/*-------------------------------------------------------------------------
*
* execUtils.c
* miscellaneous executor utility routines
*
* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/executor/execUtils.c
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* CreateExecutorState Create/delete executor working state
* FreeExecutorState
* CreateExprContext
* CreateStandaloneExprContext
* FreeExprContext
* ReScanExprContext
*
* ExecAssignExprContext Common code for plan node init routines.
* ExecAssignResultType
* etc
*
* ExecOpenScanRelation Common code for scan node init routines.
* ExecCloseScanRelation
*
* ExecOpenIndices \
* ExecCloseIndices | referenced by InitPlan, EndPlan,
* ExecInsertIndexTuples / ExecInsert, ExecUpdate
*
* RegisterExprContextCallback Register function shutdown callback
* UnregisterExprContextCallback Deregister function shutdown callback
*
* NOTES
* This file has traditionally been the place to stick misc.
* executor support stuff that doesn't really go anyplace else.
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/relscan.h"
#include "access/transam.h"
#include "catalog/index.h"
#include "executor/execdebug.h"
#include "nodes/nodeFuncs.h"
#include "parser/parsetree.h"
#include "storage/lmgr.h"
#include "utils/memutils.h"
#include "utils/relcache.h"
#include "utils/tqual.h"
static bool get_last_attnums(Node *node, ProjectionInfo *projInfo);
static bool index_recheck_constraint(Relation index, Oid *constr_procs,
Datum *existing_values, bool *existing_isnull,
Datum *new_values);
static void ShutdownExprContext(ExprContext *econtext, bool isCommit);
/* ----------------------------------------------------------------
* Executor state and memory management functions
* ----------------------------------------------------------------
*/
/* ----------------
* CreateExecutorState
*
* Create and initialize an EState node, which is the root of
* working storage for an entire Executor invocation.
*
* Principally, this creates the per-query memory context that will be
* used to hold all working data that lives till the end of the query.
* Note that the per-query context will become a child of the caller's
* CurrentMemoryContext.
* ----------------
*/
EState *
CreateExecutorState(void)
{
EState *estate;
MemoryContext qcontext;
MemoryContext oldcontext;
/*
* Create the per-query context for this Executor run.
*/
qcontext = AllocSetContextCreate(CurrentMemoryContext,
"ExecutorState",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/*
* Make the EState node within the per-query context. This way, we don't
* need a separate pfree() operation for it at shutdown.
*/
oldcontext = MemoryContextSwitchTo(qcontext);
estate = makeNode(EState);
/*
* Initialize all fields of the Executor State structure
*/
estate->es_direction = ForwardScanDirection;
estate->es_snapshot = SnapshotNow;
estate->es_crosscheck_snapshot = InvalidSnapshot; /* no crosscheck */
estate->es_range_table = NIL;
estate->es_plannedstmt = NULL;
estate->es_junkFilter = NULL;
estate->es_output_cid = (CommandId) 0;
estate->es_result_relations = NULL;
estate->es_num_result_relations = 0;
estate->es_result_relation_info = NULL;
estate->es_trig_target_relations = NIL;
estate->es_trig_tuple_slot = NULL;
estate->es_trig_oldtup_slot = NULL;
estate->es_param_list_info = NULL;
estate->es_param_exec_vals = NULL;
estate->es_query_cxt = qcontext;
estate->es_tupleTable = NIL;
estate->es_rowMarks = NIL;
estate->es_processed = 0;
estate->es_lastoid = InvalidOid;
estate->es_instrument = false;
estate->es_select_into = false;
estate->es_into_oids = false;
estate->es_exprcontexts = NIL;
estate->es_subplanstates = NIL;
estate->es_per_tuple_exprcontext = NULL;
estate->es_epqTuple = NULL;
estate->es_epqTupleSet = NULL;
estate->es_epqScanDone = NULL;
/*
* Return the executor state structure
*/
MemoryContextSwitchTo(oldcontext);
return estate;
}
/* ----------------
* FreeExecutorState
*
* Release an EState along with all remaining working storage.
*
* Note: this is not responsible for releasing non-memory resources,
* such as open relations or buffer pins. But it will shut down any
* still-active ExprContexts within the EState. That is sufficient
* cleanup for situations where the EState has only been used for expression
* evaluation, and not to run a complete Plan.
*
* This can be called in any memory context ... so long as it's not one
* of the ones to be freed.
* ----------------
*/
void
FreeExecutorState(EState *estate)
{
/*
* Shut down and free any remaining ExprContexts. We do this explicitly
* to ensure that any remaining shutdown callbacks get called (since they
* might need to release resources that aren't simply memory within the
* per-query memory context).
*/
while (estate->es_exprcontexts)
{
/*
* XXX: seems there ought to be a faster way to implement this than
* repeated list_delete(), no?
*/
FreeExprContext((ExprContext *) linitial(estate->es_exprcontexts),
true);
/* FreeExprContext removed the list link for us */
}
/*
* Free the per-query memory context, thereby releasing all working
* memory, including the EState node itself.
*/
MemoryContextDelete(estate->es_query_cxt);
}
/* ----------------
* CreateExprContext
*
* Create a context for expression evaluation within an EState.
*
* An executor run may require multiple ExprContexts (we usually make one
* for each Plan node, and a separate one for per-output-tuple processing
* such as constraint checking). Each ExprContext has its own "per-tuple"
* memory context.
*
* Note we make no assumption about the caller's memory context.
* ----------------
*/
ExprContext *
CreateExprContext(EState *estate)
{
ExprContext *econtext;
MemoryContext oldcontext;
/* Create the ExprContext node within the per-query memory context */
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
econtext = makeNode(ExprContext);
/* Initialize fields of ExprContext */
econtext->ecxt_scantuple = NULL;
econtext->ecxt_innertuple = NULL;
econtext->ecxt_outertuple = NULL;
econtext->ecxt_per_query_memory = estate->es_query_cxt;
/*
* Create working memory for expression evaluation in this context.
*/
econtext->ecxt_per_tuple_memory =
AllocSetContextCreate(estate->es_query_cxt,
"ExprContext",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
econtext->ecxt_param_exec_vals = estate->es_param_exec_vals;
econtext->ecxt_param_list_info = estate->es_param_list_info;
econtext->ecxt_aggvalues = NULL;
econtext->ecxt_aggnulls = NULL;
econtext->caseValue_datum = (Datum) 0;
econtext->caseValue_isNull = true;
econtext->domainValue_datum = (Datum) 0;
econtext->domainValue_isNull = true;
econtext->ecxt_estate = estate;
econtext->ecxt_callbacks = NULL;
/*
* Link the ExprContext into the EState to ensure it is shut down when the
* EState is freed. Because we use lcons(), shutdowns will occur in
* reverse order of creation, which may not be essential but can't hurt.
*/
estate->es_exprcontexts = lcons(econtext, estate->es_exprcontexts);
MemoryContextSwitchTo(oldcontext);
return econtext;
}
/* ----------------
* CreateStandaloneExprContext
*
* Create a context for standalone expression evaluation.
*
* An ExprContext made this way can be used for evaluation of expressions
* that contain no Params, subplans, or Var references (it might work to
* put tuple references into the scantuple field, but it seems unwise).
*
* The ExprContext struct is allocated in the caller's current memory
* context, which also becomes its "per query" context.
*
* It is caller's responsibility to free the ExprContext when done,
* or at least ensure that any shutdown callbacks have been called
* (ReScanExprContext() is suitable). Otherwise, non-memory resources
* might be leaked.
* ----------------
*/
ExprContext *
CreateStandaloneExprContext(void)
{
ExprContext *econtext;
/* Create the ExprContext node within the caller's memory context */
econtext = makeNode(ExprContext);
/* Initialize fields of ExprContext */
econtext->ecxt_scantuple = NULL;
econtext->ecxt_innertuple = NULL;
econtext->ecxt_outertuple = NULL;
econtext->ecxt_per_query_memory = CurrentMemoryContext;
/*
* Create working memory for expression evaluation in this context.
*/
econtext->ecxt_per_tuple_memory =
AllocSetContextCreate(CurrentMemoryContext,
"ExprContext",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
econtext->ecxt_param_exec_vals = NULL;
econtext->ecxt_param_list_info = NULL;
econtext->ecxt_aggvalues = NULL;
econtext->ecxt_aggnulls = NULL;
econtext->caseValue_datum = (Datum) 0;
econtext->caseValue_isNull = true;
econtext->domainValue_datum = (Datum) 0;
econtext->domainValue_isNull = true;
econtext->ecxt_estate = NULL;
econtext->ecxt_callbacks = NULL;
return econtext;
}
/* ----------------
* FreeExprContext
*
* Free an expression context, including calling any remaining
* shutdown callbacks.
*
* Since we free the temporary context used for expression evaluation,
* any previously computed pass-by-reference expression result will go away!
*
* If isCommit is false, we are being called in error cleanup, and should
* not call callbacks but only release memory. (It might be better to call
* the callbacks and pass the isCommit flag to them, but that would require
* more invasive code changes than currently seems justified.)
*
* Note we make no assumption about the caller's memory context.
* ----------------
*/
void
FreeExprContext(ExprContext *econtext, bool isCommit)
{
EState *estate;
/* Call any registered callbacks */
ShutdownExprContext(econtext, isCommit);
/* And clean up the memory used */
MemoryContextDelete(econtext->ecxt_per_tuple_memory);
/* Unlink self from owning EState, if any */
estate = econtext->ecxt_estate;
if (estate)
estate->es_exprcontexts = list_delete_ptr(estate->es_exprcontexts,
econtext);
/* And delete the ExprContext node */
pfree(econtext);
}
/*
* ReScanExprContext
*
* Reset an expression context in preparation for a rescan of its
* plan node. This requires calling any registered shutdown callbacks,
* since any partially complete set-returning-functions must be canceled.
*
* Note we make no assumption about the caller's memory context.
*/
void
ReScanExprContext(ExprContext *econtext)
{
/* Call any registered callbacks */
ShutdownExprContext(econtext, true);
/* And clean up the memory used */
MemoryContextReset(econtext->ecxt_per_tuple_memory);
}
/*
* Build a per-output-tuple ExprContext for an EState.
*
* This is normally invoked via GetPerTupleExprContext() macro,
* not directly.
*/
ExprContext *
MakePerTupleExprContext(EState *estate)
{
if (estate->es_per_tuple_exprcontext == NULL)
estate->es_per_tuple_exprcontext = CreateExprContext(estate);
return estate->es_per_tuple_exprcontext;
}
/* ----------------------------------------------------------------
* miscellaneous node-init support functions
*
* Note: all of these are expected to be called with CurrentMemoryContext
* equal to the per-query memory context.
* ----------------------------------------------------------------
*/
/* ----------------
* ExecAssignExprContext
*
* This initializes the ps_ExprContext field. It is only necessary
* to do this for nodes which use ExecQual or ExecProject
* because those routines require an econtext. Other nodes that
* don't have to evaluate expressions don't need to do this.
* ----------------
*/
void
ExecAssignExprContext(EState *estate, PlanState *planstate)
{
planstate->ps_ExprContext = CreateExprContext(estate);
}
/* ----------------
* ExecAssignResultType
* ----------------
*/
void
ExecAssignResultType(PlanState *planstate, TupleDesc tupDesc)
{
TupleTableSlot *slot = planstate->ps_ResultTupleSlot;
ExecSetSlotDescriptor(slot, tupDesc);
}
/* ----------------
* ExecAssignResultTypeFromTL
* ----------------
*/
void
ExecAssignResultTypeFromTL(PlanState *planstate)
{
bool hasoid;
TupleDesc tupDesc;
if (ExecContextForcesOids(planstate, &hasoid))
{
/* context forces OID choice; hasoid is now set correctly */
}
else
{
/* given free choice, don't leave space for OIDs in result tuples */
hasoid = false;
}
/*
* ExecTypeFromTL needs the parse-time representation of the tlist, not a
* list of ExprStates. This is good because some plan nodes don't bother
* to set up planstate->targetlist ...
*/
tupDesc = ExecTypeFromTL(planstate->plan->targetlist, hasoid);
ExecAssignResultType(planstate, tupDesc);
}
/* ----------------
* ExecGetResultType
* ----------------
*/
TupleDesc
ExecGetResultType(PlanState *planstate)
{
TupleTableSlot *slot = planstate->ps_ResultTupleSlot;
return slot->tts_tupleDescriptor;
}
/* ----------------
* ExecBuildProjectionInfo
*
* Build a ProjectionInfo node for evaluating the given tlist in the given
* econtext, and storing the result into the tuple slot. (Caller must have
* ensured that tuple slot has a descriptor matching the tlist!) Note that
* the given tlist should be a list of ExprState nodes, not Expr nodes.
*
* inputDesc can be NULL, but if it is not, we check to see whether simple
* Vars in the tlist match the descriptor. It is important to provide
* inputDesc for relation-scan plan nodes, as a cross check that the relation
* hasn't been changed since the plan was made. At higher levels of a plan,
* there is no need to recheck.
* ----------------
*/
ProjectionInfo *
ExecBuildProjectionInfo(List *targetList,
ExprContext *econtext,
TupleTableSlot *slot,
TupleDesc inputDesc)
{
ProjectionInfo *projInfo = makeNode(ProjectionInfo);
int len = ExecTargetListLength(targetList);
int *workspace;
int *varSlotOffsets;
int *varNumbers;
int *varOutputCols;
List *exprlist;
int numSimpleVars;
bool directMap;
ListCell *tl;
projInfo->pi_exprContext = econtext;
projInfo->pi_slot = slot;
/* since these are all int arrays, we need do just one palloc */
workspace = (int *) palloc(len * 3 * sizeof(int));
projInfo->pi_varSlotOffsets = varSlotOffsets = workspace;
projInfo->pi_varNumbers = varNumbers = workspace + len;
projInfo->pi_varOutputCols = varOutputCols = workspace + len * 2;
projInfo->pi_lastInnerVar = 0;
projInfo->pi_lastOuterVar = 0;
projInfo->pi_lastScanVar = 0;
/*
* We separate the target list elements into simple Var references and
* expressions which require the full ExecTargetList machinery. To be a
* simple Var, a Var has to be a user attribute and not mismatch the
* inputDesc. (Note: if there is a type mismatch then ExecEvalVar will
* probably throw an error at runtime, but we leave that to it.)
*/
exprlist = NIL;
numSimpleVars = 0;
directMap = true;
foreach(tl, targetList)
{
GenericExprState *gstate = (GenericExprState *) lfirst(tl);
Var *variable = (Var *) gstate->arg->expr;
bool isSimpleVar = false;
if (variable != NULL &&
IsA(variable, Var) &&
variable->varattno > 0)
{
if (!inputDesc)
isSimpleVar = true; /* can't check type, assume OK */
else if (variable->varattno <= inputDesc->natts)
{
Form_pg_attribute attr;
attr = inputDesc->attrs[variable->varattno - 1];
if (!attr->attisdropped && variable->vartype == attr->atttypid)
isSimpleVar = true;
}
}
if (isSimpleVar)
{
TargetEntry *tle = (TargetEntry *) gstate->xprstate.expr;
AttrNumber attnum = variable->varattno;
varNumbers[numSimpleVars] = attnum;
varOutputCols[numSimpleVars] = tle->resno;
if (tle->resno != numSimpleVars + 1)
directMap = false;
switch (variable->varno)
{
case INNER:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_innertuple);
if (projInfo->pi_lastInnerVar < attnum)
projInfo->pi_lastInnerVar = attnum;
break;
case OUTER:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_outertuple);
if (projInfo->pi_lastOuterVar < attnum)
projInfo->pi_lastOuterVar = attnum;
break;
default:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_scantuple);
if (projInfo->pi_lastScanVar < attnum)
projInfo->pi_lastScanVar = attnum;
break;
}
numSimpleVars++;
}
else
{
/* Not a simple variable, add it to generic targetlist */
exprlist = lappend(exprlist, gstate);
/* Examine expr to include contained Vars in lastXXXVar counts */
get_last_attnums((Node *) variable, projInfo);
}
}
projInfo->pi_targetlist = exprlist;
projInfo->pi_numSimpleVars = numSimpleVars;
projInfo->pi_directMap = directMap;
if (exprlist == NIL)
projInfo->pi_itemIsDone = NULL; /* not needed */
else
projInfo->pi_itemIsDone = (ExprDoneCond *)
palloc(len * sizeof(ExprDoneCond));
return projInfo;
}
/*
* get_last_attnums: expression walker for ExecBuildProjectionInfo
*
* Update the lastXXXVar counts to be at least as large as the largest
* attribute numbers found in the expression
*/
static bool
get_last_attnums(Node *node, ProjectionInfo *projInfo)
{
if (node == NULL)
return false;
if (IsA(node, Var))
{
Var *variable = (Var *) node;
AttrNumber attnum = variable->varattno;
switch (variable->varno)
{
case INNER:
if (projInfo->pi_lastInnerVar < attnum)
projInfo->pi_lastInnerVar = attnum;
break;
case OUTER:
if (projInfo->pi_lastOuterVar < attnum)
projInfo->pi_lastOuterVar = attnum;
break;
default:
if (projInfo->pi_lastScanVar < attnum)
projInfo->pi_lastScanVar = attnum;
break;
}
return false;
}
/*
* Don't examine the arguments of Aggrefs or WindowFuncs, because those do
* not represent expressions to be evaluated within the overall
* targetlist's econtext.
*/
if (IsA(node, Aggref))
return false;
if (IsA(node, WindowFunc))
return false;
return expression_tree_walker(node, get_last_attnums,
(void *) projInfo);
}
/* ----------------
* ExecAssignProjectionInfo
*
* forms the projection information from the node's targetlist
*
* Notes for inputDesc are same as for ExecBuildProjectionInfo: supply it
* for a relation-scan node, can pass NULL for upper-level nodes
* ----------------
*/
void
ExecAssignProjectionInfo(PlanState *planstate,
TupleDesc inputDesc)
{
planstate->ps_ProjInfo =
ExecBuildProjectionInfo(planstate->targetlist,
planstate->ps_ExprContext,
planstate->ps_ResultTupleSlot,
inputDesc);
}
/* ----------------
* ExecFreeExprContext
*
* A plan node's ExprContext should be freed explicitly during executor
* shutdown because there may be shutdown callbacks to call. (Other resources
* made by the above routines, such as projection info, don't need to be freed
* explicitly because they're just memory in the per-query memory context.)
*
* However ... there is no particular need to do it during ExecEndNode,
* because FreeExecutorState will free any remaining ExprContexts within
* the EState. Letting FreeExecutorState do it allows the ExprContexts to
* be freed in reverse order of creation, rather than order of creation as
* will happen if we delete them here, which saves O(N^2) work in the list
* cleanup inside FreeExprContext.
* ----------------
*/
void
ExecFreeExprContext(PlanState *planstate)
{
/*
* Per above discussion, don't actually delete the ExprContext. We do
* unlink it from the plan node, though.
*/
planstate->ps_ExprContext = NULL;
}
/* ----------------------------------------------------------------
* the following scan type support functions are for
* those nodes which are stubborn and return tuples in
* their Scan tuple slot instead of their Result tuple
* slot.. luck fur us, these nodes do not do projections
* so we don't have to worry about getting the ProjectionInfo
* right for them... -cim 6/3/91
* ----------------------------------------------------------------
*/
/* ----------------
* ExecGetScanType
* ----------------
*/
TupleDesc
ExecGetScanType(ScanState *scanstate)
{
TupleTableSlot *slot = scanstate->ss_ScanTupleSlot;
return slot->tts_tupleDescriptor;
}
/* ----------------
* ExecAssignScanType
* ----------------
*/
void
ExecAssignScanType(ScanState *scanstate, TupleDesc tupDesc)
{
TupleTableSlot *slot = scanstate->ss_ScanTupleSlot;
ExecSetSlotDescriptor(slot, tupDesc);
}
/* ----------------
* ExecAssignScanTypeFromOuterPlan
* ----------------
*/
void
ExecAssignScanTypeFromOuterPlan(ScanState *scanstate)
{
PlanState *outerPlan;
TupleDesc tupDesc;
outerPlan = outerPlanState(scanstate);
tupDesc = ExecGetResultType(outerPlan);
ExecAssignScanType(scanstate, tupDesc);
}
/* ----------------------------------------------------------------
* Scan node support
* ----------------------------------------------------------------
*/
/* ----------------------------------------------------------------
* ExecRelationIsTargetRelation
*
* Detect whether a relation (identified by rangetable index)
* is one of the target relations of the query.
* ----------------------------------------------------------------
*/
bool
ExecRelationIsTargetRelation(EState *estate, Index scanrelid)
{
ResultRelInfo *resultRelInfos;
int i;
resultRelInfos = estate->es_result_relations;
for (i = 0; i < estate->es_num_result_relations; i++)
{
if (resultRelInfos[i].ri_RangeTableIndex == scanrelid)
return true;
}
return false;
}
/* ----------------------------------------------------------------
* ExecOpenScanRelation
*
* Open the heap relation to be scanned by a base-level scan plan node.
* This should be called during the node's ExecInit routine.
*
* By default, this acquires AccessShareLock on the relation. However,
* if the relation was already locked by InitPlan, we don't need to acquire
* any additional lock. This saves trips to the shared lock manager.
* ----------------------------------------------------------------
*/
Relation
ExecOpenScanRelation(EState *estate, Index scanrelid)
{
Oid reloid;
LOCKMODE lockmode;
/*
* Determine the lock type we need. First, scan to see if target relation
* is a result relation. If not, check if it's a FOR UPDATE/FOR SHARE
* relation. In either of those cases, we got the lock already.
*/
lockmode = AccessShareLock;
if (ExecRelationIsTargetRelation(estate, scanrelid))
lockmode = NoLock;
else
{
ListCell *l;
foreach(l, estate->es_rowMarks)
{
ExecRowMark *erm = lfirst(l);
if (erm->rti == scanrelid)
{
lockmode = NoLock;
break;
}
}
}
/* OK, open the relation and acquire lock as needed */
reloid = getrelid(scanrelid, estate->es_range_table);
return heap_open(reloid, lockmode);
}
/* ----------------------------------------------------------------
* ExecCloseScanRelation
*
* Close the heap relation scanned by a base-level scan plan node.
* This should be called during the node's ExecEnd routine.
*
* Currently, we do not release the lock acquired by ExecOpenScanRelation.
* This lock should be held till end of transaction. (There is a faction
* that considers this too much locking, however.)
*
* If we did want to release the lock, we'd have to repeat the logic in
* ExecOpenScanRelation in order to figure out what to release.
* ----------------------------------------------------------------
*/
void
ExecCloseScanRelation(Relation scanrel)
{
heap_close(scanrel, NoLock);
}
/* ----------------------------------------------------------------
* ExecInsertIndexTuples support
* ----------------------------------------------------------------
*/
/* ----------------------------------------------------------------
* ExecOpenIndices
*
* Find the indices associated with a result relation, open them,
* and save information about them in the result ResultRelInfo.
*
* At entry, caller has already opened and locked
* resultRelInfo->ri_RelationDesc.
* ----------------------------------------------------------------
*/
void
ExecOpenIndices(ResultRelInfo *resultRelInfo)
{
Relation resultRelation = resultRelInfo->ri_RelationDesc;
List *indexoidlist;
ListCell *l;
int len,
i;
RelationPtr relationDescs;
IndexInfo **indexInfoArray;
resultRelInfo->ri_NumIndices = 0;
/* fast path if no indexes */
if (!RelationGetForm(resultRelation)->relhasindex)
return;
/*
* Get cached list of index OIDs
*/
indexoidlist = RelationGetIndexList(resultRelation);
len = list_length(indexoidlist);
if (len == 0)
return;
/*
* allocate space for result arrays
*/
relationDescs = (RelationPtr) palloc(len * sizeof(Relation));
indexInfoArray = (IndexInfo **) palloc(len * sizeof(IndexInfo *));
resultRelInfo->ri_NumIndices = len;
resultRelInfo->ri_IndexRelationDescs = relationDescs;
resultRelInfo->ri_IndexRelationInfo = indexInfoArray;
/*
* For each index, open the index relation and save pg_index info. We
* acquire RowExclusiveLock, signifying we will update the index.
*/
i = 0;
foreach(l, indexoidlist)
{
Oid indexOid = lfirst_oid(l);
Relation indexDesc;
IndexInfo *ii;
indexDesc = index_open(indexOid, RowExclusiveLock);
/* extract index key information from the index's pg_index info */
ii = BuildIndexInfo(indexDesc);
relationDescs[i] = indexDesc;
indexInfoArray[i] = ii;
i++;
}
list_free(indexoidlist);
}
/* ----------------------------------------------------------------
* ExecCloseIndices
*
* Close the index relations stored in resultRelInfo
* ----------------------------------------------------------------
*/
void
ExecCloseIndices(ResultRelInfo *resultRelInfo)
{
int i;
int numIndices;
RelationPtr indexDescs;
numIndices = resultRelInfo->ri_NumIndices;
indexDescs = resultRelInfo->ri_IndexRelationDescs;
for (i = 0; i < numIndices; i++)
{
if (indexDescs[i] == NULL)
continue; /* shouldn't happen? */
/* Drop lock acquired by ExecOpenIndices */
index_close(indexDescs[i], RowExclusiveLock);
}
/*
* XXX should free indexInfo array here too? Currently we assume that
* such stuff will be cleaned up automatically in FreeExecutorState.
*/
}
/* ----------------------------------------------------------------
* ExecInsertIndexTuples
*
* This routine takes care of inserting index tuples
* into all the relations indexing the result relation
* when a heap tuple is inserted into the result relation.
* Much of this code should be moved into the genam
* stuff as it only exists here because the genam stuff
* doesn't provide the functionality needed by the
* executor.. -cim 9/27/89
*
* This returns a list of index OIDs for any unique or exclusion
* constraints that are deferred and that had
* potential (unconfirmed) conflicts.
*
* CAUTION: this must not be called for a HOT update.
* We can't defend against that here for lack of info.
* Should we change the API to make it safer?
* ----------------------------------------------------------------
*/
List *
ExecInsertIndexTuples(TupleTableSlot *slot,
ItemPointer tupleid,
EState *estate)
{
List *result = NIL;
ResultRelInfo *resultRelInfo;
int i;
int numIndices;
RelationPtr relationDescs;
Relation heapRelation;
IndexInfo **indexInfoArray;
ExprContext *econtext;
Datum values[INDEX_MAX_KEYS];
bool isnull[INDEX_MAX_KEYS];
/*
* Get information from the result relation info structure.
*/
resultRelInfo = estate->es_result_relation_info;
numIndices = resultRelInfo->ri_NumIndices;
relationDescs = resultRelInfo->ri_IndexRelationDescs;
indexInfoArray = resultRelInfo->ri_IndexRelationInfo;
heapRelation = resultRelInfo->ri_RelationDesc;
/*
* We will use the EState's per-tuple context for evaluating predicates
* and index 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;
/*
* for each index, form and insert the index tuple
*/
for (i = 0; i < numIndices; i++)
{
Relation indexRelation = relationDescs[i];
IndexInfo *indexInfo;
IndexUniqueCheck checkUnique;
bool satisfiesConstraint;
if (indexRelation == NULL)
continue;
indexInfo = indexInfoArray[i];
/* If the index is marked as read-only, ignore it */
if (!indexInfo->ii_ReadyForInserts)
continue;
/* Check for partial index */
if (indexInfo->ii_Predicate != NIL)
{
List *predicate;
/*
* If predicate state not set up yet, create it (in the estate's
* per-query context)
*/
predicate = indexInfo->ii_PredicateState;
if (predicate == NIL)
{
predicate = (List *)
ExecPrepareExpr((Expr *) indexInfo->ii_Predicate,
estate);
indexInfo->ii_PredicateState = predicate;
}
/* Skip this index-update if the predicate isn't satisfied */
if (!ExecQual(predicate, econtext, false))
continue;
}
/*
* FormIndexDatum fills in its values and isnull parameters with the
* appropriate values for the column(s) of the index.
*/
FormIndexDatum(indexInfo,
slot,
estate,
values,
isnull);
/*
* The index AM does the actual insertion, plus uniqueness checking.
*
* For an immediate-mode unique index, we just tell the index AM to
* throw error if not unique.
*
* For a deferrable unique index, we tell the index AM to just detect
* possible non-uniqueness, and we add the index OID to the result
* list if further checking is needed.
*/
if (!indexRelation->rd_index->indisunique)
checkUnique = UNIQUE_CHECK_NO;
else if (indexRelation->rd_index->indimmediate)
checkUnique = UNIQUE_CHECK_YES;
else
checkUnique = UNIQUE_CHECK_PARTIAL;
satisfiesConstraint =
index_insert(indexRelation, /* index relation */
values, /* array of index Datums */
isnull, /* null flags */
tupleid, /* tid of heap tuple */
heapRelation, /* heap relation */
checkUnique); /* type of uniqueness check to do */
/*
* If the index has an associated exclusion constraint, check that.
* This is simpler than the process for uniqueness checks since we
* always insert first and then check. If the constraint is deferred,
* we check now anyway, but don't throw error on violation; instead
* we'll queue a recheck event.
*
* An index for an exclusion constraint can't also be UNIQUE (not an
* essential property, we just don't allow it in the grammar), so no
* need to preserve the prior state of satisfiesConstraint.
*/
if (indexInfo->ii_ExclusionOps != NULL)
{
bool errorOK = !indexRelation->rd_index->indimmediate;
satisfiesConstraint =
check_exclusion_constraint(heapRelation,
indexRelation, indexInfo,
tupleid, values, isnull,
estate, false, errorOK);
}
if ((checkUnique == UNIQUE_CHECK_PARTIAL ||
indexInfo->ii_ExclusionOps != NULL) &&
!satisfiesConstraint)
{
/*
* The tuple potentially violates the uniqueness or exclusion
* constraint, so make a note of the index so that we can re-check
* it later.
*/
result = lappend_oid(result, RelationGetRelid(indexRelation));
}
}
return result;
}
/*
* Check for violation of an exclusion constraint
*
* heap: the table containing the new tuple
* index: the index supporting the exclusion constraint
* indexInfo: info about the index, including the exclusion properties
* tupleid: heap TID of the new tuple we have just inserted
* values, isnull: the *index* column values computed for the new tuple
* estate: an EState we can do evaluation in
* newIndex: if true, we are trying to build a new index (this affects
* only the wording of error messages)
* errorOK: if true, don't throw error for violation
*
* Returns true if OK, false if actual or potential violation
*
* When errorOK is true, we report violation without waiting to see if any
* concurrent transaction has committed or not; so the violation is only
* potential, and the caller must recheck sometime later. This behavior
* is convenient for deferred exclusion checks; we need not bother queuing
* a deferred event if there is definitely no conflict at insertion time.
*
* When errorOK is false, we'll throw error on violation, so a false result
* is impossible.
*/
bool
check_exclusion_constraint(Relation heap, Relation index, IndexInfo *indexInfo,
ItemPointer tupleid, Datum *values, bool *isnull,
EState *estate, bool newIndex, bool errorOK)
{
Oid *constr_procs = indexInfo->ii_ExclusionProcs;
uint16 *constr_strats = indexInfo->ii_ExclusionStrats;
int index_natts = index->rd_index->indnatts;
IndexScanDesc index_scan;
HeapTuple tup;
ScanKeyData scankeys[INDEX_MAX_KEYS];
SnapshotData DirtySnapshot;
int i;
bool conflict;
bool found_self;
ExprContext *econtext;
TupleTableSlot *existing_slot;
TupleTableSlot *save_scantuple;
/*
* If any of the input values are NULL, the constraint check is assumed to
* pass (i.e., we assume the operators are strict).
*/
for (i = 0; i < index_natts; i++)
{
if (isnull[i])
return true;
}
/*
* Search the tuples that are in the index for any violations, including
* tuples that aren't visible yet.
*/
InitDirtySnapshot(DirtySnapshot);
for (i = 0; i < index_natts; i++)
{
ScanKeyInit(&scankeys[i],
i + 1,
constr_strats[i],
constr_procs[i],
values[i]);
}
/*
* Need a TupleTableSlot to put existing tuples in.
*
* To use FormIndexDatum, we have to make the econtext's scantuple point
* to this slot. Be sure to save and restore caller's value for
* scantuple.
*/
existing_slot = MakeSingleTupleTableSlot(RelationGetDescr(heap));
econtext = GetPerTupleExprContext(estate);
save_scantuple = econtext->ecxt_scantuple;
econtext->ecxt_scantuple = existing_slot;
/*
* May have to restart scan from this point if a potential conflict is
* found.
*/
retry:
conflict = false;
found_self = false;
index_scan = index_beginscan(heap, index, &DirtySnapshot, index_natts, 0);
index_rescan(index_scan, scankeys, index_natts, NULL, 0);
while ((tup = index_getnext(index_scan,
ForwardScanDirection)) != NULL)
{
TransactionId xwait;
Datum existing_values[INDEX_MAX_KEYS];
bool existing_isnull[INDEX_MAX_KEYS];
char *error_new;
char *error_existing;
/*
* Ignore the entry for the tuple we're trying to check.
*/
if (ItemPointerEquals(tupleid, &tup->t_self))
{
if (found_self) /* should not happen */
elog(ERROR, "found self tuple multiple times in index \"%s\"",
RelationGetRelationName(index));
found_self = true;
continue;
}
/*
* Extract the index column values and isnull flags from the existing
* tuple.
*/
ExecStoreTuple(tup, existing_slot, InvalidBuffer, false);
FormIndexDatum(indexInfo, existing_slot, estate,
existing_values, existing_isnull);
/* If lossy indexscan, must recheck the condition */
if (index_scan->xs_recheck)
{
if (!index_recheck_constraint(index,
constr_procs,
existing_values,
existing_isnull,
values))
continue; /* tuple doesn't actually match, so no
* conflict */
}
/*
* At this point we have either a conflict or a potential conflict. If
* we're not supposed to raise error, just return the fact of the
* potential conflict without waiting to see if it's real.
*/
if (errorOK)
{
conflict = true;
break;
}
/*
* If an in-progress transaction is affecting the visibility of this
* tuple, we need to wait for it to complete and then recheck. For
* simplicity we do rechecking by just restarting the whole scan ---
* this case probably doesn't happen often enough to be worth trying
* harder, and anyway we don't want to hold any index internal locks
* while waiting.
*/
xwait = TransactionIdIsValid(DirtySnapshot.xmin) ?
DirtySnapshot.xmin : DirtySnapshot.xmax;
if (TransactionIdIsValid(xwait))
{
index_endscan(index_scan);
XactLockTableWait(xwait);
goto retry;
}
/*
* We have a definite conflict. Report it.
*/
error_new = BuildIndexValueDescription(index, values, isnull);
error_existing = BuildIndexValueDescription(index, existing_values,
existing_isnull);
if (newIndex)
ereport(ERROR,
(errcode(ERRCODE_EXCLUSION_VIOLATION),
errmsg("could not create exclusion constraint \"%s\"",
RelationGetRelationName(index)),
errdetail("Key %s conflicts with key %s.",
error_new, error_existing)));
else
ereport(ERROR,
(errcode(ERRCODE_EXCLUSION_VIOLATION),
errmsg("conflicting key value violates exclusion constraint \"%s\"",
RelationGetRelationName(index)),
errdetail("Key %s conflicts with existing key %s.",
error_new, error_existing)));
}
index_endscan(index_scan);
/*
* Ordinarily, at this point the search should have found the originally
* inserted tuple, unless we exited the loop early because of conflict.
* However, it is possible to define exclusion constraints for which
* that wouldn't be true --- for instance, if the operator is <>.
* So we no longer complain if found_self is still false.
*/
econtext->ecxt_scantuple = save_scantuple;
ExecDropSingleTupleTableSlot(existing_slot);
return !conflict;
}
/*
* Check existing tuple's index values to see if it really matches the
* exclusion condition against the new_values. Returns true if conflict.
*/
static bool
index_recheck_constraint(Relation index, Oid *constr_procs,
Datum *existing_values, bool *existing_isnull,
Datum *new_values)
{
int index_natts = index->rd_index->indnatts;
int i;
for (i = 0; i < index_natts; i++)
{
/* Assume the exclusion operators are strict */
if (existing_isnull[i])
return false;
if (!DatumGetBool(OidFunctionCall2(constr_procs[i],
existing_values[i],
new_values[i])))
return false;
}
return true;
}
/*
* UpdateChangedParamSet
* Add changed parameters to a plan node's chgParam set
*/
void
UpdateChangedParamSet(PlanState *node, Bitmapset *newchg)
{
Bitmapset *parmset;
/*
* The plan node only depends on params listed in its allParam set. Don't
* include anything else into its chgParam set.
*/
parmset = bms_intersect(node->plan->allParam, newchg);
/*
* Keep node->chgParam == NULL if there's not actually any members; this
* allows the simplest possible tests in executor node files.
*/
if (!bms_is_empty(parmset))
node->chgParam = bms_join(node->chgParam, parmset);
else
bms_free(parmset);
}
/*
* Register a shutdown callback in an ExprContext.
*
* Shutdown callbacks will be called (in reverse order of registration)
* when the ExprContext is deleted or rescanned. This provides a hook
* for functions called in the context to do any cleanup needed --- it's
* particularly useful for functions returning sets. Note that the
* callback will *not* be called in the event that execution is aborted
* by an error.
*/
void
RegisterExprContextCallback(ExprContext *econtext,
ExprContextCallbackFunction function,
Datum arg)
{
ExprContext_CB *ecxt_callback;
/* Save the info in appropriate memory context */
ecxt_callback = (ExprContext_CB *)
MemoryContextAlloc(econtext->ecxt_per_query_memory,
sizeof(ExprContext_CB));
ecxt_callback->function = function;
ecxt_callback->arg = arg;
/* link to front of list for appropriate execution order */
ecxt_callback->next = econtext->ecxt_callbacks;
econtext->ecxt_callbacks = ecxt_callback;
}
/*
* Deregister a shutdown callback in an ExprContext.
*
* Any list entries matching the function and arg will be removed.
* This can be used if it's no longer necessary to call the callback.
*/
void
UnregisterExprContextCallback(ExprContext *econtext,
ExprContextCallbackFunction function,
Datum arg)
{
ExprContext_CB **prev_callback;
ExprContext_CB *ecxt_callback;
prev_callback = &econtext->ecxt_callbacks;
while ((ecxt_callback = *prev_callback) != NULL)
{
if (ecxt_callback->function == function && ecxt_callback->arg == arg)
{
*prev_callback = ecxt_callback->next;
pfree(ecxt_callback);
}
else
prev_callback = &ecxt_callback->next;
}
}
/*
* Call all the shutdown callbacks registered in an ExprContext.
*
* The callback list is emptied (important in case this is only a rescan
* reset, and not deletion of the ExprContext).
*
* If isCommit is false, just clean the callback list but don't call 'em.
* (See comment for FreeExprContext.)
*/
static void
ShutdownExprContext(ExprContext *econtext, bool isCommit)
{
ExprContext_CB *ecxt_callback;
MemoryContext oldcontext;
/* Fast path in normal case where there's nothing to do. */
if (econtext->ecxt_callbacks == NULL)
return;
/*
* Call the callbacks in econtext's per-tuple context. This ensures that
* any memory they might leak will get cleaned up.
*/
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
/*
* Call each callback function in reverse registration order.
*/
while ((ecxt_callback = econtext->ecxt_callbacks) != NULL)
{
econtext->ecxt_callbacks = ecxt_callback->next;
if (isCommit)
(*ecxt_callback->function) (ecxt_callback->arg);
pfree(ecxt_callback);
}
MemoryContextSwitchTo(oldcontext);
}