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postgres/src/backend/executor/execMain.c
Tom Lane 651902deb1 Re-run pgindent. 
This is just to have a clean base state for testing of Piotr Stefaniak's
latest version of FreeBSD indent.  I fixed up a couple of places where
pgindent would have changed format not-nicely.  perltidy not included.

Discussion: https://postgr.es/m/VI1PR03MB119959F4B65F000CA7CD9F6BF2CC0@VI1PR03MB1199.eurprd03.prod.outlook.com
2017-06-13 13:05:59 -04:00

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/*-------------------------------------------------------------------------
*
* execMain.c
* top level executor interface routines
*
* INTERFACE ROUTINES
* ExecutorStart()
* ExecutorRun()
* ExecutorFinish()
* ExecutorEnd()
*
* These four procedures are the external interface to the executor.
* In each case, the query descriptor is required as an argument.
*
* ExecutorStart must be called at the beginning of execution of any
* query plan and ExecutorEnd must always be called at the end of
* execution of a plan (unless it is aborted due to error).
*
* ExecutorRun accepts direction and count arguments that specify whether
* the plan is to be executed forwards, backwards, and for how many tuples.
* In some cases ExecutorRun may be called multiple times to process all
* the tuples for a plan. It is also acceptable to stop short of executing
* the whole plan (but only if it is a SELECT).
*
* ExecutorFinish must be called after the final ExecutorRun call and
* before ExecutorEnd. This can be omitted only in case of EXPLAIN,
* which should also omit ExecutorRun.
*
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/executor/execMain.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "access/sysattr.h"
#include "access/transam.h"
#include "access/xact.h"
#include "catalog/namespace.h"
#include "catalog/partition.h"
#include "catalog/pg_publication.h"
#include "commands/matview.h"
#include "commands/trigger.h"
#include "executor/execdebug.h"
#include "foreign/fdwapi.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "optimizer/clauses.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "tcop/utility.h"
#include "utils/acl.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rls.h"
#include "utils/ruleutils.h"
#include "utils/snapmgr.h"
#include "utils/tqual.h"
/* Hooks for plugins to get control in ExecutorStart/Run/Finish/End */
ExecutorStart_hook_type ExecutorStart_hook = NULL;
ExecutorRun_hook_type ExecutorRun_hook = NULL;
ExecutorFinish_hook_type ExecutorFinish_hook = NULL;
ExecutorEnd_hook_type ExecutorEnd_hook = NULL;
/* Hook for plugin to get control in ExecCheckRTPerms() */
ExecutorCheckPerms_hook_type ExecutorCheckPerms_hook = NULL;
/* decls for local routines only used within this module */
static void InitPlan(QueryDesc *queryDesc, int eflags);
static void CheckValidRowMarkRel(Relation rel, RowMarkType markType);
static void ExecPostprocessPlan(EState *estate);
static void ExecEndPlan(PlanState *planstate, EState *estate);
static void ExecutePlan(EState *estate, PlanState *planstate,
bool use_parallel_mode,
CmdType operation,
bool sendTuples,
uint64 numberTuples,
ScanDirection direction,
DestReceiver *dest,
bool execute_once);
static bool ExecCheckRTEPerms(RangeTblEntry *rte);
static bool ExecCheckRTEPermsModified(Oid relOid, Oid userid,
Bitmapset *modifiedCols,
AclMode requiredPerms);
static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt);
static char *ExecBuildSlotValueDescription(Oid reloid,
TupleTableSlot *slot,
TupleDesc tupdesc,
Bitmapset *modifiedCols,
int maxfieldlen);
static char *ExecBuildSlotPartitionKeyDescription(Relation rel,
Datum *values,
bool *isnull,
int maxfieldlen);
static void EvalPlanQualStart(EPQState *epqstate, EState *parentestate,
Plan *planTree);
static void ExecPartitionCheck(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate);
/*
* Note that GetUpdatedColumns() also exists in commands/trigger.c. There does
* not appear to be any good header to put it into, given the structures that
* it uses, so we let them be duplicated. Be sure to update both if one needs
* to be changed, however.
*/
#define GetInsertedColumns(relinfo, estate) \
(rt_fetch((relinfo)->ri_RangeTableIndex, (estate)->es_range_table)->insertedCols)
#define GetUpdatedColumns(relinfo, estate) \
(rt_fetch((relinfo)->ri_RangeTableIndex, (estate)->es_range_table)->updatedCols)
/* end of local decls */
/* ----------------------------------------------------------------
* ExecutorStart
*
* This routine must be called at the beginning of any execution of any
* query plan
*
* Takes a QueryDesc previously created by CreateQueryDesc (which is separate
* only because some places use QueryDescs for utility commands). The tupDesc
* field of the QueryDesc is filled in to describe the tuples that will be
* returned, and the internal fields (estate and planstate) are set up.
*
* eflags contains flag bits as described in executor.h.
*
* NB: the CurrentMemoryContext when this is called will become the parent
* of the per-query context used for this Executor invocation.
*
* We provide a function hook variable that lets loadable plugins
* get control when ExecutorStart is called. Such a plugin would
* normally call standard_ExecutorStart().
*
* ----------------------------------------------------------------
*/
void
ExecutorStart(QueryDesc *queryDesc, int eflags)
{
if (ExecutorStart_hook)
(*ExecutorStart_hook) (queryDesc, eflags);
else
standard_ExecutorStart(queryDesc, eflags);
}
void
standard_ExecutorStart(QueryDesc *queryDesc, int eflags)
{
EState *estate;
MemoryContext oldcontext;
/* sanity checks: queryDesc must not be started already */
Assert(queryDesc != NULL);
Assert(queryDesc->estate == NULL);
/*
* If the transaction is read-only, we need to check if any writes are
* planned to non-temporary tables. EXPLAIN is considered read-only.
*
* Don't allow writes in parallel mode. Supporting UPDATE and DELETE
* would require (a) storing the combocid hash in shared memory, rather
* than synchronizing it just once at the start of parallelism, and (b) an
* alternative to heap_update()'s reliance on xmax for mutual exclusion.
* INSERT may have no such troubles, but we forbid it to simplify the
* checks.
*
* We have lower-level defenses in CommandCounterIncrement and elsewhere
* against performing unsafe operations in parallel mode, but this gives a
* more user-friendly error message.
*/
if ((XactReadOnly || IsInParallelMode()) &&
!(eflags & EXEC_FLAG_EXPLAIN_ONLY))
ExecCheckXactReadOnly(queryDesc->plannedstmt);
/*
* Build EState, switch into per-query memory context for startup.
*/
estate = CreateExecutorState();
queryDesc->estate = estate;
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
/*
* Fill in external parameters, if any, from queryDesc; and allocate
* workspace for internal parameters
*/
estate->es_param_list_info = queryDesc->params;
if (queryDesc->plannedstmt->nParamExec > 0)
estate->es_param_exec_vals = (ParamExecData *)
palloc0(queryDesc->plannedstmt->nParamExec * sizeof(ParamExecData));
estate->es_sourceText = queryDesc->sourceText;
/*
* Fill in the query environment, if any, from queryDesc.
*/
estate->es_queryEnv = queryDesc->queryEnv;
/*
* If non-read-only query, set the command ID to mark output tuples with
*/
switch (queryDesc->operation)
{
case CMD_SELECT:
/*
* SELECT FOR [KEY] UPDATE/SHARE and modifying CTEs need to mark
* tuples
*/
if (queryDesc->plannedstmt->rowMarks != NIL ||
queryDesc->plannedstmt->hasModifyingCTE)
estate->es_output_cid = GetCurrentCommandId(true);
/*
* A SELECT without modifying CTEs can't possibly queue triggers,
* so force skip-triggers mode. This is just a marginal efficiency
* hack, since AfterTriggerBeginQuery/AfterTriggerEndQuery aren't
* all that expensive, but we might as well do it.
*/
if (!queryDesc->plannedstmt->hasModifyingCTE)
eflags |= EXEC_FLAG_SKIP_TRIGGERS;
break;
case CMD_INSERT:
case CMD_DELETE:
case CMD_UPDATE:
estate->es_output_cid = GetCurrentCommandId(true);
break;
default:
elog(ERROR, "unrecognized operation code: %d",
(int) queryDesc->operation);
break;
}
/*
* Copy other important information into the EState
*/
estate->es_snapshot = RegisterSnapshot(queryDesc->snapshot);
estate->es_crosscheck_snapshot = RegisterSnapshot(queryDesc->crosscheck_snapshot);
estate->es_top_eflags = eflags;
estate->es_instrument = queryDesc->instrument_options;
/*
* Initialize the plan state tree
*/
InitPlan(queryDesc, eflags);
/*
* Set up an AFTER-trigger statement context, unless told not to, or
* unless it's EXPLAIN-only mode (when ExecutorFinish won't be called).
*/
if (!(eflags & (EXEC_FLAG_SKIP_TRIGGERS | EXEC_FLAG_EXPLAIN_ONLY)))
AfterTriggerBeginQuery();
MemoryContextSwitchTo(oldcontext);
}
/* ----------------------------------------------------------------
* ExecutorRun
*
* This is the main routine of the executor module. It accepts
* the query descriptor from the traffic cop and executes the
* query plan.
*
* ExecutorStart must have been called already.
*
* If direction is NoMovementScanDirection then nothing is done
* except to start up/shut down the destination. Otherwise,
* we retrieve up to 'count' tuples in the specified direction.
*
* Note: count = 0 is interpreted as no portal limit, i.e., run to
* completion. Also note that the count limit is only applied to
* retrieved tuples, not for instance to those inserted/updated/deleted
* by a ModifyTable plan node.
*
* There is no return value, but output tuples (if any) are sent to
* the destination receiver specified in the QueryDesc; and the number
* of tuples processed at the top level can be found in
* estate->es_processed.
*
* We provide a function hook variable that lets loadable plugins
* get control when ExecutorRun is called. Such a plugin would
* normally call standard_ExecutorRun().
*
* ----------------------------------------------------------------
*/
void
ExecutorRun(QueryDesc *queryDesc,
ScanDirection direction, uint64 count,
bool execute_once)
{
if (ExecutorRun_hook)
(*ExecutorRun_hook) (queryDesc, direction, count, execute_once);
else
standard_ExecutorRun(queryDesc, direction, count, execute_once);
}
void
standard_ExecutorRun(QueryDesc *queryDesc,
ScanDirection direction, uint64 count, bool execute_once)
{
EState *estate;
CmdType operation;
DestReceiver *dest;
bool sendTuples;
MemoryContext oldcontext;
/* sanity checks */
Assert(queryDesc != NULL);
estate = queryDesc->estate;
Assert(estate != NULL);
Assert(!(estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY));
/*
* Switch into per-query memory context
*/
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
/* Allow instrumentation of Executor overall runtime */
if (queryDesc->totaltime)
InstrStartNode(queryDesc->totaltime);
/*
* extract information from the query descriptor and the query feature.
*/
operation = queryDesc->operation;
dest = queryDesc->dest;
/*
* startup tuple receiver, if we will be emitting tuples
*/
estate->es_processed = 0;
estate->es_lastoid = InvalidOid;
sendTuples = (operation == CMD_SELECT ||
queryDesc->plannedstmt->hasReturning);
if (sendTuples)
(*dest->rStartup) (dest, operation, queryDesc->tupDesc);
/*
* run plan
*/
if (!ScanDirectionIsNoMovement(direction))
{
if (execute_once && queryDesc->already_executed)
elog(ERROR, "can't re-execute query flagged for single execution");
queryDesc->already_executed = true;
ExecutePlan(estate,
queryDesc->planstate,
queryDesc->plannedstmt->parallelModeNeeded,
operation,
sendTuples,
count,
direction,
dest,
execute_once);
}
/*
* shutdown tuple receiver, if we started it
*/
if (sendTuples)
(*dest->rShutdown) (dest);
if (queryDesc->totaltime)
InstrStopNode(queryDesc->totaltime, estate->es_processed);
MemoryContextSwitchTo(oldcontext);
}
/* ----------------------------------------------------------------
* ExecutorFinish
*
* This routine must be called after the last ExecutorRun call.
* It performs cleanup such as firing AFTER triggers. It is
* separate from ExecutorEnd because EXPLAIN ANALYZE needs to
* include these actions in the total runtime.
*
* We provide a function hook variable that lets loadable plugins
* get control when ExecutorFinish is called. Such a plugin would
* normally call standard_ExecutorFinish().
*
* ----------------------------------------------------------------
*/
void
ExecutorFinish(QueryDesc *queryDesc)
{
if (ExecutorFinish_hook)
(*ExecutorFinish_hook) (queryDesc);
else
standard_ExecutorFinish(queryDesc);
}
void
standard_ExecutorFinish(QueryDesc *queryDesc)
{
EState *estate;
MemoryContext oldcontext;
/* sanity checks */
Assert(queryDesc != NULL);
estate = queryDesc->estate;
Assert(estate != NULL);
Assert(!(estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY));
/* This should be run once and only once per Executor instance */
Assert(!estate->es_finished);
/* Switch into per-query memory context */
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
/* Allow instrumentation of Executor overall runtime */
if (queryDesc->totaltime)
InstrStartNode(queryDesc->totaltime);
/* Run ModifyTable nodes to completion */
ExecPostprocessPlan(estate);
/* Execute queued AFTER triggers, unless told not to */
if (!(estate->es_top_eflags & EXEC_FLAG_SKIP_TRIGGERS))
AfterTriggerEndQuery(estate);
if (queryDesc->totaltime)
InstrStopNode(queryDesc->totaltime, 0);
MemoryContextSwitchTo(oldcontext);
estate->es_finished = true;
}
/* ----------------------------------------------------------------
* ExecutorEnd
*
* This routine must be called at the end of execution of any
* query plan
*
* We provide a function hook variable that lets loadable plugins
* get control when ExecutorEnd is called. Such a plugin would
* normally call standard_ExecutorEnd().
*
* ----------------------------------------------------------------
*/
void
ExecutorEnd(QueryDesc *queryDesc)
{
if (ExecutorEnd_hook)
(*ExecutorEnd_hook) (queryDesc);
else
standard_ExecutorEnd(queryDesc);
}
void
standard_ExecutorEnd(QueryDesc *queryDesc)
{
EState *estate;
MemoryContext oldcontext;
/* sanity checks */
Assert(queryDesc != NULL);
estate = queryDesc->estate;
Assert(estate != NULL);
/*
* Check that ExecutorFinish was called, unless in EXPLAIN-only mode. This
* Assert is needed because ExecutorFinish is new as of 9.1, and callers
* might forget to call it.
*/
Assert(estate->es_finished ||
(estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY));
/*
* Switch into per-query memory context to run ExecEndPlan
*/
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
ExecEndPlan(queryDesc->planstate, estate);
/* do away with our snapshots */
UnregisterSnapshot(estate->es_snapshot);
UnregisterSnapshot(estate->es_crosscheck_snapshot);
/*
* Must switch out of context before destroying it
*/
MemoryContextSwitchTo(oldcontext);
/*
* Release EState and per-query memory context. This should release
* everything the executor has allocated.
*/
FreeExecutorState(estate);
/* Reset queryDesc fields that no longer point to anything */
queryDesc->tupDesc = NULL;
queryDesc->estate = NULL;
queryDesc->planstate = NULL;
queryDesc->totaltime = NULL;
}
/* ----------------------------------------------------------------
* ExecutorRewind
*
* This routine may be called on an open queryDesc to rewind it
* to the start.
* ----------------------------------------------------------------
*/
void
ExecutorRewind(QueryDesc *queryDesc)
{
EState *estate;
MemoryContext oldcontext;
/* sanity checks */
Assert(queryDesc != NULL);
estate = queryDesc->estate;
Assert(estate != NULL);
/* It's probably not sensible to rescan updating queries */
Assert(queryDesc->operation == CMD_SELECT);
/*
* Switch into per-query memory context
*/
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
/*
* rescan plan
*/
ExecReScan(queryDesc->planstate);
MemoryContextSwitchTo(oldcontext);
}
/*
* ExecCheckRTPerms
* Check access permissions for all relations listed in a range table.
*
* Returns true if permissions are adequate. Otherwise, throws an appropriate
* error if ereport_on_violation is true, or simply returns false otherwise.
*
* Note that this does NOT address row level security policies (aka: RLS). If
* rows will be returned to the user as a result of this permission check
* passing, then RLS also needs to be consulted (and check_enable_rls()).
*
* See rewrite/rowsecurity.c.
*/
bool
ExecCheckRTPerms(List *rangeTable, bool ereport_on_violation)
{
ListCell *l;
bool result = true;
foreach(l, rangeTable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
result = ExecCheckRTEPerms(rte);
if (!result)
{
Assert(rte->rtekind == RTE_RELATION);
if (ereport_on_violation)
aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS,
get_rel_name(rte->relid));
return false;
}
}
if (ExecutorCheckPerms_hook)
result = (*ExecutorCheckPerms_hook) (rangeTable,
ereport_on_violation);
return result;
}
/*
* ExecCheckRTEPerms
* Check access permissions for a single RTE.
*/
static bool
ExecCheckRTEPerms(RangeTblEntry *rte)
{
AclMode requiredPerms;
AclMode relPerms;
AclMode remainingPerms;
Oid relOid;
Oid userid;
/*
* Only plain-relation RTEs need to be checked here. Function RTEs are
* checked when the function is prepared for execution. Join, subquery,
* and special RTEs need no checks.
*/
if (rte->rtekind != RTE_RELATION)
return true;
/*
* No work if requiredPerms is empty.
*/
requiredPerms = rte->requiredPerms;
if (requiredPerms == 0)
return true;
relOid = rte->relid;
/*
* userid to check as: current user unless we have a setuid indication.
*
* Note: GetUserId() is presently fast enough that there's no harm in
* calling it separately for each RTE. If that stops being true, we could
* call it once in ExecCheckRTPerms and pass the userid down from there.
* But for now, no need for the extra clutter.
*/
userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
/*
* We must have *all* the requiredPerms bits, but some of the bits can be
* satisfied from column-level rather than relation-level permissions.
* First, remove any bits that are satisfied by relation permissions.
*/
relPerms = pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL);
remainingPerms = requiredPerms & ~relPerms;
if (remainingPerms != 0)
{
int col = -1;
/*
* If we lack any permissions that exist only as relation permissions,
* we can fail straight away.
*/
if (remainingPerms & ~(ACL_SELECT | ACL_INSERT | ACL_UPDATE))
return false;
/*
* Check to see if we have the needed privileges at column level.
*
* Note: failures just report a table-level error; it would be nicer
* to report a column-level error if we have some but not all of the
* column privileges.
*/
if (remainingPerms & ACL_SELECT)
{
/*
* When the query doesn't explicitly reference any columns (for
* example, SELECT COUNT(*) FROM table), allow the query if we
* have SELECT on any column of the rel, as per SQL spec.
*/
if (bms_is_empty(rte->selectedCols))
{
if (pg_attribute_aclcheck_all(relOid, userid, ACL_SELECT,
ACLMASK_ANY) != ACLCHECK_OK)
return false;
}
while ((col = bms_next_member(rte->selectedCols, col)) >= 0)
{
/* bit #s are offset by FirstLowInvalidHeapAttributeNumber */
AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber;
if (attno == InvalidAttrNumber)
{
/* Whole-row reference, must have priv on all cols */
if (pg_attribute_aclcheck_all(relOid, userid, ACL_SELECT,
ACLMASK_ALL) != ACLCHECK_OK)
return false;
}
else
{
if (pg_attribute_aclcheck(relOid, attno, userid,
ACL_SELECT) != ACLCHECK_OK)
return false;
}
}
}
/*
* Basically the same for the mod columns, for both INSERT and UPDATE
* privilege as specified by remainingPerms.
*/
if (remainingPerms & ACL_INSERT && !ExecCheckRTEPermsModified(relOid,
userid,
rte->insertedCols,
ACL_INSERT))
return false;
if (remainingPerms & ACL_UPDATE && !ExecCheckRTEPermsModified(relOid,
userid,
rte->updatedCols,
ACL_UPDATE))
return false;
}
return true;
}
/*
* ExecCheckRTEPermsModified
* Check INSERT or UPDATE access permissions for a single RTE (these
* are processed uniformly).
*/
static bool
ExecCheckRTEPermsModified(Oid relOid, Oid userid, Bitmapset *modifiedCols,
AclMode requiredPerms)
{
int col = -1;
/*
* When the query doesn't explicitly update any columns, allow the query
* if we have permission on any column of the rel. This is to handle
* SELECT FOR UPDATE as well as possible corner cases in UPDATE.
*/
if (bms_is_empty(modifiedCols))
{
if (pg_attribute_aclcheck_all(relOid, userid, requiredPerms,
ACLMASK_ANY) != ACLCHECK_OK)
return false;
}
while ((col = bms_next_member(modifiedCols, col)) >= 0)
{
/* bit #s are offset by FirstLowInvalidHeapAttributeNumber */
AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber;
if (attno == InvalidAttrNumber)
{
/* whole-row reference can't happen here */
elog(ERROR, "whole-row update is not implemented");
}
else
{
if (pg_attribute_aclcheck(relOid, attno, userid,
requiredPerms) != ACLCHECK_OK)
return false;
}
}
return true;
}
/*
* Check that the query does not imply any writes to non-temp tables;
* unless we're in parallel mode, in which case don't even allow writes
* to temp tables.
*
* Note: in a Hot Standby slave this would need to reject writes to temp
* tables just as we do in parallel mode; but an HS slave can't have created
* any temp tables in the first place, so no need to check that.
*/
static void
ExecCheckXactReadOnly(PlannedStmt *plannedstmt)
{
ListCell *l;
/*
* Fail if write permissions are requested in parallel mode for table
* (temp or non-temp), otherwise fail for any non-temp table.
*/
foreach(l, plannedstmt->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
if (rte->rtekind != RTE_RELATION)
continue;
if ((rte->requiredPerms & (~ACL_SELECT)) == 0)
continue;
if (isTempNamespace(get_rel_namespace(rte->relid)))
continue;
PreventCommandIfReadOnly(CreateCommandTag((Node *) plannedstmt));
}
if (plannedstmt->commandType != CMD_SELECT || plannedstmt->hasModifyingCTE)
PreventCommandIfParallelMode(CreateCommandTag((Node *) plannedstmt));
}
/* ----------------------------------------------------------------
* InitPlan
*
* Initializes the query plan: open files, allocate storage
* and start up the rule manager
* ----------------------------------------------------------------
*/
static void
InitPlan(QueryDesc *queryDesc, int eflags)
{
CmdType operation = queryDesc->operation;
PlannedStmt *plannedstmt = queryDesc->plannedstmt;
Plan *plan = plannedstmt->planTree;
List *rangeTable = plannedstmt->rtable;
EState *estate = queryDesc->estate;
PlanState *planstate;
TupleDesc tupType;
ListCell *l;
int i;
/*
* Do permissions checks
*/
ExecCheckRTPerms(rangeTable, true);
/*
* initialize the node's execution state
*/
estate->es_range_table = rangeTable;
estate->es_plannedstmt = plannedstmt;
/*
* initialize result relation stuff, and open/lock the result rels.
*
* We must do this before initializing the plan tree, else we might try to
* do a lock upgrade if a result rel is also a source rel.
*/
if (plannedstmt->resultRelations)
{
List *resultRelations = plannedstmt->resultRelations;
int numResultRelations = list_length(resultRelations);
ResultRelInfo *resultRelInfos;
ResultRelInfo *resultRelInfo;
resultRelInfos = (ResultRelInfo *)
palloc(numResultRelations * sizeof(ResultRelInfo));
resultRelInfo = resultRelInfos;
foreach(l, resultRelations)
{
Index resultRelationIndex = lfirst_int(l);
Oid resultRelationOid;
Relation resultRelation;
resultRelationOid = getrelid(resultRelationIndex, rangeTable);
resultRelation = heap_open(resultRelationOid, RowExclusiveLock);
InitResultRelInfo(resultRelInfo,
resultRelation,
resultRelationIndex,
NULL,
estate->es_instrument);
resultRelInfo++;
}
estate->es_result_relations = resultRelInfos;
estate->es_num_result_relations = numResultRelations;
/* es_result_relation_info is NULL except when within ModifyTable */
estate->es_result_relation_info = NULL;
/*
* In the partitioned result relation case, lock the non-leaf result
* relations too. A subset of these are the roots of respective
* partitioned tables, for which we also allocate ResulRelInfos.
*/
estate->es_root_result_relations = NULL;
estate->es_num_root_result_relations = 0;
if (plannedstmt->nonleafResultRelations)
{
int num_roots = list_length(plannedstmt->rootResultRelations);
/*
* Firstly, build ResultRelInfos for all the partitioned table
* roots, because we will need them to fire the statement-level
* triggers, if any.
*/
resultRelInfos = (ResultRelInfo *)
palloc(num_roots * sizeof(ResultRelInfo));
resultRelInfo = resultRelInfos;
foreach(l, plannedstmt->rootResultRelations)
{
Index resultRelIndex = lfirst_int(l);
Oid resultRelOid;
Relation resultRelDesc;
resultRelOid = getrelid(resultRelIndex, rangeTable);
resultRelDesc = heap_open(resultRelOid, RowExclusiveLock);
InitResultRelInfo(resultRelInfo,
resultRelDesc,
lfirst_int(l),
NULL,
estate->es_instrument);
resultRelInfo++;
}
estate->es_root_result_relations = resultRelInfos;
estate->es_num_root_result_relations = num_roots;
/* Simply lock the rest of them. */
foreach(l, plannedstmt->nonleafResultRelations)
{
Index resultRelIndex = lfirst_int(l);
/* We locked the roots above. */
if (!list_member_int(plannedstmt->rootResultRelations,
resultRelIndex))
LockRelationOid(getrelid(resultRelIndex, rangeTable),
RowExclusiveLock);
}
}
}
else
{
/*
* if no result relation, then set state appropriately
*/
estate->es_result_relations = NULL;
estate->es_num_result_relations = 0;
estate->es_result_relation_info = NULL;
estate->es_root_result_relations = NULL;
estate->es_num_root_result_relations = 0;
}
/*
* Similarly, we have to lock relations selected FOR [KEY] UPDATE/SHARE
* before we initialize the plan tree, else we'd be risking lock upgrades.
* While we are at it, build the ExecRowMark list. Any partitioned child
* tables are ignored here (because isParent=true) and will be locked by
* the first Append or MergeAppend node that references them. (Note that
* the RowMarks corresponding to partitioned child tables are present in
* the same list as the rest, i.e., plannedstmt->rowMarks.)
*/
estate->es_rowMarks = NIL;
foreach(l, plannedstmt->rowMarks)
{
PlanRowMark *rc = (PlanRowMark *) lfirst(l);
Oid relid;
Relation relation;
ExecRowMark *erm;
/* ignore "parent" rowmarks; they are irrelevant at runtime */
if (rc->isParent)
continue;
/* get relation's OID (will produce InvalidOid if subquery) */
relid = getrelid(rc->rti, rangeTable);
/*
* If you change the conditions under which rel locks are acquired
* here, be sure to adjust ExecOpenScanRelation to match.
*/
switch (rc->markType)
{
case ROW_MARK_EXCLUSIVE:
case ROW_MARK_NOKEYEXCLUSIVE:
case ROW_MARK_SHARE:
case ROW_MARK_KEYSHARE:
relation = heap_open(relid, RowShareLock);
break;
case ROW_MARK_REFERENCE:
relation = heap_open(relid, AccessShareLock);
break;
case ROW_MARK_COPY:
/* no physical table access is required */
relation = NULL;
break;
default:
elog(ERROR, "unrecognized markType: %d", rc->markType);
relation = NULL; /* keep compiler quiet */
break;
}
/* Check that relation is a legal target for marking */
if (relation)
CheckValidRowMarkRel(relation, rc->markType);
erm = (ExecRowMark *) palloc(sizeof(ExecRowMark));
erm->relation = relation;
erm->relid = relid;
erm->rti = rc->rti;
erm->prti = rc->prti;
erm->rowmarkId = rc->rowmarkId;
erm->markType = rc->markType;
erm->strength = rc->strength;
erm->waitPolicy = rc->waitPolicy;
erm->ermActive = false;
ItemPointerSetInvalid(&(erm->curCtid));
erm->ermExtra = NULL;
estate->es_rowMarks = lappend(estate->es_rowMarks, erm);
}
/*
* Initialize the executor's tuple table to empty.
*/
estate->es_tupleTable = NIL;
estate->es_trig_tuple_slot = NULL;
estate->es_trig_oldtup_slot = NULL;
estate->es_trig_newtup_slot = NULL;
/* mark EvalPlanQual not active */
estate->es_epqTuple = NULL;
estate->es_epqTupleSet = NULL;
estate->es_epqScanDone = NULL;
/*
* Initialize private state information for each SubPlan. We must do this
* before running ExecInitNode on the main query tree, since
* ExecInitSubPlan expects to be able to find these entries.
*/
Assert(estate->es_subplanstates == NIL);
i = 1; /* subplan indices count from 1 */
foreach(l, plannedstmt->subplans)
{
Plan *subplan = (Plan *) lfirst(l);
PlanState *subplanstate;
int sp_eflags;
/*
* A subplan will never need to do BACKWARD scan nor MARK/RESTORE. If
* it is a parameterless subplan (not initplan), we suggest that it be
* prepared to handle REWIND efficiently; otherwise there is no need.
*/
sp_eflags = eflags
& (EXEC_FLAG_EXPLAIN_ONLY | EXEC_FLAG_WITH_NO_DATA);
if (bms_is_member(i, plannedstmt->rewindPlanIDs))
sp_eflags |= EXEC_FLAG_REWIND;
subplanstate = ExecInitNode(subplan, estate, sp_eflags);
estate->es_subplanstates = lappend(estate->es_subplanstates,
subplanstate);
i++;
}
/*
* Initialize the private state information for all the nodes in the query
* tree. This opens files, allocates storage and leaves us ready to start
* processing tuples.
*/
planstate = ExecInitNode(plan, estate, eflags);
/*
* Get the tuple descriptor describing the type of tuples to return.
*/
tupType = ExecGetResultType(planstate);
/*
* Initialize the junk filter if needed. SELECT queries need a filter if
* there are any junk attrs in the top-level tlist.
*/
if (operation == CMD_SELECT)
{
bool junk_filter_needed = false;
ListCell *tlist;
foreach(tlist, plan->targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tlist);
if (tle->resjunk)
{
junk_filter_needed = true;
break;
}
}
if (junk_filter_needed)
{
JunkFilter *j;
j = ExecInitJunkFilter(planstate->plan->targetlist,
tupType->tdhasoid,
ExecInitExtraTupleSlot(estate));
estate->es_junkFilter = j;
/* Want to return the cleaned tuple type */
tupType = j->jf_cleanTupType;
}
}
queryDesc->tupDesc = tupType;
queryDesc->planstate = planstate;
}
/*
* Check that a proposed result relation is a legal target for the operation
*
* Generally the parser and/or planner should have noticed any such mistake
* already, but let's make sure.
*
* Note: when changing this function, you probably also need to look at
* CheckValidRowMarkRel.
*/
void
CheckValidResultRel(Relation resultRel, CmdType operation)
{
TriggerDesc *trigDesc = resultRel->trigdesc;
FdwRoutine *fdwroutine;
switch (resultRel->rd_rel->relkind)
{
case RELKIND_RELATION:
case RELKIND_PARTITIONED_TABLE:
CheckCmdReplicaIdentity(resultRel, operation);
break;
case RELKIND_SEQUENCE:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot change sequence \"%s\"",
RelationGetRelationName(resultRel))));
break;
case RELKIND_TOASTVALUE:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot change TOAST relation \"%s\"",
RelationGetRelationName(resultRel))));
break;
case RELKIND_VIEW:
/*
* Okay only if there's a suitable INSTEAD OF trigger. Messages
* here should match rewriteHandler.c's rewriteTargetView, except
* that we omit errdetail because we haven't got the information
* handy (and given that we really shouldn't get here anyway, it's
* not worth great exertion to get).
*/
switch (operation)
{
case CMD_INSERT:
if (!trigDesc || !trigDesc->trig_insert_instead_row)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot insert into view \"%s\"",
RelationGetRelationName(resultRel)),
errhint("To enable inserting into the view, provide an INSTEAD OF INSERT trigger or an unconditional ON INSERT DO INSTEAD rule.")));
break;
case CMD_UPDATE:
if (!trigDesc || !trigDesc->trig_update_instead_row)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot update view \"%s\"",
RelationGetRelationName(resultRel)),
errhint("To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule.")));
break;
case CMD_DELETE:
if (!trigDesc || !trigDesc->trig_delete_instead_row)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot delete from view \"%s\"",
RelationGetRelationName(resultRel)),
errhint("To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.")));
break;
default:
elog(ERROR, "unrecognized CmdType: %d", (int) operation);
break;
}
break;
case RELKIND_MATVIEW:
if (!MatViewIncrementalMaintenanceIsEnabled())
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot change materialized view \"%s\"",
RelationGetRelationName(resultRel))));
break;
case RELKIND_FOREIGN_TABLE:
/* Okay only if the FDW supports it */
fdwroutine = GetFdwRoutineForRelation(resultRel, false);
switch (operation)
{
case CMD_INSERT:
if (fdwroutine->ExecForeignInsert == NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot insert into foreign table \"%s\"",
RelationGetRelationName(resultRel))));
if (fdwroutine->IsForeignRelUpdatable != NULL &&
(fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_INSERT)) == 0)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("foreign table \"%s\" does not allow inserts",
RelationGetRelationName(resultRel))));
break;
case CMD_UPDATE:
if (fdwroutine->ExecForeignUpdate == NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot update foreign table \"%s\"",
RelationGetRelationName(resultRel))));
if (fdwroutine->IsForeignRelUpdatable != NULL &&
(fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_UPDATE)) == 0)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("foreign table \"%s\" does not allow updates",
RelationGetRelationName(resultRel))));
break;
case CMD_DELETE:
if (fdwroutine->ExecForeignDelete == NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot delete from foreign table \"%s\"",
RelationGetRelationName(resultRel))));
if (fdwroutine->IsForeignRelUpdatable != NULL &&
(fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_DELETE)) == 0)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("foreign table \"%s\" does not allow deletes",
RelationGetRelationName(resultRel))));
break;
default:
elog(ERROR, "unrecognized CmdType: %d", (int) operation);
break;
}
break;
default:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot change relation \"%s\"",
RelationGetRelationName(resultRel))));
break;
}
}
/*
* Check that a proposed rowmark target relation is a legal target
*
* In most cases parser and/or planner should have noticed this already, but
* they don't cover all cases.
*/
static void
CheckValidRowMarkRel(Relation rel, RowMarkType markType)
{
FdwRoutine *fdwroutine;
switch (rel->rd_rel->relkind)
{
case RELKIND_RELATION:
case RELKIND_PARTITIONED_TABLE:
/* OK */
break;
case RELKIND_SEQUENCE:
/* Must disallow this because we don't vacuum sequences */
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot lock rows in sequence \"%s\"",
RelationGetRelationName(rel))));
break;
case RELKIND_TOASTVALUE:
/* We could allow this, but there seems no good reason to */
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot lock rows in TOAST relation \"%s\"",
RelationGetRelationName(rel))));
break;
case RELKIND_VIEW:
/* Should not get here; planner should have expanded the view */
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot lock rows in view \"%s\"",
RelationGetRelationName(rel))));
break;
case RELKIND_MATVIEW:
/* Allow referencing a matview, but not actual locking clauses */
if (markType != ROW_MARK_REFERENCE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot lock rows in materialized view \"%s\"",
RelationGetRelationName(rel))));
break;
case RELKIND_FOREIGN_TABLE:
/* Okay only if the FDW supports it */
fdwroutine = GetFdwRoutineForRelation(rel, false);
if (fdwroutine->RefetchForeignRow == NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot lock rows in foreign table \"%s\"",
RelationGetRelationName(rel))));
break;
default:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot lock rows in relation \"%s\"",
RelationGetRelationName(rel))));
break;
}
}
/*
* Initialize ResultRelInfo data for one result relation
*
* Caution: before Postgres 9.1, this function included the relkind checking
* that's now in CheckValidResultRel, and it also did ExecOpenIndices if
* appropriate. Be sure callers cover those needs.
*/
void
InitResultRelInfo(ResultRelInfo *resultRelInfo,
Relation resultRelationDesc,
Index resultRelationIndex,
Relation partition_root,
int instrument_options)
{
List *partition_check = NIL;
MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
resultRelInfo->type = T_ResultRelInfo;
resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
resultRelInfo->ri_RelationDesc = resultRelationDesc;
resultRelInfo->ri_NumIndices = 0;
resultRelInfo->ri_IndexRelationDescs = NULL;
resultRelInfo->ri_IndexRelationInfo = NULL;
/* make a copy so as not to depend on relcache info not changing... */
resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
if (resultRelInfo->ri_TrigDesc)
{
int n = resultRelInfo->ri_TrigDesc->numtriggers;
resultRelInfo->ri_TrigFunctions = (FmgrInfo *)
palloc0(n * sizeof(FmgrInfo));
resultRelInfo->ri_TrigWhenExprs = (ExprState **)
palloc0(n * sizeof(ExprState *));
if (instrument_options)
resultRelInfo->ri_TrigInstrument = InstrAlloc(n, instrument_options);
}
else
{
resultRelInfo->ri_TrigFunctions = NULL;
resultRelInfo->ri_TrigWhenExprs = NULL;
resultRelInfo->ri_TrigInstrument = NULL;
}
if (resultRelationDesc->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
resultRelInfo->ri_FdwRoutine = GetFdwRoutineForRelation(resultRelationDesc, true);
else
resultRelInfo->ri_FdwRoutine = NULL;
resultRelInfo->ri_FdwState = NULL;
resultRelInfo->ri_usesFdwDirectModify = false;
resultRelInfo->ri_ConstraintExprs = NULL;
resultRelInfo->ri_junkFilter = NULL;
resultRelInfo->ri_projectReturning = NULL;
/*
* Partition constraint, which also includes the partition constraint of
* all the ancestors that are partitions. Note that it will be checked
* even in the case of tuple-routing where this table is the target leaf
* partition, if there any BR triggers defined on the table. Although
* tuple-routing implicitly preserves the partition constraint of the
* target partition for a given row, the BR triggers may change the row
* such that the constraint is no longer satisfied, which we must fail for
* by checking it explicitly.
*
* If this is a partitioned table, the partition constraint (if any) of a
* given row will be checked just before performing tuple-routing.
*/
partition_check = RelationGetPartitionQual(resultRelationDesc);
resultRelInfo->ri_PartitionCheck = partition_check;
resultRelInfo->ri_PartitionRoot = partition_root;
}
/*
* ExecGetTriggerResultRel
*
* Get a ResultRelInfo for a trigger target relation. Most of the time,
* triggers are fired on one of the result relations of the query, and so
* we can just return a member of the es_result_relations array. (Note: in
* self-join situations there might be multiple members with the same OID;
* if so it doesn't matter which one we pick.) However, it is sometimes
* necessary to fire triggers on other relations; this happens mainly when an
* RI update trigger queues additional triggers on other relations, which will
* be processed in the context of the outer query. For efficiency's sake,
* we want to have a ResultRelInfo for those triggers too; that can avoid
* repeated re-opening of the relation. (It also provides a way for EXPLAIN
* ANALYZE to report the runtimes of such triggers.) So we make additional
* ResultRelInfo's as needed, and save them in es_trig_target_relations.
*/
ResultRelInfo *
ExecGetTriggerResultRel(EState *estate, Oid relid)
{
ResultRelInfo *rInfo;
int nr;
ListCell *l;
Relation rel;
MemoryContext oldcontext;
/* First, search through the query result relations */
rInfo = estate->es_result_relations;
nr = estate->es_num_result_relations;
while (nr > 0)
{
if (RelationGetRelid(rInfo->ri_RelationDesc) == relid)
return rInfo;
rInfo++;
nr--;
}
/* Nope, but maybe we already made an extra ResultRelInfo for it */
foreach(l, estate->es_trig_target_relations)
{
rInfo = (ResultRelInfo *) lfirst(l);
if (RelationGetRelid(rInfo->ri_RelationDesc) == relid)
return rInfo;
}
/* Nope, so we need a new one */
/*
* Open the target relation's relcache entry. We assume that an
* appropriate lock is still held by the backend from whenever the trigger
* event got queued, so we need take no new lock here. Also, we need not
* recheck the relkind, so no need for CheckValidResultRel.
*/
rel = heap_open(relid, NoLock);
/*
* Make the new entry in the right context.
*/
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
rInfo = makeNode(ResultRelInfo);
InitResultRelInfo(rInfo,
rel,
0, /* dummy rangetable index */
NULL,
estate->es_instrument);
estate->es_trig_target_relations =
lappend(estate->es_trig_target_relations, rInfo);
MemoryContextSwitchTo(oldcontext);
/*
* Currently, we don't need any index information in ResultRelInfos used
* only for triggers, so no need to call ExecOpenIndices.
*/
return rInfo;
}
/*
* Close any relations that have been opened by ExecGetTriggerResultRel().
*/
void
ExecCleanUpTriggerState(EState *estate)
{
ListCell *l;
foreach(l, estate->es_trig_target_relations)
{
ResultRelInfo *resultRelInfo = (ResultRelInfo *) lfirst(l);
/* Close indices and then the relation itself */
ExecCloseIndices(resultRelInfo);
heap_close(resultRelInfo->ri_RelationDesc, NoLock);
}
}
/*
* ExecContextForcesOids
*
* This is pretty grotty: when doing INSERT, UPDATE, or CREATE TABLE AS,
* we need to ensure that result tuples have space for an OID iff they are
* going to be stored into a relation that has OIDs. In other contexts
* we are free to choose whether to leave space for OIDs in result tuples
* (we generally don't want to, but we do if a physical-tlist optimization
* is possible). This routine checks the plan context and returns TRUE if the
* choice is forced, FALSE if the choice is not forced. In the TRUE case,
* *hasoids is set to the required value.
*
* One reason this is ugly is that all plan nodes in the plan tree will emit
* tuples with space for an OID, though we really only need the topmost node
* to do so. However, node types like Sort don't project new tuples but just
* return their inputs, and in those cases the requirement propagates down
* to the input node. Eventually we might make this code smart enough to
* recognize how far down the requirement really goes, but for now we just
* make all plan nodes do the same thing if the top level forces the choice.
*
* We assume that if we are generating tuples for INSERT or UPDATE,
* estate->es_result_relation_info is already set up to describe the target
* relation. Note that in an UPDATE that spans an inheritance tree, some of
* the target relations may have OIDs and some not. We have to make the
* decisions on a per-relation basis as we initialize each of the subplans of
* the ModifyTable node, so ModifyTable has to set es_result_relation_info
* while initializing each subplan.
*
* CREATE TABLE AS is even uglier, because we don't have the target relation's
* descriptor available when this code runs; we have to look aside at the
* flags passed to ExecutorStart().
*/
bool
ExecContextForcesOids(PlanState *planstate, bool *hasoids)
{
ResultRelInfo *ri = planstate->state->es_result_relation_info;
if (ri != NULL)
{
Relation rel = ri->ri_RelationDesc;
if (rel != NULL)
{
*hasoids = rel->rd_rel->relhasoids;
return true;
}
}
if (planstate->state->es_top_eflags & EXEC_FLAG_WITH_OIDS)
{
*hasoids = true;
return true;
}
if (planstate->state->es_top_eflags & EXEC_FLAG_WITHOUT_OIDS)
{
*hasoids = false;
return true;
}
return false;
}
/* ----------------------------------------------------------------
* ExecPostprocessPlan
*
* Give plan nodes a final chance to execute before shutdown
* ----------------------------------------------------------------
*/
static void
ExecPostprocessPlan(EState *estate)
{
ListCell *lc;
/*
* Make sure nodes run forward.
*/
estate->es_direction = ForwardScanDirection;
/*
* Run any secondary ModifyTable nodes to completion, in case the main
* query did not fetch all rows from them. (We do this to ensure that
* such nodes have predictable results.)
*/
foreach(lc, estate->es_auxmodifytables)
{
PlanState *ps = (PlanState *) lfirst(lc);
for (;;)
{
TupleTableSlot *slot;
/* Reset the per-output-tuple exprcontext each time */
ResetPerTupleExprContext(estate);
slot = ExecProcNode(ps);
if (TupIsNull(slot))
break;
}
}
}
/* ----------------------------------------------------------------
* ExecEndPlan
*
* Cleans up the query plan -- closes files and frees up storage
*
* NOTE: we are no longer very worried about freeing storage per se
* in this code; FreeExecutorState should be guaranteed to release all
* memory that needs to be released. What we are worried about doing
* is closing relations and dropping buffer pins. Thus, for example,
* tuple tables must be cleared or dropped to ensure pins are released.
* ----------------------------------------------------------------
*/
static void
ExecEndPlan(PlanState *planstate, EState *estate)
{
ResultRelInfo *resultRelInfo;
int i;
ListCell *l;
/*
* shut down the node-type-specific query processing
*/
ExecEndNode(planstate);
/*
* for subplans too
*/
foreach(l, estate->es_subplanstates)
{
PlanState *subplanstate = (PlanState *) lfirst(l);
ExecEndNode(subplanstate);
}
/*
* destroy the executor's tuple table. Actually we only care about
* releasing buffer pins and tupdesc refcounts; there's no need to pfree
* the TupleTableSlots, since the containing memory context is about to go
* away anyway.
*/
ExecResetTupleTable(estate->es_tupleTable, false);
/*
* close the result relation(s) if any, but hold locks until xact commit.
*/
resultRelInfo = estate->es_result_relations;
for (i = estate->es_num_result_relations; i > 0; i--)
{
/* Close indices and then the relation itself */
ExecCloseIndices(resultRelInfo);
heap_close(resultRelInfo->ri_RelationDesc, NoLock);
resultRelInfo++;
}
/* Close the root target relation(s). */
resultRelInfo = estate->es_root_result_relations;
for (i = estate->es_num_root_result_relations; i > 0; i--)
{
heap_close(resultRelInfo->ri_RelationDesc, NoLock);
resultRelInfo++;
}
/* likewise close any trigger target relations */
ExecCleanUpTriggerState(estate);
/*
* close any relations selected FOR [KEY] UPDATE/SHARE, again keeping
* locks
*/
foreach(l, estate->es_rowMarks)
{
ExecRowMark *erm = (ExecRowMark *) lfirst(l);
if (erm->relation)
heap_close(erm->relation, NoLock);
}
}
/* ----------------------------------------------------------------
* ExecutePlan
*
* Processes the query plan until we have retrieved 'numberTuples' tuples,
* moving in the specified direction.
*
* Runs to completion if numberTuples is 0
*
* Note: the ctid attribute is a 'junk' attribute that is removed before the
* user can see it
* ----------------------------------------------------------------
*/
static void
ExecutePlan(EState *estate,
PlanState *planstate,
bool use_parallel_mode,
CmdType operation,
bool sendTuples,
uint64 numberTuples,
ScanDirection direction,
DestReceiver *dest,
bool execute_once)
{
TupleTableSlot *slot;
uint64 current_tuple_count;
/*
* initialize local variables
*/
current_tuple_count = 0;
/*
* Set the direction.
*/
estate->es_direction = direction;
/*
* If the plan might potentially be executed multiple times, we must force
* it to run without parallelism, because we might exit early. Also
* disable parallelism when writing into a relation, because no database
* changes are allowed in parallel mode.
*/
if (!execute_once || dest->mydest == DestIntoRel)
use_parallel_mode = false;
if (use_parallel_mode)
EnterParallelMode();
/*
* Loop until we've processed the proper number of tuples from the plan.
*/
for (;;)
{
/* Reset the per-output-tuple exprcontext */
ResetPerTupleExprContext(estate);
/*
* Execute the plan and obtain a tuple
*/
slot = ExecProcNode(planstate);
/*
* if the tuple is null, then we assume there is nothing more to
* process so we just end the loop...
*/
if (TupIsNull(slot))
{
/* Allow nodes to release or shut down resources. */
(void) ExecShutdownNode(planstate);
break;
}
/*
* If we have a junk filter, then project a new tuple with the junk
* removed.
*
* Store this new "clean" tuple in the junkfilter's resultSlot.
* (Formerly, we stored it back over the "dirty" tuple, which is WRONG
* because that tuple slot has the wrong descriptor.)
*/
if (estate->es_junkFilter != NULL)
slot = ExecFilterJunk(estate->es_junkFilter, slot);
/*
* If we are supposed to send the tuple somewhere, do so. (In
* practice, this is probably always the case at this point.)
*/
if (sendTuples)
{
/*
* If we are not able to send the tuple, we assume the destination
* has closed and no more tuples can be sent. If that's the case,
* end the loop.
*/
if (!((*dest->receiveSlot) (slot, dest)))
break;
}
/*
* Count tuples processed, if this is a SELECT. (For other operation
* types, the ModifyTable plan node must count the appropriate
* events.)
*/
if (operation == CMD_SELECT)
(estate->es_processed)++;
/*
* check our tuple count.. if we've processed the proper number then
* quit, else loop again and process more tuples. Zero numberTuples
* means no limit.
*/
current_tuple_count++;
if (numberTuples && numberTuples == current_tuple_count)
{
/* Allow nodes to release or shut down resources. */
(void) ExecShutdownNode(planstate);
break;
}
}
if (use_parallel_mode)
ExitParallelMode();
}
/*
* ExecRelCheck --- check that tuple meets constraints for result relation
*
* Returns NULL if OK, else name of failed check constraint
*/
static const char *
ExecRelCheck(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate)
{
Relation rel = resultRelInfo->ri_RelationDesc;
int ncheck = rel->rd_att->constr->num_check;
ConstrCheck *check = rel->rd_att->constr->check;
ExprContext *econtext;
MemoryContext oldContext;
int i;
/*
* If first time through for this result relation, build expression
* nodetrees for rel's constraint expressions. Keep them in the per-query
* memory context so they'll survive throughout the query.
*/
if (resultRelInfo->ri_ConstraintExprs == NULL)
{
oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
resultRelInfo->ri_ConstraintExprs =
(ExprState **) palloc(ncheck * sizeof(ExprState *));
for (i = 0; i < ncheck; i++)
{
Expr *checkconstr;
checkconstr = stringToNode(check[i].ccbin);
resultRelInfo->ri_ConstraintExprs[i] =
ExecPrepareExpr(checkconstr, estate);
}
MemoryContextSwitchTo(oldContext);
}
/*
* We will use the EState's per-tuple context for evaluating constraint
* expressions (creating it if it's not already there).
*/
econtext = GetPerTupleExprContext(estate);
/* Arrange for econtext's scan tuple to be the tuple under test */
econtext->ecxt_scantuple = slot;
/* And evaluate the constraints */
for (i = 0; i < ncheck; i++)
{
ExprState *checkconstr = resultRelInfo->ri_ConstraintExprs[i];
/*
* NOTE: SQL specifies that a NULL result from a constraint expression
* is not to be treated as a failure. Therefore, use ExecCheck not
* ExecQual.
*/
if (!ExecCheck(checkconstr, econtext))
return check[i].ccname;
}
/* NULL result means no error */
return NULL;
}
/*
* ExecPartitionCheck --- check that tuple meets the partition constraint.
*/
static void
ExecPartitionCheck(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
EState *estate)
{
Relation rel = resultRelInfo->ri_RelationDesc;
TupleDesc tupdesc = RelationGetDescr(rel);
Bitmapset *modifiedCols;
Bitmapset *insertedCols;
Bitmapset *updatedCols;
ExprContext *econtext;
/*
* If first time through, build expression state tree for the partition
* check expression. Keep it in the per-query memory context so they'll
* survive throughout the query.
*/
if (resultRelInfo->ri_PartitionCheckExpr == NULL)
{
List *qual = resultRelInfo->ri_PartitionCheck;
resultRelInfo->ri_PartitionCheckExpr = ExecPrepareCheck(qual, estate);
}
/*
* We will use the EState's per-tuple context for evaluating constraint
* expressions (creating it if it's not already there).
*/
econtext = GetPerTupleExprContext(estate);
/* Arrange for econtext's scan tuple to be the tuple under test */
econtext->ecxt_scantuple = slot;
/*
* As in case of the catalogued constraints, we treat a NULL result as
* success here, not a failure.
*/
if (!ExecCheck(resultRelInfo->ri_PartitionCheckExpr, econtext))
{
char *val_desc;
Relation orig_rel = rel;
/* See the comment above. */
if (resultRelInfo->ri_PartitionRoot)
{
HeapTuple tuple = ExecFetchSlotTuple(slot);
TupleDesc old_tupdesc = RelationGetDescr(rel);
TupleConversionMap *map;
rel = resultRelInfo->ri_PartitionRoot;
tupdesc = RelationGetDescr(rel);
/* a reverse map */
map = convert_tuples_by_name(old_tupdesc, tupdesc,
gettext_noop("could not convert row type"));
if (map != NULL)
{
tuple = do_convert_tuple(tuple, map);
ExecStoreTuple(tuple, slot, InvalidBuffer, false);
}
}
insertedCols = GetInsertedColumns(resultRelInfo, estate);
updatedCols = GetUpdatedColumns(resultRelInfo, estate);
modifiedCols = bms_union(insertedCols, updatedCols);
val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
slot,
tupdesc,
modifiedCols,
64);
ereport(ERROR,
(errcode(ERRCODE_CHECK_VIOLATION),
errmsg("new row for relation \"%s\" violates partition constraint",
RelationGetRelationName(orig_rel)),
val_desc ? errdetail("Failing row contains %s.", val_desc) : 0));
}
}
/*
* ExecConstraints - check constraints of the tuple in 'slot'
*
* This checks the traditional NOT NULL and check constraints, as well as
* the partition constraint, if any.
*
* Note: 'slot' contains the tuple to check the constraints of, which may
* have been converted from the original input tuple after tuple routing.
* 'resultRelInfo' is the original result relation, before tuple routing.
*/
void
ExecConstraints(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate)
{
Relation rel = resultRelInfo->ri_RelationDesc;
TupleDesc tupdesc = RelationGetDescr(rel);
TupleConstr *constr = tupdesc->constr;
Bitmapset *modifiedCols;
Bitmapset *insertedCols;
Bitmapset *updatedCols;
Assert(constr || resultRelInfo->ri_PartitionCheck);
if (constr && constr->has_not_null)
{
int natts = tupdesc->natts;
int attrChk;
for (attrChk = 1; attrChk <= natts; attrChk++)
{
if (tupdesc->attrs[attrChk - 1]->attnotnull &&
slot_attisnull(slot, attrChk))
{
char *val_desc;
Relation orig_rel = rel;
TupleDesc orig_tupdesc = RelationGetDescr(rel);
/*
* If the tuple has been routed, it's been converted to the
* partition's rowtype, which might differ from the root
* table's. We must convert it back to the root table's
* rowtype so that val_desc shown error message matches the
* input tuple.
*/
if (resultRelInfo->ri_PartitionRoot)
{
HeapTuple tuple = ExecFetchSlotTuple(slot);
TupleConversionMap *map;
rel = resultRelInfo->ri_PartitionRoot;
tupdesc = RelationGetDescr(rel);
/* a reverse map */
map = convert_tuples_by_name(orig_tupdesc, tupdesc,
gettext_noop("could not convert row type"));
if (map != NULL)
{
tuple = do_convert_tuple(tuple, map);
ExecStoreTuple(tuple, slot, InvalidBuffer, false);
}
}
insertedCols = GetInsertedColumns(resultRelInfo, estate);
updatedCols = GetUpdatedColumns(resultRelInfo, estate);
modifiedCols = bms_union(insertedCols, updatedCols);
val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
slot,
tupdesc,
modifiedCols,
64);
ereport(ERROR,
(errcode(ERRCODE_NOT_NULL_VIOLATION),
errmsg("null value in column \"%s\" violates not-null constraint",
NameStr(orig_tupdesc->attrs[attrChk - 1]->attname)),
val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
errtablecol(orig_rel, attrChk)));
}
}
}
if (constr && constr->num_check > 0)
{
const char *failed;
if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
{
char *val_desc;
Relation orig_rel = rel;
/* See the comment above. */
if (resultRelInfo->ri_PartitionRoot)
{
HeapTuple tuple = ExecFetchSlotTuple(slot);
TupleDesc old_tupdesc = RelationGetDescr(rel);
TupleConversionMap *map;
rel = resultRelInfo->ri_PartitionRoot;
tupdesc = RelationGetDescr(rel);
/* a reverse map */
map = convert_tuples_by_name(old_tupdesc, tupdesc,
gettext_noop("could not convert row type"));
if (map != NULL)
{
tuple = do_convert_tuple(tuple, map);
ExecStoreTuple(tuple, slot, InvalidBuffer, false);
}
}
insertedCols = GetInsertedColumns(resultRelInfo, estate);
updatedCols = GetUpdatedColumns(resultRelInfo, estate);
modifiedCols = bms_union(insertedCols, updatedCols);
val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
slot,
tupdesc,
modifiedCols,
64);
ereport(ERROR,
(errcode(ERRCODE_CHECK_VIOLATION),
errmsg("new row for relation \"%s\" violates check constraint \"%s\"",
RelationGetRelationName(orig_rel), failed),
val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
errtableconstraint(orig_rel, failed)));
}
}
if (resultRelInfo->ri_PartitionCheck)
ExecPartitionCheck(resultRelInfo, slot, estate);
}
/*
* ExecWithCheckOptions -- check that tuple satisfies any WITH CHECK OPTIONs
* of the specified kind.
*
* Note that this needs to be called multiple times to ensure that all kinds of
* WITH CHECK OPTIONs are handled (both those from views which have the WITH
* CHECK OPTION set and from row level security policies). See ExecInsert()
* and ExecUpdate().
*/
void
ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate)
{
Relation rel = resultRelInfo->ri_RelationDesc;
TupleDesc tupdesc = RelationGetDescr(rel);
ExprContext *econtext;
ListCell *l1,
*l2;
/*
* We will use the EState's per-tuple context for evaluating constraint
* expressions (creating it if it's not already there).
*/
econtext = GetPerTupleExprContext(estate);
/* Arrange for econtext's scan tuple to be the tuple under test */
econtext->ecxt_scantuple = slot;
/* Check each of the constraints */
forboth(l1, resultRelInfo->ri_WithCheckOptions,
l2, resultRelInfo->ri_WithCheckOptionExprs)
{
WithCheckOption *wco = (WithCheckOption *) lfirst(l1);
ExprState *wcoExpr = (ExprState *) lfirst(l2);
/*
* Skip any WCOs which are not the kind we are looking for at this
* time.
*/
if (wco->kind != kind)
continue;
/*
* WITH CHECK OPTION checks are intended to ensure that the new tuple
* is visible (in the case of a view) or that it passes the
* 'with-check' policy (in the case of row security). If the qual
* evaluates to NULL or FALSE, then the new tuple won't be included in
* the view or doesn't pass the 'with-check' policy for the table.
*/
if (!ExecQual(wcoExpr, econtext))
{
char *val_desc;
Bitmapset *modifiedCols;
Bitmapset *insertedCols;
Bitmapset *updatedCols;
switch (wco->kind)
{
/*
* For WITH CHECK OPTIONs coming from views, we might be
* able to provide the details on the row, depending on
* the permissions on the relation (that is, if the user
* could view it directly anyway). For RLS violations, we
* don't include the data since we don't know if the user
* should be able to view the tuple as as that depends on
* the USING policy.
*/
case WCO_VIEW_CHECK:
insertedCols = GetInsertedColumns(resultRelInfo, estate);
updatedCols = GetUpdatedColumns(resultRelInfo, estate);
modifiedCols = bms_union(insertedCols, updatedCols);
val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
slot,
tupdesc,
modifiedCols,
64);
ereport(ERROR,
(errcode(ERRCODE_WITH_CHECK_OPTION_VIOLATION),
errmsg("new row violates check option for view \"%s\"",
wco->relname),
val_desc ? errdetail("Failing row contains %s.",
val_desc) : 0));
break;
case WCO_RLS_INSERT_CHECK:
case WCO_RLS_UPDATE_CHECK:
if (wco->polname != NULL)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("new row violates row-level security policy \"%s\" for table \"%s\"",
wco->polname, wco->relname)));
else
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("new row violates row-level security policy for table \"%s\"",
wco->relname)));
break;
case WCO_RLS_CONFLICT_CHECK:
if (wco->polname != NULL)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("new row violates row-level security policy \"%s\" (USING expression) for table \"%s\"",
wco->polname, wco->relname)));
else
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("new row violates row-level security policy (USING expression) for table \"%s\"",
wco->relname)));
break;
default:
elog(ERROR, "unrecognized WCO kind: %u", wco->kind);
break;
}
}
}
}
/*
* ExecBuildSlotValueDescription -- construct a string representing a tuple
*
* This is intentionally very similar to BuildIndexValueDescription, but
* unlike that function, we truncate long field values (to at most maxfieldlen
* bytes). That seems necessary here since heap field values could be very
* long, whereas index entries typically aren't so wide.
*
* Also, unlike the case with index entries, we need to be prepared to ignore
* dropped columns. We used to use the slot's tuple descriptor to decode the
* data, but the slot's descriptor doesn't identify dropped columns, so we
* now need to be passed the relation's descriptor.
*
* Note that, like BuildIndexValueDescription, if the user does not have
* permission to view any of the columns involved, a NULL is returned. Unlike
* BuildIndexValueDescription, if the user has access to view a subset of the
* column involved, that subset will be returned with a key identifying which
* columns they are.
*/
static char *
ExecBuildSlotValueDescription(Oid reloid,
TupleTableSlot *slot,
TupleDesc tupdesc,
Bitmapset *modifiedCols,
int maxfieldlen)
{
StringInfoData buf;
StringInfoData collist;
bool write_comma = false;
bool write_comma_collist = false;
int i;
AclResult aclresult;
bool table_perm = false;
bool any_perm = false;
/*
* Check if RLS is enabled and should be active for the relation; if so,
* then don't return anything. Otherwise, go through normal permission
* checks.
*/
if (check_enable_rls(reloid, InvalidOid, true) == RLS_ENABLED)
return NULL;
initStringInfo(&buf);
appendStringInfoChar(&buf, '(');
/*
* Check if the user has permissions to see the row. Table-level SELECT
* allows access to all columns. If the user does not have table-level
* SELECT then we check each column and include those the user has SELECT
* rights on. Additionally, we always include columns the user provided
* data for.
*/
aclresult = pg_class_aclcheck(reloid, GetUserId(), ACL_SELECT);
if (aclresult != ACLCHECK_OK)
{
/* Set up the buffer for the column list */
initStringInfo(&collist);
appendStringInfoChar(&collist, '(');
}
else
table_perm = any_perm = true;
/* Make sure the tuple is fully deconstructed */
slot_getallattrs(slot);
for (i = 0; i < tupdesc->natts; i++)
{
bool column_perm = false;
char *val;
int vallen;
/* ignore dropped columns */
if (tupdesc->attrs[i]->attisdropped)
continue;
if (!table_perm)
{
/*
* No table-level SELECT, so need to make sure they either have
* SELECT rights on the column or that they have provided the data
* for the column. If not, omit this column from the error
* message.
*/
aclresult = pg_attribute_aclcheck(reloid, tupdesc->attrs[i]->attnum,
GetUserId(), ACL_SELECT);
if (bms_is_member(tupdesc->attrs[i]->attnum - FirstLowInvalidHeapAttributeNumber,
modifiedCols) || aclresult == ACLCHECK_OK)
{
column_perm = any_perm = true;
if (write_comma_collist)
appendStringInfoString(&collist, ", ");
else
write_comma_collist = true;
appendStringInfoString(&collist, NameStr(tupdesc->attrs[i]->attname));
}
}
if (table_perm || column_perm)
{
if (slot->tts_isnull[i])
val = "null";
else
{
Oid foutoid;
bool typisvarlena;
getTypeOutputInfo(tupdesc->attrs[i]->atttypid,
&foutoid, &typisvarlena);
val = OidOutputFunctionCall(foutoid, slot->tts_values[i]);
}
if (write_comma)
appendStringInfoString(&buf, ", ");
else
write_comma = true;
/* truncate if needed */
vallen = strlen(val);
if (vallen <= maxfieldlen)
appendStringInfoString(&buf, val);
else
{
vallen = pg_mbcliplen(val, vallen, maxfieldlen);
appendBinaryStringInfo(&buf, val, vallen);
appendStringInfoString(&buf, "...");
}
}
}
/* If we end up with zero columns being returned, then return NULL. */
if (!any_perm)
return NULL;
appendStringInfoChar(&buf, ')');
if (!table_perm)
{
appendStringInfoString(&collist, ") = ");
appendStringInfoString(&collist, buf.data);
return collist.data;
}
return buf.data;
}
/*
* ExecUpdateLockMode -- find the appropriate UPDATE tuple lock mode for a
* given ResultRelInfo
*/
LockTupleMode
ExecUpdateLockMode(EState *estate, ResultRelInfo *relinfo)
{
Bitmapset *keyCols;
Bitmapset *updatedCols;
/*
* Compute lock mode to use. If columns that are part of the key have not
* been modified, then we can use a weaker lock, allowing for better
* concurrency.
*/
updatedCols = GetUpdatedColumns(relinfo, estate);
keyCols = RelationGetIndexAttrBitmap(relinfo->ri_RelationDesc,
INDEX_ATTR_BITMAP_KEY);
if (bms_overlap(keyCols, updatedCols))
return LockTupleExclusive;
return LockTupleNoKeyExclusive;
}
/*
* ExecFindRowMark -- find the ExecRowMark struct for given rangetable index
*
* If no such struct, either return NULL or throw error depending on missing_ok
*/
ExecRowMark *
ExecFindRowMark(EState *estate, Index rti, bool missing_ok)
{
ListCell *lc;
foreach(lc, estate->es_rowMarks)
{
ExecRowMark *erm = (ExecRowMark *) lfirst(lc);
if (erm->rti == rti)
return erm;
}
if (!missing_ok)
elog(ERROR, "failed to find ExecRowMark for rangetable index %u", rti);
return NULL;
}
/*
* ExecBuildAuxRowMark -- create an ExecAuxRowMark struct
*
* Inputs are the underlying ExecRowMark struct and the targetlist of the
* input plan node (not planstate node!). We need the latter to find out
* the column numbers of the resjunk columns.
*/
ExecAuxRowMark *
ExecBuildAuxRowMark(ExecRowMark *erm, List *targetlist)
{
ExecAuxRowMark *aerm = (ExecAuxRowMark *) palloc0(sizeof(ExecAuxRowMark));
char resname[32];
aerm->rowmark = erm;
/* Look up the resjunk columns associated with this rowmark */
if (erm->markType != ROW_MARK_COPY)
{
/* need ctid for all methods other than COPY */
snprintf(resname, sizeof(resname), "ctid%u", erm->rowmarkId);
aerm->ctidAttNo = ExecFindJunkAttributeInTlist(targetlist,
resname);
if (!AttributeNumberIsValid(aerm->ctidAttNo))
elog(ERROR, "could not find junk %s column", resname);
}
else
{
/* need wholerow if COPY */
snprintf(resname, sizeof(resname), "wholerow%u", erm->rowmarkId);
aerm->wholeAttNo = ExecFindJunkAttributeInTlist(targetlist,
resname);
if (!AttributeNumberIsValid(aerm->wholeAttNo))
elog(ERROR, "could not find junk %s column", resname);
}
/* if child rel, need tableoid */
if (erm->rti != erm->prti)
{
snprintf(resname, sizeof(resname), "tableoid%u", erm->rowmarkId);
aerm->toidAttNo = ExecFindJunkAttributeInTlist(targetlist,
resname);
if (!AttributeNumberIsValid(aerm->toidAttNo))
elog(ERROR, "could not find junk %s column", resname);
}
return aerm;
}
/*
* EvalPlanQual logic --- recheck modified tuple(s) to see if we want to
* process the updated version under READ COMMITTED rules.
*
* See backend/executor/README for some info about how this works.
*/
/*
* Check a modified tuple to see if we want to process its updated version
* under READ COMMITTED rules.
*
* estate - outer executor state data
* epqstate - state for EvalPlanQual rechecking
* relation - table containing tuple
* rti - rangetable index of table containing tuple
* lockmode - requested tuple lock mode
* *tid - t_ctid from the outdated tuple (ie, next updated version)
* priorXmax - t_xmax from the outdated tuple
*
* *tid is also an output parameter: it's modified to hold the TID of the
* latest version of the tuple (note this may be changed even on failure)
*
* Returns a slot containing the new candidate update/delete tuple, or
* NULL if we determine we shouldn't process the row.
*
* Note: properly, lockmode should be declared as enum LockTupleMode,
* but we use "int" to avoid having to include heapam.h in executor.h.
*/
TupleTableSlot *
EvalPlanQual(EState *estate, EPQState *epqstate,
Relation relation, Index rti, int lockmode,
ItemPointer tid, TransactionId priorXmax)
{
TupleTableSlot *slot;
HeapTuple copyTuple;
Assert(rti > 0);
/*
* Get and lock the updated version of the row; if fail, return NULL.
*/
copyTuple = EvalPlanQualFetch(estate, relation, lockmode, LockWaitBlock,
tid, priorXmax);
if (copyTuple == NULL)
return NULL;
/*
* For UPDATE/DELETE we have to return tid of actual row we're executing
* PQ for.
*/
*tid = copyTuple->t_self;
/*
* Need to run a recheck subquery. Initialize or reinitialize EPQ state.
*/
EvalPlanQualBegin(epqstate, estate);
/*
* Free old test tuple, if any, and store new tuple where relation's scan
* node will see it
*/
EvalPlanQualSetTuple(epqstate, rti, copyTuple);
/*
* Fetch any non-locked source rows
*/
EvalPlanQualFetchRowMarks(epqstate);
/*
* Run the EPQ query. We assume it will return at most one tuple.
*/
slot = EvalPlanQualNext(epqstate);
/*
* If we got a tuple, force the slot to materialize the tuple so that it
* is not dependent on any local state in the EPQ query (in particular,
* it's highly likely that the slot contains references to any pass-by-ref
* datums that may be present in copyTuple). As with the next step, this
* is to guard against early re-use of the EPQ query.
*/
if (!TupIsNull(slot))
(void) ExecMaterializeSlot(slot);
/*
* Clear out the test tuple. This is needed in case the EPQ query is
* re-used to test a tuple for a different relation. (Not clear that can
* really happen, but let's be safe.)
*/
EvalPlanQualSetTuple(epqstate, rti, NULL);
return slot;
}
/*
* Fetch a copy of the newest version of an outdated tuple
*
* estate - executor state data
* relation - table containing tuple
* lockmode - requested tuple lock mode
* wait_policy - requested lock wait policy
* *tid - t_ctid from the outdated tuple (ie, next updated version)
* priorXmax - t_xmax from the outdated tuple
*
* Returns a palloc'd copy of the newest tuple version, or NULL if we find
* that there is no newest version (ie, the row was deleted not updated).
* We also return NULL if the tuple is locked and the wait policy is to skip
* such tuples.
*
* If successful, we have locked the newest tuple version, so caller does not
* need to worry about it changing anymore.
*
* Note: properly, lockmode should be declared as enum LockTupleMode,
* but we use "int" to avoid having to include heapam.h in executor.h.
*/
HeapTuple
EvalPlanQualFetch(EState *estate, Relation relation, int lockmode,
LockWaitPolicy wait_policy,
ItemPointer tid, TransactionId priorXmax)
{
HeapTuple copyTuple = NULL;
HeapTupleData tuple;
SnapshotData SnapshotDirty;
/*
* fetch target tuple
*
* Loop here to deal with updated or busy tuples
*/
InitDirtySnapshot(SnapshotDirty);
tuple.t_self = *tid;
for (;;)
{
Buffer buffer;
if (heap_fetch(relation, &SnapshotDirty, &tuple, &buffer, true, NULL))
{
HTSU_Result test;
HeapUpdateFailureData hufd;
/*
* If xmin isn't what we're expecting, the slot must have been
* recycled and reused for an unrelated tuple. This implies that
* the latest version of the row was deleted, so we need do
* nothing. (Should be safe to examine xmin without getting
* buffer's content lock. We assume reading a TransactionId to be
* atomic, and Xmin never changes in an existing tuple, except to
* invalid or frozen, and neither of those can match priorXmax.)
*/
if (!TransactionIdEquals(HeapTupleHeaderGetXmin(tuple.t_data),
priorXmax))
{
ReleaseBuffer(buffer);
return NULL;
}
/* otherwise xmin should not be dirty... */
if (TransactionIdIsValid(SnapshotDirty.xmin))
elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
/*
* If tuple is being updated by other transaction then we have to
* wait for its commit/abort, or die trying.
*/
if (TransactionIdIsValid(SnapshotDirty.xmax))
{
ReleaseBuffer(buffer);
switch (wait_policy)
{
case LockWaitBlock:
XactLockTableWait(SnapshotDirty.xmax,
relation, &tuple.t_self,
XLTW_FetchUpdated);
break;
case LockWaitSkip:
if (!ConditionalXactLockTableWait(SnapshotDirty.xmax))
return NULL; /* skip instead of waiting */
break;
case LockWaitError:
if (!ConditionalXactLockTableWait(SnapshotDirty.xmax))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
RelationGetRelationName(relation))));
break;
}
continue; /* loop back to repeat heap_fetch */
}
/*
* If tuple was inserted by our own transaction, we have to check
* cmin against es_output_cid: cmin >= current CID means our
* command cannot see the tuple, so we should ignore it. Otherwise
* heap_lock_tuple() will throw an error, and so would any later
* attempt to update or delete the tuple. (We need not check cmax
* because HeapTupleSatisfiesDirty will consider a tuple deleted
* by our transaction dead, regardless of cmax.) We just checked
* that priorXmax == xmin, so we can test that variable instead of
* doing HeapTupleHeaderGetXmin again.
*/
if (TransactionIdIsCurrentTransactionId(priorXmax) &&
HeapTupleHeaderGetCmin(tuple.t_data) >= estate->es_output_cid)
{
ReleaseBuffer(buffer);
return NULL;
}
/*
* This is a live tuple, so now try to lock it.
*/
test = heap_lock_tuple(relation, &tuple,
estate->es_output_cid,
lockmode, wait_policy,
false, &buffer, &hufd);
/* We now have two pins on the buffer, get rid of one */
ReleaseBuffer(buffer);
switch (test)
{
case HeapTupleSelfUpdated:
/*
* The target tuple was already updated or deleted by the
* current command, or by a later command in the current
* transaction. We *must* ignore the tuple in the former
* case, so as to avoid the "Halloween problem" of
* repeated update attempts. In the latter case it might
* be sensible to fetch the updated tuple instead, but
* doing so would require changing heap_update and
* heap_delete to not complain about updating "invisible"
* tuples, which seems pretty scary (heap_lock_tuple will
* not complain, but few callers expect
* HeapTupleInvisible, and we're not one of them). So for
* now, treat the tuple as deleted and do not process.
*/
ReleaseBuffer(buffer);
return NULL;
case HeapTupleMayBeUpdated:
/* successfully locked */
break;
case HeapTupleUpdated:
ReleaseBuffer(buffer);
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
/* Should not encounter speculative tuple on recheck */
Assert(!HeapTupleHeaderIsSpeculative(tuple.t_data));
if (!ItemPointerEquals(&hufd.ctid, &tuple.t_self))
{
/* it was updated, so look at the updated version */
tuple.t_self = hufd.ctid;
/* updated row should have xmin matching this xmax */
priorXmax = hufd.xmax;
continue;
}
/* tuple was deleted, so give up */
return NULL;
case HeapTupleWouldBlock:
ReleaseBuffer(buffer);
return NULL;
case HeapTupleInvisible:
elog(ERROR, "attempted to lock invisible tuple");
default:
ReleaseBuffer(buffer);
elog(ERROR, "unrecognized heap_lock_tuple status: %u",
test);
return NULL; /* keep compiler quiet */
}
/*
* We got tuple - now copy it for use by recheck query.
*/
copyTuple = heap_copytuple(&tuple);
ReleaseBuffer(buffer);
break;
}
/*
* If the referenced slot was actually empty, the latest version of
* the row must have been deleted, so we need do nothing.
*/
if (tuple.t_data == NULL)
{
ReleaseBuffer(buffer);
return NULL;
}
/*
* As above, if xmin isn't what we're expecting, do nothing.
*/
if (!TransactionIdEquals(HeapTupleHeaderGetXmin(tuple.t_data),
priorXmax))
{
ReleaseBuffer(buffer);
return NULL;
}
/*
* If we get here, the tuple was found but failed SnapshotDirty.
* Assuming the xmin is either a committed xact or our own xact (as it
* certainly should be if we're trying to modify the tuple), this must
* mean that the row was updated or deleted by either a committed xact
* or our own xact. If it was deleted, we can ignore it; if it was
* updated then chain up to the next version and repeat the whole
* process.
*
* As above, it should be safe to examine xmax and t_ctid without the
* buffer content lock, because they can't be changing.
*/
if (ItemPointerEquals(&tuple.t_self, &tuple.t_data->t_ctid))
{
/* deleted, so forget about it */
ReleaseBuffer(buffer);
return NULL;
}
/* updated, so look at the updated row */
tuple.t_self = tuple.t_data->t_ctid;
/* updated row should have xmin matching this xmax */
priorXmax = HeapTupleHeaderGetUpdateXid(tuple.t_data);
ReleaseBuffer(buffer);
/* loop back to fetch next in chain */
}
/*
* Return the copied tuple
*/
return copyTuple;
}
/*
* EvalPlanQualInit -- initialize during creation of a plan state node
* that might need to invoke EPQ processing.
*
* Note: subplan/auxrowmarks can be NULL/NIL if they will be set later
* with EvalPlanQualSetPlan.
*/
void
EvalPlanQualInit(EPQState *epqstate, EState *estate,
Plan *subplan, List *auxrowmarks, int epqParam)
{
/* Mark the EPQ state inactive */
epqstate->estate = NULL;
epqstate->planstate = NULL;
epqstate->origslot = NULL;
/* ... and remember data that EvalPlanQualBegin will need */
epqstate->plan = subplan;
epqstate->arowMarks = auxrowmarks;
epqstate->epqParam = epqParam;
}
/*
* EvalPlanQualSetPlan -- set or change subplan of an EPQState.
*
* We need this so that ModifyTable can deal with multiple subplans.
*/
void
EvalPlanQualSetPlan(EPQState *epqstate, Plan *subplan, List *auxrowmarks)
{
/* If we have a live EPQ query, shut it down */
EvalPlanQualEnd(epqstate);
/* And set/change the plan pointer */
epqstate->plan = subplan;
/* The rowmarks depend on the plan, too */
epqstate->arowMarks = auxrowmarks;
}
/*
* Install one test tuple into EPQ state, or clear test tuple if tuple == NULL
*
* NB: passed tuple must be palloc'd; it may get freed later
*/
void
EvalPlanQualSetTuple(EPQState *epqstate, Index rti, HeapTuple tuple)
{
EState *estate = epqstate->estate;
Assert(rti > 0);
/*
* free old test tuple, if any, and store new tuple where relation's scan
* node will see it
*/
if (estate->es_epqTuple[rti - 1] != NULL)
heap_freetuple(estate->es_epqTuple[rti - 1]);
estate->es_epqTuple[rti - 1] = tuple;
estate->es_epqTupleSet[rti - 1] = true;
}
/*
* Fetch back the current test tuple (if any) for the specified RTI
*/
HeapTuple
EvalPlanQualGetTuple(EPQState *epqstate, Index rti)
{
EState *estate = epqstate->estate;
Assert(rti > 0);
return estate->es_epqTuple[rti - 1];
}
/*
* Fetch the current row values for any non-locked relations that need
* to be scanned by an EvalPlanQual operation. origslot must have been set
* to contain the current result row (top-level row) that we need to recheck.
*/
void
EvalPlanQualFetchRowMarks(EPQState *epqstate)
{
ListCell *l;
Assert(epqstate->origslot != NULL);
foreach(l, epqstate->arowMarks)
{
ExecAuxRowMark *aerm = (ExecAuxRowMark *) lfirst(l);
ExecRowMark *erm = aerm->rowmark;
Datum datum;
bool isNull;
HeapTupleData tuple;
if (RowMarkRequiresRowShareLock(erm->markType))
elog(ERROR, "EvalPlanQual doesn't support locking rowmarks");
/* clear any leftover test tuple for this rel */
EvalPlanQualSetTuple(epqstate, erm->rti, NULL);
/* if child rel, must check whether it produced this row */
if (erm->rti != erm->prti)
{
Oid tableoid;
datum = ExecGetJunkAttribute(epqstate->origslot,
aerm->toidAttNo,
&isNull);
/* non-locked rels could be on the inside of outer joins */
if (isNull)
continue;
tableoid = DatumGetObjectId(datum);
Assert(OidIsValid(erm->relid));
if (tableoid != erm->relid)
{
/* this child is inactive right now */
continue;
}
}
if (erm->markType == ROW_MARK_REFERENCE)
{
HeapTuple copyTuple;
Assert(erm->relation != NULL);
/* fetch the tuple's ctid */
datum = ExecGetJunkAttribute(epqstate->origslot,
aerm->ctidAttNo,
&isNull);
/* non-locked rels could be on the inside of outer joins */
if (isNull)
continue;
/* fetch requests on foreign tables must be passed to their FDW */
if (erm->relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
{
FdwRoutine *fdwroutine;
bool updated = false;
fdwroutine = GetFdwRoutineForRelation(erm->relation, false);
/* this should have been checked already, but let's be safe */
if (fdwroutine->RefetchForeignRow == NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot lock rows in foreign table \"%s\"",
RelationGetRelationName(erm->relation))));
copyTuple = fdwroutine->RefetchForeignRow(epqstate->estate,
erm,
datum,
&updated);
if (copyTuple == NULL)
elog(ERROR, "failed to fetch tuple for EvalPlanQual recheck");
/*
* Ideally we'd insist on updated == false here, but that
* assumes that FDWs can track that exactly, which they might
* not be able to. So just ignore the flag.
*/
}
else
{
/* ordinary table, fetch the tuple */
Buffer buffer;
tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
if (!heap_fetch(erm->relation, SnapshotAny, &tuple, &buffer,
false, NULL))
elog(ERROR, "failed to fetch tuple for EvalPlanQual recheck");
/* successful, copy tuple */
copyTuple = heap_copytuple(&tuple);
ReleaseBuffer(buffer);
}
/* store tuple */
EvalPlanQualSetTuple(epqstate, erm->rti, copyTuple);
}
else
{
HeapTupleHeader td;
Assert(erm->markType == ROW_MARK_COPY);
/* fetch the whole-row Var for the relation */
datum = ExecGetJunkAttribute(epqstate->origslot,
aerm->wholeAttNo,
&isNull);
/* non-locked rels could be on the inside of outer joins */
if (isNull)
continue;
td = DatumGetHeapTupleHeader(datum);
/* build a temporary HeapTuple control structure */
tuple.t_len = HeapTupleHeaderGetDatumLength(td);
tuple.t_data = td;
/* relation might be a foreign table, if so provide tableoid */
tuple.t_tableOid = erm->relid;
/* also copy t_ctid in case there's valid data there */
tuple.t_self = td->t_ctid;
/* copy and store tuple */
EvalPlanQualSetTuple(epqstate, erm->rti,
heap_copytuple(&tuple));
}
}
}
/*
* Fetch the next row (if any) from EvalPlanQual testing
*
* (In practice, there should never be more than one row...)
*/
TupleTableSlot *
EvalPlanQualNext(EPQState *epqstate)
{
MemoryContext oldcontext;
TupleTableSlot *slot;
oldcontext = MemoryContextSwitchTo(epqstate->estate->es_query_cxt);
slot = ExecProcNode(epqstate->planstate);
MemoryContextSwitchTo(oldcontext);
return slot;
}
/*
* Initialize or reset an EvalPlanQual state tree
*/
void
EvalPlanQualBegin(EPQState *epqstate, EState *parentestate)
{
EState *estate = epqstate->estate;
if (estate == NULL)
{
/* First time through, so create a child EState */
EvalPlanQualStart(epqstate, parentestate, epqstate->plan);
}
else
{
/*
* We already have a suitable child EPQ tree, so just reset it.
*/
int rtsize = list_length(parentestate->es_range_table);
PlanState *planstate = epqstate->planstate;
MemSet(estate->es_epqScanDone, 0, rtsize * sizeof(bool));
/* Recopy current values of parent parameters */
if (parentestate->es_plannedstmt->nParamExec > 0)
{
int i = parentestate->es_plannedstmt->nParamExec;
while (--i >= 0)
{
/* copy value if any, but not execPlan link */
estate->es_param_exec_vals[i].value =
parentestate->es_param_exec_vals[i].value;
estate->es_param_exec_vals[i].isnull =
parentestate->es_param_exec_vals[i].isnull;
}
}
/*
* Mark child plan tree as needing rescan at all scan nodes. The
* first ExecProcNode will take care of actually doing the rescan.
*/
planstate->chgParam = bms_add_member(planstate->chgParam,
epqstate->epqParam);
}
}
/*
* Start execution of an EvalPlanQual plan tree.
*
* This is a cut-down version of ExecutorStart(): we copy some state from
* the top-level estate rather than initializing it fresh.
*/
static void
EvalPlanQualStart(EPQState *epqstate, EState *parentestate, Plan *planTree)
{
EState *estate;
int rtsize;
MemoryContext oldcontext;
ListCell *l;
rtsize = list_length(parentestate->es_range_table);
epqstate->estate = estate = CreateExecutorState();
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
/*
* Child EPQ EStates share the parent's copy of unchanging state such as
* the snapshot, rangetable, result-rel info, and external Param info.
* They need their own copies of local state, including a tuple table,
* es_param_exec_vals, etc.
*
* The ResultRelInfo array management is trickier than it looks. We
* create a fresh array for the child but copy all the content from the
* parent. This is because it's okay for the child to share any
* per-relation state the parent has already created --- but if the child
* sets up any ResultRelInfo fields, such as its own junkfilter, that
* state must *not* propagate back to the parent. (For one thing, the
* pointed-to data is in a memory context that won't last long enough.)
*/
estate->es_direction = ForwardScanDirection;
estate->es_snapshot = parentestate->es_snapshot;
estate->es_crosscheck_snapshot = parentestate->es_crosscheck_snapshot;
estate->es_range_table = parentestate->es_range_table;
estate->es_plannedstmt = parentestate->es_plannedstmt;
estate->es_junkFilter = parentestate->es_junkFilter;
estate->es_output_cid = parentestate->es_output_cid;
if (parentestate->es_num_result_relations > 0)
{
int numResultRelations = parentestate->es_num_result_relations;
ResultRelInfo *resultRelInfos;
resultRelInfos = (ResultRelInfo *)
palloc(numResultRelations * sizeof(ResultRelInfo));
memcpy(resultRelInfos, parentestate->es_result_relations,
numResultRelations * sizeof(ResultRelInfo));
estate->es_result_relations = resultRelInfos;
estate->es_num_result_relations = numResultRelations;
}
/* es_result_relation_info must NOT be copied */
/* es_trig_target_relations must NOT be copied */
estate->es_rowMarks = parentestate->es_rowMarks;
estate->es_top_eflags = parentestate->es_top_eflags;
estate->es_instrument = parentestate->es_instrument;
/* es_auxmodifytables must NOT be copied */
/*
* The external param list is simply shared from parent. The internal
* param workspace has to be local state, but we copy the initial values
* from the parent, so as to have access to any param values that were
* already set from other parts of the parent's plan tree.
*/
estate->es_param_list_info = parentestate->es_param_list_info;
if (parentestate->es_plannedstmt->nParamExec > 0)
{
int i = parentestate->es_plannedstmt->nParamExec;
estate->es_param_exec_vals = (ParamExecData *)
palloc0(i * sizeof(ParamExecData));
while (--i >= 0)
{
/* copy value if any, but not execPlan link */
estate->es_param_exec_vals[i].value =
parentestate->es_param_exec_vals[i].value;
estate->es_param_exec_vals[i].isnull =
parentestate->es_param_exec_vals[i].isnull;
}
}
/*
* Each EState must have its own es_epqScanDone state, but if we have
* nested EPQ checks they should share es_epqTuple arrays. This allows
* sub-rechecks to inherit the values being examined by an outer recheck.
*/
estate->es_epqScanDone = (bool *) palloc0(rtsize * sizeof(bool));
if (parentestate->es_epqTuple != NULL)
{
estate->es_epqTuple = parentestate->es_epqTuple;
estate->es_epqTupleSet = parentestate->es_epqTupleSet;
}
else
{
estate->es_epqTuple = (HeapTuple *)
palloc0(rtsize * sizeof(HeapTuple));
estate->es_epqTupleSet = (bool *)
palloc0(rtsize * sizeof(bool));
}
/*
* Each estate also has its own tuple table.
*/
estate->es_tupleTable = NIL;
/*
* Initialize private state information for each SubPlan. We must do this
* before running ExecInitNode on the main query tree, since
* ExecInitSubPlan expects to be able to find these entries. Some of the
* SubPlans might not be used in the part of the plan tree we intend to
* run, but since it's not easy to tell which, we just initialize them
* all.
*/
Assert(estate->es_subplanstates == NIL);
foreach(l, parentestate->es_plannedstmt->subplans)
{
Plan *subplan = (Plan *) lfirst(l);
PlanState *subplanstate;
subplanstate = ExecInitNode(subplan, estate, 0);
estate->es_subplanstates = lappend(estate->es_subplanstates,
subplanstate);
}
/*
* Initialize the private state information for all the nodes in the part
* of the plan tree we need to run. This opens files, allocates storage
* and leaves us ready to start processing tuples.
*/
epqstate->planstate = ExecInitNode(planTree, estate, 0);
MemoryContextSwitchTo(oldcontext);
}
/*
* EvalPlanQualEnd -- shut down at termination of parent plan state node,
* or if we are done with the current EPQ child.
*
* This is a cut-down version of ExecutorEnd(); basically we want to do most
* of the normal cleanup, but *not* close result relations (which we are
* just sharing from the outer query). We do, however, have to close any
* trigger target relations that got opened, since those are not shared.
* (There probably shouldn't be any of the latter, but just in case...)
*/
void
EvalPlanQualEnd(EPQState *epqstate)
{
EState *estate = epqstate->estate;
MemoryContext oldcontext;
ListCell *l;
if (estate == NULL)
return; /* idle, so nothing to do */
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
ExecEndNode(epqstate->planstate);
foreach(l, estate->es_subplanstates)
{
PlanState *subplanstate = (PlanState *) lfirst(l);
ExecEndNode(subplanstate);
}
/* throw away the per-estate tuple table */
ExecResetTupleTable(estate->es_tupleTable, false);
/* close any trigger target relations attached to this EState */
ExecCleanUpTriggerState(estate);
MemoryContextSwitchTo(oldcontext);
FreeExecutorState(estate);
/* Mark EPQState idle */
epqstate->estate = NULL;
epqstate->planstate = NULL;
epqstate->origslot = NULL;
}
/*
* ExecSetupPartitionTupleRouting - set up information needed during
* tuple routing for partitioned tables
*
* Output arguments:
* 'pd' receives an array of PartitionDispatch objects with one entry for
* every partitioned table in the partition tree
* 'partitions' receives an array of ResultRelInfo objects with one entry for
* every leaf partition in the partition tree
* 'tup_conv_maps' receives an array of TupleConversionMap objects with one
* entry for every leaf partition (required to convert input tuple based
* on the root table's rowtype to a leaf partition's rowtype after tuple
* routing is done
* 'partition_tuple_slot' receives a standalone TupleTableSlot to be used
* to manipulate any given leaf partition's rowtype after that partition
* is chosen by tuple-routing.
* 'num_parted' receives the number of partitioned tables in the partition
* tree (= the number of entries in the 'pd' output array)
* 'num_partitions' receives the number of leaf partitions in the partition
* tree (= the number of entries in the 'partitions' and 'tup_conv_maps'
* output arrays
*
* Note that all the relations in the partition tree are locked using the
* RowExclusiveLock mode upon return from this function.
*/
void
ExecSetupPartitionTupleRouting(Relation rel,
PartitionDispatch **pd,
ResultRelInfo **partitions,
TupleConversionMap ***tup_conv_maps,
TupleTableSlot **partition_tuple_slot,
int *num_parted, int *num_partitions)
{
TupleDesc tupDesc = RelationGetDescr(rel);
List *leaf_parts;
ListCell *cell;
int i;
ResultRelInfo *leaf_part_rri;
/* Get the tuple-routing information and lock partitions */
*pd = RelationGetPartitionDispatchInfo(rel, RowExclusiveLock, num_parted,
&leaf_parts);
*num_partitions = list_length(leaf_parts);
*partitions = (ResultRelInfo *) palloc(*num_partitions *
sizeof(ResultRelInfo));
*tup_conv_maps = (TupleConversionMap **) palloc0(*num_partitions *
sizeof(TupleConversionMap *));
/*
* Initialize an empty slot that will be used to manipulate tuples of any
* given partition's rowtype. It is attached to the caller-specified node
* (such as ModifyTableState) and released when the node finishes
* processing.
*/
*partition_tuple_slot = MakeTupleTableSlot();
leaf_part_rri = *partitions;
i = 0;
foreach(cell, leaf_parts)
{
Relation partrel;
TupleDesc part_tupdesc;
/*
* We locked all the partitions above including the leaf partitions.
* Note that each of the relations in *partitions are eventually
* closed by the caller.
*/
partrel = heap_open(lfirst_oid(cell), NoLock);
part_tupdesc = RelationGetDescr(partrel);
/*
* Verify result relation is a valid target for the current operation.
*/
CheckValidResultRel(partrel, CMD_INSERT);
/*
* Save a tuple conversion map to convert a tuple routed to this
* partition from the parent's type to the partition's.
*/
(*tup_conv_maps)[i] = convert_tuples_by_name(tupDesc, part_tupdesc,
gettext_noop("could not convert row type"));
InitResultRelInfo(leaf_part_rri,
partrel,
1, /* dummy */
rel,
0);
/*
* Open partition indices (remember we do not support ON CONFLICT in
* case of partitioned tables, so we do not need support information
* for speculative insertion)
*/
if (leaf_part_rri->ri_RelationDesc->rd_rel->relhasindex &&
leaf_part_rri->ri_IndexRelationDescs == NULL)
ExecOpenIndices(leaf_part_rri, false);
leaf_part_rri++;
i++;
}
}
/*
* ExecFindPartition -- Find a leaf partition in the partition tree rooted
* at parent, for the heap tuple contained in *slot
*
* estate must be non-NULL; we'll need it to compute any expressions in the
* partition key(s)
*
* If no leaf partition is found, this routine errors out with the appropriate
* error message, else it returns the leaf partition sequence number returned
* by get_partition_for_tuple() unchanged.
*/
int
ExecFindPartition(ResultRelInfo *resultRelInfo, PartitionDispatch *pd,
TupleTableSlot *slot, EState *estate)
{
int result;
PartitionDispatchData *failed_at;
TupleTableSlot *failed_slot;
/*
* First check the root table's partition constraint, if any. No point in
* routing the tuple it if it doesn't belong in the root table itself.
*/
if (resultRelInfo->ri_PartitionCheck)
ExecPartitionCheck(resultRelInfo, slot, estate);
result = get_partition_for_tuple(pd, slot, estate,
&failed_at, &failed_slot);
if (result < 0)
{
Relation failed_rel;
Datum key_values[PARTITION_MAX_KEYS];
bool key_isnull[PARTITION_MAX_KEYS];
char *val_desc;
ExprContext *ecxt = GetPerTupleExprContext(estate);
failed_rel = failed_at->reldesc;
ecxt->ecxt_scantuple = failed_slot;
FormPartitionKeyDatum(failed_at, failed_slot, estate,
key_values, key_isnull);
val_desc = ExecBuildSlotPartitionKeyDescription(failed_rel,
key_values,
key_isnull,
64);
Assert(OidIsValid(RelationGetRelid(failed_rel)));
ereport(ERROR,
(errcode(ERRCODE_CHECK_VIOLATION),
errmsg("no partition of relation \"%s\" found for row",
RelationGetRelationName(failed_rel)),
val_desc ? errdetail("Partition key of the failing row contains %s.", val_desc) : 0));
}
return result;
}
/*
* BuildSlotPartitionKeyDescription
*
* This works very much like BuildIndexValueDescription() and is currently
* used for building error messages when ExecFindPartition() fails to find
* partition for a row.
*/
static char *
ExecBuildSlotPartitionKeyDescription(Relation rel,
Datum *values,
bool *isnull,
int maxfieldlen)
{
StringInfoData buf;
PartitionKey key = RelationGetPartitionKey(rel);
int partnatts = get_partition_natts(key);
int i;
Oid relid = RelationGetRelid(rel);
AclResult aclresult;
if (check_enable_rls(relid, InvalidOid, true) == RLS_ENABLED)
return NULL;
/* If the user has table-level access, just go build the description. */
aclresult = pg_class_aclcheck(relid, GetUserId(), ACL_SELECT);
if (aclresult != ACLCHECK_OK)
{
/*
* Step through the columns of the partition key and make sure the
* user has SELECT rights on all of them.
*/
for (i = 0; i < partnatts; i++)
{
AttrNumber attnum = get_partition_col_attnum(key, i);
/*
* If this partition key column is an expression, we return no
* detail rather than try to figure out what column(s) the
* expression includes and if the user has SELECT rights on them.
*/
if (attnum == InvalidAttrNumber ||
pg_attribute_aclcheck(relid, attnum, GetUserId(),
ACL_SELECT) != ACLCHECK_OK)
return NULL;
}
}
initStringInfo(&buf);
appendStringInfo(&buf, "(%s) = (",
pg_get_partkeydef_columns(relid, true));
for (i = 0; i < partnatts; i++)
{
char *val;
int vallen;
if (isnull[i])
val = "null";
else
{
Oid foutoid;
bool typisvarlena;
getTypeOutputInfo(get_partition_col_typid(key, i),
&foutoid, &typisvarlena);
val = OidOutputFunctionCall(foutoid, values[i]);
}
if (i > 0)
appendStringInfoString(&buf, ", ");
/* truncate if needed */
vallen = strlen(val);
if (vallen <= maxfieldlen)
appendStringInfoString(&buf, val);
else
{
vallen = pg_mbcliplen(val, vallen, maxfieldlen);
appendBinaryStringInfo(&buf, val, vallen);
appendStringInfoString(&buf, "...");
}
}
appendStringInfoChar(&buf, ')');
return buf.data;
}
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