree_list;
List *plancache_list;
ListCell *list_item;
ErrorContextCallback spierrcontext;
int cursor_options = plan->cursor_options;
/*
* Setup error traceback support for ereport()
*/
spierrcontext.callback = _SPI_error_callback;
spierrcontext.arg = (void *) src;
spierrcontext.previous = error_context_stack;
error_context_stack = &spierrcontext;
/*
* Parse the request string into a list of raw parse trees.
*/
raw_parsetree_list = pg_parse_query(src);
/*
* Do parse analysis, rule rewrite, and planning for each raw parsetree,
* then cons up a phony plancache entry for each one.
*/
plancache_list = NIL;
foreach(list_item, raw_parsetree_list)
{
Node *parsetree = (Node *) lfirst(list_item);
List *stmt_list;
CachedPlanSource *plansource;
CachedPlan *cplan;
/*
* Parameter datatypes are driven by parserSetup hook if provided,
* otherwise we use the fixed parameter list.
*/
if (plan->parserSetup != NULL)
{
Assert(plan->nargs == 0);
/* Need a copyObject here to keep parser from modifying raw tree */
stmt_list = pg_analyze_and_rewrite_params(copyObject(parsetree),
src,
plan->parserSetup,
plan->parserSetupArg);
}
else
{
/* Need a copyObject here to keep parser from modifying raw tree */
stmt_list = pg_analyze_and_rewrite(copyObject(parsetree),
src,
plan->argtypes,
plan->nargs);
}
stmt_list = pg_plan_queries(stmt_list, cursor_options, boundParams);
plansource = (CachedPlanSource *) palloc0(sizeof(CachedPlanSource));
cplan = (CachedPlan *) palloc0(sizeof(CachedPlan));
plansource->raw_parse_tree = parsetree;
/* cast-away-const here is a bit ugly, but there's no reason to copy */
plansource->query_string = (char *) src;
plansource->commandTag = CreateCommandTag(parsetree);
plansource->param_types = plan->argtypes;
plansource->num_params = plan->nargs;
plansource->parserSetup = plan->parserSetup;
plansource->parserSetupArg = plan->parserSetupArg;
plansource->fully_planned = true;
plansource->fixed_result = false;
/* no need to set search_path, generation or saved_xmin */
plansource->resultDesc = PlanCacheComputeResultDesc(stmt_list);
plansource->plan = cplan;
cplan->stmt_list = stmt_list;
cplan->fully_planned = true;
plancache_list = lappend(plancache_list, plansource);
}
plan->plancache_list = plancache_list;
/*
* Pop the error context stack
*/
error_context_stack = spierrcontext.previous;
}
/*
* Execute the given plan with the given parameter values
*
* snapshot: query snapshot to use, or InvalidSnapshot for the normal
* behavior of taking a new snapshot for each query.
* crosscheck_snapshot: for RI use, all others pass InvalidSnapshot
* read_only: TRUE for read-only execution (no CommandCounterIncrement)
* fire_triggers: TRUE to fire AFTER triggers at end of query (normal case);
* FALSE means any AFTER triggers are postponed to end of outer query
* tcount: execution tuple-count limit, or 0 for none
*/
static int
_SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
Snapshot snapshot, Snapshot crosscheck_snapshot,
bool read_only, bool fire_triggers, long tcount)
{
int my_res = 0;
uint32 my_processed = 0;
Oid my_lastoid = InvalidOid;
SPITupleTable *my_tuptable = NULL;
int res = 0;
bool pushed_active_snap = false;
ErrorContextCallback spierrcontext;
CachedPlan *cplan = NULL;
ListCell *lc1;
/*
* Setup error traceback support for ereport()
*/
spierrcontext.callback = _SPI_error_callback;
spierrcontext.arg = NULL;
spierrcontext.previous = error_context_stack;
error_context_stack = &spierrcontext;
/*
* We support four distinct snapshot management behaviors:
*
* snapshot != InvalidSnapshot, read_only = true: use exactly the given
* snapshot.
*
* snapshot != InvalidSnapshot, read_only = false: use the given snapshot,
* modified by advancing its command ID before each querytree.
*
* snapshot == InvalidSnapshot, read_only = true: use the entry-time
* ActiveSnapshot, if any (if there isn't one, we run with no snapshot).
*
* snapshot == InvalidSnapshot, read_only = false: take a full new
* snapshot for each user command, and advance its command ID before each
* querytree within the command.
*
* In the first two cases, we can just push the snap onto the stack once
* for the whole plan list.
*/
if (snapshot != InvalidSnapshot)
{
if (read_only)
{
PushActiveSnapshot(snapshot);
pushed_active_snap = true;
}
else
{
/* Make sure we have a private copy of the snapshot to modify */
PushCopiedSnapshot(snapshot);
pushed_active_snap = true;
}
}
foreach(lc1, plan->plancache_list)
{
CachedPlanSource *plansource = (CachedPlanSource *) lfirst(lc1);
List *stmt_list;
ListCell *lc2;
spierrcontext.arg = (void *) plansource->query_string;
if (plan->saved)
{
/* Replan if needed, and increment plan refcount locally */
cplan = RevalidateCachedPlan(plansource, true);
stmt_list = cplan->stmt_list;
}
else
{
/* No replan here */
cplan = NULL;
stmt_list = plansource->plan->stmt_list;
}
/*
* In the default non-read-only case, get a new snapshot, replacing
* any that we pushed in a previous cycle.
*/
if (snapshot == InvalidSnapshot && !read_only)
{
if (pushed_active_snap)
PopActiveSnapshot();
PushActiveSnapshot(GetTransactionSnapshot());
pushed_active_snap = true;
}
foreach(lc2, stmt_list)
{
Node *stmt = (Node *) lfirst(lc2);
bool canSetTag;
DestReceiver *dest;
_SPI_current->processed = 0;
_SPI_current->lastoid = InvalidOid;
_SPI_current->tuptable = NULL;
if (IsA(stmt, PlannedStmt))
{
canSetTag = ((PlannedStmt *) stmt)->canSetTag;
}
else
{
/* utilities are canSetTag if only thing in list */
canSetTag = (list_length(stmt_list) == 1);
if (IsA(stmt, CopyStmt))
{
CopyStmt *cstmt = (CopyStmt *) stmt;
if (cstmt->filename == NULL)
{
my_res = SPI_ERROR_COPY;
goto fail;
}
}
else if (IsA(stmt, TransactionStmt))
{
my_res = SPI_ERROR_TRANSACTION;
goto fail;
}
}
if (read_only && !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))));
/*
* If not read-only mode, advance the command counter before each
* command and update the snapshot.
*/
if (!read_only)
{
CommandCounterIncrement();
UpdateActiveSnapshotCommandId();
}
dest = CreateDestReceiver(canSetTag ? DestSPI : DestNone);
if (IsA(stmt, PlannedStmt) &&
((PlannedStmt *) stmt)->utilityStmt == NULL)
{
QueryDesc *qdesc;
Snapshot snap;
if (ActiveSnapshotSet())
snap = GetActiveSnapshot();
else
snap = InvalidSnapshot;
qdesc = CreateQueryDesc((PlannedStmt *) stmt,
plansource->query_string,
snap, crosscheck_snapshot,
dest,
paramLI, 0);
res = _SPI_pquery(qdesc, fire_triggers,
canSetTag ? tcount : 0);
FreeQueryDesc(qdesc);
}
else
{
ProcessUtility(stmt,
plansource->query_string,
paramLI,
false, /* not top level */
dest,
NULL);
/* Update "processed" if stmt returned tuples */
if (_SPI_current->tuptable)
_SPI_current->processed = _SPI_current->tuptable->alloced -
_SPI_current->tuptable->free;
res = SPI_OK_UTILITY;
}
/*
* The last canSetTag query sets the status values returned to the
* caller. Be careful to free any tuptables not returned, to
* avoid intratransaction memory leak.
*/
if (canSetTag)
{
my_processed = _SPI_current->processed;
my_lastoid = _SPI_current->lastoid;
SPI_freetuptable(my_tuptable);
my_tuptable = _SPI_current->tuptable;
my_res = res;
}
else
{
SPI_freetuptable(_SPI_current->tuptable);
_SPI_current->tuptable = NULL;
}
/* we know that the receiver doesn't need a destroy call */
if (res < 0)
{
my_res = res;
goto fail;
}
}
/* Done with this plan, so release refcount */
if (cplan)
ReleaseCachedPlan(cplan, true);
cplan = NULL;
/*
* If not read-only mode, advance the command counter after the last
* command. This ensures that its effects are visible, in case it was
* DDL that would affect the next CachedPlanSource.
*/
if (!read_only)
CommandCounterIncrement();
}
fail:
/* Pop the snapshot off the stack if we pushed one */
if (pushed_active_snap)
PopActiveSnapshot();
/* We no longer need the cached plan refcount, if any */
if (cplan)
ReleaseCachedPlan(cplan, true);
/*
* Pop the error context stack
*/
error_context_stack = spierrcontext.previous;
/* Save results for caller */
SPI_processed = my_processed;
SPI_lastoid = my_lastoid;
SPI_tuptable = my_tuptable;
/* tuptable now is caller's responsibility, not SPI's */
_SPI_current->tuptable = NULL;
/*
* If none of the queries had canSetTag, return SPI_OK_REWRITTEN. Prior to
* 8.4, we used return the last query's result code, but not its auxiliary
* results, but that's confusing.
*/
if (my_res == 0)
my_res = SPI_OK_REWRITTEN;
return my_res;
}
/*
* Convert arrays of query parameters to form wanted by planner and executor
*/
static ParamListInfo
_SPI_convert_params(int nargs, Oid *argtypes,
Datum *Values, const char *Nulls,
int pflags)
{
ParamListInfo paramLI;
if (nargs > 0)
{
int i;
/* sizeof(ParamListInfoData) includes the first array element */
paramLI = (ParamListInfo) palloc(sizeof(ParamListInfoData) +
(nargs - 1) * sizeof(ParamExternData));
/* we have static list of params, so no hooks needed */
paramLI->paramFetch = NULL;
paramLI->paramFetchArg = NULL;
paramLI->parserSetup = NULL;
paramLI->parserSetupArg = NULL;
paramLI->numParams = nargs;
for (i = 0; i < nargs; i++)
{
ParamExternData *prm = &paramLI->params[i];
prm->value = Values[i];
prm->isnull = (Nulls && Nulls[i] == 'n');
prm->pflags = pflags;
prm->ptype = argtypes[i];
}
}
else
paramLI = NULL;
return paramLI;
}
static int
_SPI_pquery(QueryDesc *queryDesc, bool fire_triggers, long tcount)
{
int operation = queryDesc->operation;
int eflags;
int res;
switch (operation)
{
case CMD_SELECT:
Assert(queryDesc->plannedstmt->utilityStmt == NULL);
if (queryDesc->plannedstmt->intoClause) /* select into table? */
res = SPI_OK_SELINTO;
else if (queryDesc->dest->mydest != DestSPI)
{
/* Don't return SPI_OK_SELECT if we're discarding result */
res = SPI_OK_UTILITY;
}
else
res = SPI_OK_SELECT;
break;
case CMD_INSERT:
if (queryDesc->plannedstmt->hasReturning)
res = SPI_OK_INSERT_RETURNING;
else
res = SPI_OK_INSERT;
break;
case CMD_DELETE:
if (queryDesc->plannedstmt->hasReturning)
res = SPI_OK_DELETE_RETURNING;
else
res = SPI_OK_DELETE;
break;
case CMD_UPDATE:
if (queryDesc->plannedstmt->hasReturning)
res = SPI_OK_UPDATE_RETURNING;
else
res = SPI_OK_UPDATE;
break;
default:
return SPI_ERROR_OPUNKNOWN;
}
#ifdef SPI_EXECUTOR_STATS
if (ShowExecutorStats)
ResetUsage();
#endif
/* Select execution options */
if (fire_triggers)
eflags = 0; /* default run-to-completion flags */
else
eflags = EXEC_FLAG_SKIP_TRIGGERS;
ExecutorStart(queryDesc, eflags);
ExecutorRun(queryDesc, ForwardScanDirection, tcount);
_SPI_current->processed = queryDesc->estate->es_processed;
_SPI_current->lastoid = queryDesc->estate->es_lastoid;
if ((res == SPI_OK_SELECT || queryDesc->plannedstmt->hasReturning) &&
queryDesc->dest->mydest == DestSPI)
{
if (_SPI_checktuples())
elog(ERROR, "consistency check on SPI tuple count failed");
}
ExecutorFinish(queryDesc);
ExecutorEnd(queryDesc);
/* FreeQueryDesc is done by the caller */
#ifdef SPI_EXECUTOR_STATS
if (ShowExecutorStats)
ShowUsage("SPI EXECUTOR STATS");
#endif
return res;
}
/*
* _SPI_error_callback
*
* Add context information when a query invoked via SPI fails
*/
static void
_SPI_error_callback(void *arg)
{
const char *query = (const char *) arg;
int syntaxerrposition;
/*
* If there is a syntax error position, convert to internal syntax error;
* otherwise treat the query as an item of context stack
*/
syntaxerrposition = geterrposition();
if (syntaxerrposition > 0)
{
errposition(0);
internalerrposition(syntaxerrposition);
internalerrquery(query);
}
else
errcontext("SQL statement \"%s\"", query);
}
/*
* _SPI_cursor_operation()
*
* Do a FETCH or MOVE in a cursor
*/
static void
_SPI_cursor_operation(Portal portal, FetchDirection direction, long count,
DestReceiver *dest)
{
long nfetched;
/* Check that the portal is valid */
if (!PortalIsValid(portal))
elog(ERROR, "invalid portal in SPI cursor operation");
/* Push the SPI stack */
if (_SPI_begin_call(true) < 0)
elog(ERROR, "SPI cursor operation called while not connected");
/* Reset the SPI result (note we deliberately don't touch lastoid) */
SPI_processed = 0;
SPI_tuptable = NULL;
_SPI_current->processed = 0;
_SPI_current->tuptable = NULL;
/* Run the cursor */
nfetched = PortalRunFetch(portal,
direction,
count,
dest);
/*
* Think not to combine this store with the preceding function call. If
* the portal contains calls to functions that use SPI, then SPI_stack is
* likely to move around while the portal runs. When control returns,
* _SPI_current will point to the correct stack entry... but the pointer
* may be different than it was beforehand. So we must be sure to re-fetch
* the pointer after the function call completes.
*/
_SPI_current->processed = nfetched;
if (dest->mydest == DestSPI && _SPI_checktuples())
elog(ERROR, "consistency check on SPI tuple count failed");
/* Put the result into place for access by caller */
SPI_processed = _SPI_current->processed;
SPI_tuptable = _SPI_current->tuptable;
/* tuptable now is caller's responsibility, not SPI's */
_SPI_current->tuptable = NULL;
/* Pop the SPI stack */
_SPI_end_call(true);
}
static MemoryContext
_SPI_execmem(void)
{
return MemoryContextSwitchTo(_SPI_current->execCxt);
}
static MemoryContext
_SPI_procmem(void)
{
return MemoryContextSwitchTo(_SPI_current->procCxt);
}
/*
* _SPI_begin_call: begin a SPI operation within a connected procedure
*/
static int
_SPI_begin_call(bool execmem)
{
if (_SPI_curid + 1 != _SPI_connected)
return SPI_ERROR_UNCONNECTED;
_SPI_curid++;
if (_SPI_current != &(_SPI_stack[_SPI_curid]))
elog(ERROR, "SPI stack corrupted");
if (execmem) /* switch to the Executor memory context */
_SPI_execmem();
return 0;
}
/*
* _SPI_end_call: end a SPI operation within a connected procedure
*
* Note: this currently has no failure return cases, so callers don't check
*/
static int
_SPI_end_call(bool procmem)
{
/*
* We're returning to procedure where _SPI_curid == _SPI_connected - 1
*/
_SPI_curid--;
if (procmem) /* switch to the procedure memory context */
{
_SPI_procmem();
/* and free Executor memory */
MemoryContextResetAndDeleteChildren(_SPI_current->execCxt);
}
return 0;
}
static bool
_SPI_checktuples(void)
{
uint32 processed = _SPI_current->processed;
SPITupleTable *tuptable = _SPI_current->tuptable;
bool failed = false;
if (tuptable == NULL) /* spi_dest_startup was not called */
failed = true;
else if (processed != (tuptable->alloced - tuptable->free))
failed = true;
return failed;
}
/*
* Make an "unsaved" copy of the given plan, in a child context of parentcxt.
*/
static SPIPlanPtr
_SPI_copy_plan(SPIPlanPtr plan, MemoryContext parentcxt)
{
SPIPlanPtr newplan;
MemoryContext plancxt;
MemoryContext oldcxt;
ListCell *lc;
Assert(!plan->saved); /* not currently supported */
/*
* Create a memory context for the plan. We don't expect the plan to be
* very large, so use smaller-than-default alloc parameters.
*/
plancxt = AllocSetContextCreate(parentcxt,
"SPI Plan",
ALLOCSET_SMALL_MINSIZE,
ALLOCSET_SMALL_INITSIZE,
ALLOCSET_SMALL_MAXSIZE);
oldcxt = MemoryContextSwitchTo(plancxt);
/* Copy the SPI plan into its own context */
newplan = (SPIPlanPtr) palloc(sizeof(_SPI_plan));
newplan->magic = _SPI_PLAN_MAGIC;
newplan->saved = false;
newplan->plancache_list = NIL;
newplan->plancxt = plancxt;
newplan->cursor_options = plan->cursor_options;
newplan->nargs = plan->nargs;
if (plan->nargs > 0)
{
newplan->argtypes = (Oid *) palloc(plan->nargs * sizeof(Oid));
memcpy(newplan->argtypes, plan->argtypes, plan->nargs * sizeof(Oid));
}
else
newplan->argtypes = NULL;
newplan->parserSetup = plan->parserSetup;
newplan->parserSetupArg = plan->parserSetupArg;
foreach(lc, plan->plancache_list)
{
CachedPlanSource *plansource = (CachedPlanSource *) lfirst(lc);
CachedPlanSource *newsource;
CachedPlan *cplan;
CachedPlan *newcplan;
/* Note: we assume we don't need to revalidate the plan */
cplan = plansource->plan;
newsource = (CachedPlanSource *) palloc0(sizeof(CachedPlanSource));
newcplan = (CachedPlan *) palloc0(sizeof(CachedPlan));
newsource->raw_parse_tree = copyObject(plansource->raw_parse_tree);
newsource->query_string = pstrdup(plansource->query_string);
newsource->commandTag = plansource->commandTag;
newsource->param_types = newplan->argtypes;
newsource->num_params = newplan->nargs;
newsource->parserSetup = newplan->parserSetup;
newsource->parserSetupArg = newplan->parserSetupArg;
newsource->fully_planned = plansource->fully_planned;
newsource->fixed_result = plansource->fixed_result;
/* no need to worry about seach_path, generation or saved_xmin */
if (plansource->resultDesc)
newsource->resultDesc = CreateTupleDescCopy(plansource->resultDesc);
newsource->plan = newcplan;
newcplan->stmt_list = copyObject(cplan->stmt_list);
newcplan->fully_planned = cplan->fully_planned;
newplan->plancache_list = lappend(newplan->plancache_list, newsource);
}
MemoryContextSwitchTo(oldcxt);
return newplan;
}
/*
* Make a "saved" copy of the given plan, entrusting everything to plancache.c
*/
static SPIPlanPtr
_SPI_save_plan(SPIPlanPtr plan)
{
SPIPlanPtr newplan;
MemoryContext plancxt;
MemoryContext oldcxt;
ListCell *lc;
Assert(!plan->saved); /* not currently supported */
/*
* Create a memory context for the plan. We don't expect the plan to be
* very large, so use smaller-than-default alloc parameters.
*/
plancxt = AllocSetContextCreate(CacheMemoryContext,
"SPI Plan",
ALLOCSET_SMALL_MINSIZE,
ALLOCSET_SMALL_INITSIZE,
ALLOCSET_SMALL_MAXSIZE);
oldcxt = MemoryContextSwitchTo(plancxt);
/* Copy the SPI plan into its own context */
newplan = (SPIPlanPtr) palloc(sizeof(_SPI_plan));
newplan->magic = _SPI_PLAN_MAGIC;
newplan->saved = true;
newplan->plancache_list = NIL;
newplan->plancxt = plancxt;
newplan->cursor_options = plan->cursor_options;
newplan->nargs = plan->nargs;
if (plan->nargs > 0)
{
newplan->argtypes = (Oid *) palloc(plan->nargs * sizeof(Oid));
memcpy(newplan->argtypes, plan->argtypes, plan->nargs * sizeof(Oid));
}
else
newplan->argtypes = NULL;
newplan->parserSetup = plan->parserSetup;
newplan->parserSetupArg = plan->parserSetupArg;
foreach(lc, plan->plancache_list)
{
CachedPlanSource *plansource = (CachedPlanSource *) lfirst(lc);
CachedPlanSource *newsource;
CachedPlan *cplan;
/* Note: we assume we don't need to revalidate the plan */
cplan = plansource->plan;
newsource = CreateCachedPlan(plansource->raw_parse_tree,
plansource->query_string,
plansource->commandTag,
newplan->argtypes,
newplan->nargs,
newplan->cursor_options,
cplan->stmt_list,
true,
false);
if (newplan->parserSetup != NULL)
CachedPlanSetParserHook(newsource,
newplan->parserSetup,
newplan->parserSetupArg);
newplan->plancache_list = lappend(newplan->plancache_list, newsource);
}
MemoryContextSwitchTo(oldcxt);
return newplan;
}
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