/* ----------------------------------------------------------------
* ExecInitResult
*
* Creates the run-time state information for the result node
* produced by the planner and initializes outer relations
* (child nodes).
* ----------------------------------------------------------------
*/
ResultState *
ExecInitResult(Result *node, EState *estate, int eflags)
{
ResultState *resstate;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_MARK | EXEC_FLAG_BACKWARD)) ||
outerPlan(node) != NULL);
/*
* create state structure
*/
resstate = makeNode(ResultState);
resstate->ps.plan = (Plan *) node;
resstate->ps.state = estate;
resstate->ps.ExecProcNode = ExecResult;
resstate->rs_done = false;
resstate->rs_checkqual = (node->resconstantqual == NULL) ? false : true;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &resstate->ps);
/*
* initialize child nodes
*/
outerPlanState(resstate) = ExecInitNode(outerPlan(node), estate, eflags);
/*
* we don't use inner plan
*/
Assert(innerPlan(node) == NULL);
/*
* Initialize result slot, type and projection.
*/
ExecInitResultTupleSlotTL(&resstate->ps);
ExecAssignProjectionInfo(&resstate->ps, NULL);
/*
* initialize child expressions
*/
resstate->ps.qual =
ExecInitQual(node->plan.qual, (PlanState *) resstate);
resstate->resconstantqual =
ExecInitQual((List *) node->resconstantqual, (PlanState *) resstate);
return resstate;
}
/* -----------------
* ExecInitGroup
*
* Creates the run-time information for the group node produced by the
* planner and initializes its outer subtree
* -----------------
*/
GroupState *
ExecInitGroup(Group *node, EState *estate, int eflags)
{
GroupState *grpstate;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* create state structure
*/
grpstate = makeNode(GroupState);
grpstate->ss.ps.plan = (Plan *) node;
grpstate->ss.ps.state = estate;
grpstate->ss.ps.ExecProcNode = ExecGroup;
grpstate->grp_done = false;
/*
* create expression context
*/
ExecAssignExprContext(estate, &grpstate->ss.ps);
/*
* tuple table initialization
*/
ExecInitScanTupleSlot(estate, &grpstate->ss);
ExecInitResultTupleSlot(estate, &grpstate->ss.ps);
/*
* initialize child expressions
*/
grpstate->ss.ps.qual =
ExecInitQual(node->plan.qual, (PlanState *) grpstate);
/*
* initialize child nodes
*/
outerPlanState(grpstate) = ExecInitNode(outerPlan(node), estate, eflags);
/*
* initialize tuple type.
*/
ExecAssignScanTypeFromOuterPlan(&grpstate->ss);
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(&grpstate->ss.ps);
ExecAssignProjectionInfo(&grpstate->ss.ps, NULL);
/*
* Precompute fmgr lookup data for inner loop
*/
grpstate->eqfunctions =
execTuplesMatchPrepare(node->numCols,
node->grpOperators);
return grpstate;
}
/* ----------------------------------------------------------------
* ExecInitWorkTableScan
* ----------------------------------------------------------------
*/
WorkTableScanState *
ExecInitWorkTableScan(WorkTableScan *node, EState *estate, int eflags)
{
WorkTableScanState *scanstate;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* WorkTableScan should not have any children.
*/
Assert(outerPlan(node) == NULL);
Assert(innerPlan(node) == NULL);
/*
* create new WorkTableScanState for node
*/
scanstate = makeNode(WorkTableScanState);
scanstate->ss.ps.plan = (Plan *) node;
scanstate->ss.ps.state = estate;
scanstate->ss.ps.ExecProcNode = ExecWorkTableScan;
scanstate->rustate = NULL; /* we'll set this later */
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &scanstate->ss.ps);
/*
* tuple table initialization
*/
ExecInitResultTypeTL(&scanstate->ss.ps);
/* signal that return type is not yet known */
scanstate->ss.ps.resultopsset = true;
scanstate->ss.ps.resultopsfixed = false;
ExecInitScanTupleSlot(estate, &scanstate->ss, NULL, &TTSOpsMinimalTuple);
/*
* initialize child expressions
*/
scanstate->ss.ps.qual =
ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
/*
* Do not yet initialize projection info, see ExecWorkTableScan() for
* details.
*/
return scanstate;
}
/* ----------------------------------------------------------------
* ExecInitSeqScan
* ----------------------------------------------------------------
*/
SeqScanState *
ExecInitSeqScan(SeqScan *node, EState *estate, int eflags)
{
SeqScanState *scanstate;
/*
* Once upon a time it was possible to have an outerPlan of a SeqScan, but
* not any more.
*/
Assert(outerPlan(node) == NULL);
Assert(innerPlan(node) == NULL);
/*
* create state structure
*/
scanstate = makeNode(SeqScanState);
scanstate->ss.ps.plan = (Plan *) node;
scanstate->ss.ps.state = estate;
scanstate->ss.ps.ExecProcNode = ExecSeqScan;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &scanstate->ss.ps);
/*
* initialize child expressions
*/
scanstate->ss.ps.qual =
ExecInitQual(node->plan.qual, (PlanState *) scanstate);
/*
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
ExecInitScanTupleSlot(estate, &scanstate->ss);
/*
* initialize scan relation
*/
InitScanRelation(scanstate, estate, eflags);
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(&scanstate->ss.ps);
ExecAssignScanProjectionInfo(&scanstate->ss);
return scanstate;
}
/* ----------------------------------------------------------------
* ExecInitHash
*
* Init routine for Hash node
* ----------------------------------------------------------------
*/
HashState *
ExecInitHash(Hash *node, EState *estate, int eflags)
{
HashState *hashstate;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* create state structure
*/
hashstate = makeNode(HashState);
hashstate->ps.plan = (Plan *) node;
hashstate->ps.state = estate;
hashstate->ps.ExecProcNode = ExecHash;
hashstate->hashtable = NULL;
hashstate->hashkeys = NIL; /* will be set by parent HashJoin */
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &hashstate->ps);
/*
* initialize our result slot
*/
ExecInitResultTupleSlot(estate, &hashstate->ps);
/*
* initialize child expressions
*/
hashstate->ps.qual =
ExecInitQual(node->plan.qual, (PlanState *) hashstate);
/*
* initialize child nodes
*/
outerPlanState(hashstate) = ExecInitNode(outerPlan(node), estate, eflags);
/*
* initialize tuple type. no need to initialize projection info because
* this node doesn't do projections
*/
ExecAssignResultTypeFromTL(&hashstate->ps);
hashstate->ps.ps_ProjInfo = NULL;
return hashstate;
}
/* ----------------------------------------------------------------
* ExecInitIndexOnlyScan
*
* Initializes the index scan's state information, creates
* scan keys, and opens the base and index relations.
*
* Note: index scans have 2 sets of state information because
* we have to keep track of the base relation and the
* index relation.
* ----------------------------------------------------------------
*/
IndexOnlyScanState *
ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
{
IndexOnlyScanState *indexstate;
Relation currentRelation;
bool relistarget;
TupleDesc tupDesc;
/*
* create state structure
*/
indexstate = makeNode(IndexOnlyScanState);
indexstate->ss.ps.plan = (Plan *) node;
indexstate->ss.ps.state = estate;
indexstate->ss.ps.ExecProcNode = ExecIndexOnlyScan;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &indexstate->ss.ps);
/*
* open the scan relation
*/
currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
indexstate->ss.ss_currentRelation = currentRelation;
indexstate->ss.ss_currentScanDesc = NULL; /* no heap scan here */
/*
* Build the scan tuple type using the indextlist generated by the
* planner. We use this, rather than the index's physical tuple
* descriptor, because the latter contains storage column types not the
* types of the original datums. (It's the AM's responsibility to return
* suitable data anyway.)
*/
tupDesc = ExecTypeFromTL(node->indextlist);
ExecInitScanTupleSlot(estate, &indexstate->ss, tupDesc, &TTSOpsHeapTuple);
/*
* Initialize result type and projection info. The node's targetlist will
* contain Vars with varno = INDEX_VAR, referencing the scan tuple.
*/
ExecInitResultTypeTL(&indexstate->ss.ps);
ExecAssignScanProjectionInfoWithVarno(&indexstate->ss, INDEX_VAR);
/*
* initialize child expressions
*
* Note: we don't initialize all of the indexorderby expression, only the
* sub-parts corresponding to runtime keys (see below).
*/
indexstate->ss.ps.qual =
ExecInitQual(node->scan.plan.qual, (PlanState *) indexstate);
indexstate->indexqual =
ExecInitQual(node->indexqual, (PlanState *) indexstate);
/*
* If we are just doing EXPLAIN (ie, aren't going to run the plan), stop
* here. This allows an index-advisor plugin to EXPLAIN a plan containing
* references to nonexistent indexes.
*/
if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
return indexstate;
/*
* Open the index relation.
*
* If the parent table is one of the target relations of the query, then
* InitPlan already opened and write-locked the index, so we can avoid
* taking another lock here. Otherwise we need a normal reader's lock.
*/
relistarget = ExecRelationIsTargetRelation(estate, node->scan.scanrelid);
indexstate->ioss_RelationDesc = index_open(node->indexid,
relistarget ? NoLock : AccessShareLock);
/*
* Initialize index-specific scan state
*/
indexstate->ioss_RuntimeKeysReady = false;
indexstate->ioss_RuntimeKeys = NULL;
indexstate->ioss_NumRuntimeKeys = 0;
/*
* build the index scan keys from the index qualification
*/
ExecIndexBuildScanKeys((PlanState *) indexstate,
indexstate->ioss_RelationDesc,
node->indexqual,
false,
&indexstate->ioss_ScanKeys,
&indexstate->ioss_NumScanKeys,
&indexstate->ioss_RuntimeKeys,
&indexstate->ioss_NumRuntimeKeys,
NULL, /* no ArrayKeys */
NULL);
/*
* any ORDER BY exprs have to be turned into scankeys in the same way
*/
ExecIndexBuildScanKeys((PlanState *) indexstate,
indexstate->ioss_RelationDesc,
node->indexorderby,
true,
&indexstate->ioss_OrderByKeys,
&indexstate->ioss_NumOrderByKeys,
&indexstate->ioss_RuntimeKeys,
&indexstate->ioss_NumRuntimeKeys,
NULL, /* no ArrayKeys */
NULL);
/*
* If we have runtime keys, we need an ExprContext to evaluate them. The
* node's standard context won't do because we want to reset that context
* for every tuple. So, build another context just like the other one...
* -tgl 7/11/00
*/
if (indexstate->ioss_NumRuntimeKeys != 0)
{
ExprContext *stdecontext = indexstate->ss.ps.ps_ExprContext;
ExecAssignExprContext(estate, &indexstate->ss.ps);
indexstate->ioss_RuntimeContext = indexstate->ss.ps.ps_ExprContext;
indexstate->ss.ps.ps_ExprContext = stdecontext;
}
else
{
indexstate->ioss_RuntimeContext = NULL;
}
/*
* all done.
*/
return indexstate;
}
/* ----------------------------------------------------------------
* ExecInitCteScan
* ----------------------------------------------------------------
*/
CteScanState *
ExecInitCteScan(CteScan *node, EState *estate, int eflags)
{
CteScanState *scanstate;
ParamExecData *prmdata;
/* check for unsupported flags */
Assert(!(eflags & EXEC_FLAG_MARK));
/*
* For the moment we have to force the tuplestore to allow REWIND, because
* we might be asked to rescan the CTE even though upper levels didn't
* tell us to be prepared to do it efficiently. Annoying, since this
* prevents truncation of the tuplestore. XXX FIXME
*
* Note: if we are in an EPQ recheck plan tree, it's likely that no access
* to the tuplestore is needed at all, making this even more annoying.
* It's not worth improving that as long as all the read pointers would
* have REWIND anyway, but if we ever improve this logic then that aspect
* should be considered too.
*/
eflags |= EXEC_FLAG_REWIND;
/*
* CteScan should not have any children.
*/
Assert(outerPlan(node) == NULL);
Assert(innerPlan(node) == NULL);
/*
* create new CteScanState for node
*/
scanstate = makeNode(CteScanState);
scanstate->ss.ps.plan = (Plan *) node;
scanstate->ss.ps.state = estate;
scanstate->ss.ps.ExecProcNode = ExecCteScan;
scanstate->eflags = eflags;
scanstate->cte_table = NULL;
scanstate->eof_cte = false;
/*
* Find the already-initialized plan for the CTE query.
*/
scanstate->cteplanstate = (PlanState *) list_nth(estate->es_subplanstates,
node->ctePlanId - 1);
/*
* The Param slot associated with the CTE query is used to hold a pointer
* to the CteState of the first CteScan node that initializes for this
* CTE. This node will be the one that holds the shared state for all the
* CTEs, particularly the shared tuplestore.
*/
prmdata = &(estate->es_param_exec_vals[node->cteParam]);
Assert(prmdata->execPlan == NULL);
Assert(!prmdata->isnull);
scanstate->leader = castNode(CteScanState, DatumGetPointer(prmdata->value));
if (scanstate->leader == NULL)
{
/* I am the leader */
prmdata->value = PointerGetDatum(scanstate);
scanstate->leader = scanstate;
scanstate->cte_table = tuplestore_begin_heap(true, false, work_mem);
tuplestore_set_eflags(scanstate->cte_table, scanstate->eflags);
scanstate->readptr = 0;
}
else
{
/* Not the leader */
/* Create my own read pointer, and ensure it is at start */
scanstate->readptr =
tuplestore_alloc_read_pointer(scanstate->leader->cte_table,
scanstate->eflags);
tuplestore_select_read_pointer(scanstate->leader->cte_table,
scanstate->readptr);
tuplestore_rescan(scanstate->leader->cte_table);
}
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &scanstate->ss.ps);
/*
* The scan tuple type (ie, the rowtype we expect to find in the work
* table) is the same as the result rowtype of the CTE query.
*/
ExecInitScanTupleSlot(estate, &scanstate->ss,
ExecGetResultType(scanstate->cteplanstate),
&TTSOpsMinimalTuple);
/*
* Initialize result type and projection.
*/
ExecInitResultTypeTL(&scanstate->ss.ps);
ExecAssignScanProjectionInfo(&scanstate->ss);
/*
* initialize child expressions
*/
scanstate->ss.ps.qual =
ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
return scanstate;
}
/* ----------------------------------------------------------------
* ExecInitSubqueryScan
* ----------------------------------------------------------------
*/
SubqueryScanState *
ExecInitSubqueryScan(SubqueryScan *node, EState *estate, int eflags)
{
SubqueryScanState *subquerystate;
/* check for unsupported flags */
Assert(!(eflags & EXEC_FLAG_MARK));
/* SubqueryScan should not have any "normal" children */
Assert(outerPlan(node) == NULL);
Assert(innerPlan(node) == NULL);
/*
* create state structure
*/
subquerystate = makeNode(SubqueryScanState);
subquerystate->ss.ps.plan = (Plan *) node;
subquerystate->ss.ps.state = estate;
subquerystate->ss.ps.ExecProcNode = ExecSubqueryScan;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &subquerystate->ss.ps);
/*
* initialize subquery
*/
subquerystate->subplan = ExecInitNode(node->subplan, estate, eflags);
/*
* Initialize scan slot and type (needed by ExecAssignScanProjectionInfo)
*/
ExecInitScanTupleSlot(estate, &subquerystate->ss,
ExecGetResultType(subquerystate->subplan),
ExecGetResultSlotOps(subquerystate->subplan, NULL));
/*
* The slot used as the scantuple isn't the slot above (outside of EPQ),
* but the one from the node below.
*/
subquerystate->ss.ps.scanopsset = true;
subquerystate->ss.ps.scanops = ExecGetResultSlotOps(subquerystate->subplan,
&subquerystate->ss.ps.scanopsfixed);
subquerystate->ss.ps.resultopsset = true;
subquerystate->ss.ps.resultops = subquerystate->ss.ps.scanops;
subquerystate->ss.ps.resultopsfixed = subquerystate->ss.ps.scanopsfixed;
/*
* Initialize result type and projection.
*/
ExecInitResultTypeTL(&subquerystate->ss.ps);
ExecAssignScanProjectionInfo(&subquerystate->ss);
/*
* initialize child expressions
*/
subquerystate->ss.ps.qual =
ExecInitQual(node->scan.plan.qual, (PlanState *) subquerystate);
return subquerystate;
}
/* ----------------------------------------------------------------
* ExecInitBitmapHeapScan
*
* Initializes the scan's state information.
* ----------------------------------------------------------------
*/
BitmapHeapScanState *
ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags)
{
BitmapHeapScanState *scanstate;
Relation currentRelation;
int io_concurrency;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* Assert caller didn't ask for an unsafe snapshot --- see comments at
* head of file.
*/
Assert(IsMVCCSnapshot(estate->es_snapshot));
/*
* create state structure
*/
scanstate = makeNode(BitmapHeapScanState);
scanstate->ss.ps.plan = (Plan *) node;
scanstate->ss.ps.state = estate;
scanstate->ss.ps.ExecProcNode = ExecBitmapHeapScan;
scanstate->tbm = NULL;
scanstate->tbmiterator = NULL;
scanstate->tbmres = NULL;
scanstate->exact_pages = 0;
scanstate->lossy_pages = 0;
scanstate->prefetch_iterator = NULL;
scanstate->prefetch_pages = 0;
scanstate->prefetch_target = 0;
/* may be updated below */
scanstate->prefetch_maximum = target_prefetch_pages;
scanstate->pscan_len = 0;
scanstate->initialized = false;
scanstate->shared_tbmiterator = NULL;
scanstate->pstate = NULL;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &scanstate->ss.ps);
/*
* initialize child expressions
*/
scanstate->ss.ps.qual =
ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
scanstate->bitmapqualorig =
ExecInitQual(node->bitmapqualorig, (PlanState *) scanstate);
/*
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
ExecInitScanTupleSlot(estate, &scanstate->ss);
/*
* open the base relation and acquire appropriate lock on it.
*/
currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
/*
* Determine the maximum for prefetch_target. If the tablespace has a
* specific IO concurrency set, use that to compute the corresponding
* maximum value; otherwise, we already initialized to the value computed
* by the GUC machinery.
*/
io_concurrency =
get_tablespace_io_concurrency(currentRelation->rd_rel->reltablespace);
if (io_concurrency != effective_io_concurrency)
{
double maximum;
if (ComputeIoConcurrency(io_concurrency, &maximum))
scanstate->prefetch_maximum = rint(maximum);
}
scanstate->ss.ss_currentRelation = currentRelation;
/*
* Even though we aren't going to do a conventional seqscan, it is useful
* to create a HeapScanDesc --- most of the fields in it are usable.
*/
scanstate->ss.ss_currentScanDesc = heap_beginscan_bm(currentRelation,
estate->es_snapshot,
0,
NULL);
/*
* get the scan type from the relation descriptor.
*/
ExecAssignScanType(&scanstate->ss, RelationGetDescr(currentRelation));
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(&scanstate->ss.ps);
ExecAssignScanProjectionInfo(&scanstate->ss);
/*
* initialize child nodes
*
* We do this last because the child nodes will open indexscans on our
* relation's indexes, and we want to be sure we have acquired a lock on
* the relation first.
*/
outerPlanState(scanstate) = ExecInitNode(outerPlan(node), estate, eflags);
/*
* all done.
*/
return scanstate;
}
/* ----------------------------------------------------------------
* ExecInitGather
* ----------------------------------------------------------------
*/
GatherMergeState *
ExecInitGatherMerge(GatherMerge *node, EState *estate, int eflags)
{
GatherMergeState *gm_state;
Plan *outerNode;
bool hasoid;
TupleDesc tupDesc;
/* Gather merge node doesn't have innerPlan node. */
Assert(innerPlan(node) == NULL);
/*
* create state structure
*/
gm_state = makeNode(GatherMergeState);
gm_state->ps.plan = (Plan *) node;
gm_state->ps.state = estate;
gm_state->ps.ExecProcNode = ExecGatherMerge;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &gm_state->ps);
/*
* initialize child expressions
*/
gm_state->ps.qual =
ExecInitQual(node->plan.qual, &gm_state->ps);
/*
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &gm_state->ps);
/*
* now initialize outer plan
*/
outerNode = outerPlan(node);
outerPlanState(gm_state) = ExecInitNode(outerNode, estate, eflags);
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(&gm_state->ps);
ExecAssignProjectionInfo(&gm_state->ps, NULL);
gm_state->gm_initialized = false;
/*
* initialize sort-key information
*/
if (node->numCols)
{
int i;
gm_state->gm_nkeys = node->numCols;
gm_state->gm_sortkeys =
palloc0(sizeof(SortSupportData) * node->numCols);
for (i = 0; i < node->numCols; i++)
{
SortSupport sortKey = gm_state->gm_sortkeys + i;
sortKey->ssup_cxt = CurrentMemoryContext;
sortKey->ssup_collation = node->collations[i];
sortKey->ssup_nulls_first = node->nullsFirst[i];
sortKey->ssup_attno = node->sortColIdx[i];
/*
* We don't perform abbreviated key conversion here, for the same
* reasons that it isn't used in MergeAppend
*/
sortKey->abbreviate = false;
PrepareSortSupportFromOrderingOp(node->sortOperators[i], sortKey);
}
}
/*
* store the tuple descriptor into gather merge state, so we can use it
* later while initializing the gather merge slots.
*/
if (!ExecContextForcesOids(&gm_state->ps, &hasoid))
hasoid = false;
tupDesc = ExecTypeFromTL(outerNode->targetlist, hasoid);
gm_state->tupDesc = tupDesc;
return gm_state;
}
/* ----------------------------------------------------------------
* ExecInitBitmapHeapScan
*
* Initializes the scan's state information.
* ----------------------------------------------------------------
*/
BitmapHeapScanState *
ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags)
{
BitmapHeapScanState *scanstate;
Relation currentRelation;
int io_concurrency;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* Assert caller didn't ask for an unsafe snapshot --- see comments at
* head of file.
*/
Assert(IsMVCCSnapshot(estate->es_snapshot));
/*
* create state structure
*/
scanstate = makeNode(BitmapHeapScanState);
scanstate->ss.ps.plan = (Plan *) node;
scanstate->ss.ps.state = estate;
scanstate->ss.ps.ExecProcNode = ExecBitmapHeapScan;
scanstate->tbm = NULL;
scanstate->tbmiterator = NULL;
scanstate->tbmres = NULL;
scanstate->skip_fetch = false;
scanstate->vmbuffer = InvalidBuffer;
scanstate->pvmbuffer = InvalidBuffer;
scanstate->exact_pages = 0;
scanstate->lossy_pages = 0;
scanstate->prefetch_iterator = NULL;
scanstate->prefetch_pages = 0;
scanstate->prefetch_target = 0;
/* may be updated below */
scanstate->prefetch_maximum = target_prefetch_pages;
scanstate->pscan_len = 0;
scanstate->initialized = false;
scanstate->shared_tbmiterator = NULL;
scanstate->shared_prefetch_iterator = NULL;
scanstate->pstate = NULL;
/*
* We can potentially skip fetching heap pages if we do not need any
* columns of the table, either for checking non-indexable quals or for
* returning data. This test is a bit simplistic, as it checks the
* stronger condition that there's no qual or return tlist at all. But in
* most cases it's probably not worth working harder than that.
*/
scanstate->can_skip_fetch = (node->scan.plan.qual == NIL &&
node->scan.plan.targetlist == NIL);
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &scanstate->ss.ps);
/*
* open the scan relation
*/
currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
/*
* initialize child nodes
*/
outerPlanState(scanstate) = ExecInitNode(outerPlan(node), estate, eflags);
/*
* get the scan type from the relation descriptor.
*/
ExecInitScanTupleSlot(estate, &scanstate->ss,
RelationGetDescr(currentRelation),
&TTSOpsBufferHeapTuple);
/*
* Initialize result type and projection.
*/
ExecInitResultTypeTL(&scanstate->ss.ps);
ExecAssignScanProjectionInfo(&scanstate->ss);
/*
* initialize child expressions
*/
scanstate->ss.ps.qual =
ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
scanstate->bitmapqualorig =
ExecInitQual(node->bitmapqualorig, (PlanState *) scanstate);
/*
* Determine the maximum for prefetch_target. If the tablespace has a
* specific IO concurrency set, use that to compute the corresponding
* maximum value; otherwise, we already initialized to the value computed
* by the GUC machinery.
*/
io_concurrency =
get_tablespace_io_concurrency(currentRelation->rd_rel->reltablespace);
if (io_concurrency != effective_io_concurrency)
{
double maximum;
if (ComputeIoConcurrency(io_concurrency, &maximum))
scanstate->prefetch_maximum = rint(maximum);
}
scanstate->ss.ss_currentRelation = currentRelation;
/*
* Even though we aren't going to do a conventional seqscan, it is useful
* to create a HeapScanDesc --- most of the fields in it are usable.
*/
scanstate->ss.ss_currentScanDesc = heap_beginscan_bm(currentRelation,
estate->es_snapshot,
0,
NULL);
/*
* all done.
*/
return scanstate;
}