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postgresql/src/backend/executor/nodeIndexscan.c

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/*-------------------------------------------------------------------------
*
* nodeIndexscan.c
* Routines to support indexed scans of relations
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/executor/nodeIndexscan.c
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* ExecIndexScan scans a relation using an index
* IndexNext retrieve next tuple using index
* IndexNextWithReorder same, but recheck ORDER BY expressions
* ExecInitIndexScan creates and initializes state info.
* ExecReScanIndexScan rescans the indexed relation.
* ExecEndIndexScan releases all storage.
* ExecIndexMarkPos marks scan position.
* ExecIndexRestrPos restores scan position.
* ExecIndexScanEstimate estimates DSM space needed for parallel index scan
* ExecIndexScanInitializeDSM initialize DSM for parallel indexscan
* ExecIndexScanReInitializeDSM reinitialize DSM for fresh scan
* ExecIndexScanInitializeWorker attach to DSM info in parallel worker
*/
#include "postgres.h"
#include "access/nbtree.h"
#include "access/relscan.h"
#include "access/tableam.h"
#include "catalog/pg_am.h"
#include "executor/execdebug.h"
#include "executor/nodeIndexscan.h"
#include "lib/pairingheap.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "utils/array.h"
#include "utils/datum.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
/*
* When an ordering operator is used, tuples fetched from the index that
* need to be reordered are queued in a pairing heap, as ReorderTuples.
*/
typedef struct
{
pairingheap_node ph_node;
HeapTuple htup;
Datum *orderbyvals;
bool *orderbynulls;
} ReorderTuple;
static TupleTableSlot *IndexNext(IndexScanState *node);
static TupleTableSlot *IndexNextWithReorder(IndexScanState *node);
static void EvalOrderByExpressions(IndexScanState *node, ExprContext *econtext);
static bool IndexRecheck(IndexScanState *node, TupleTableSlot *slot);
static int cmp_orderbyvals(const Datum *adist, const bool *anulls,
const Datum *bdist, const bool *bnulls,
IndexScanState *node);
static int reorderqueue_cmp(const pairingheap_node *a,
const pairingheap_node *b, void *arg);
static void reorderqueue_push(IndexScanState *node, TupleTableSlot *slot,
Datum *orderbyvals, bool *orderbynulls);
static HeapTuple reorderqueue_pop(IndexScanState *node);
/* ----------------------------------------------------------------
* IndexNext
*
* Retrieve a tuple from the IndexScan node's currentRelation
* using the index specified in the IndexScanState information.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
IndexNext(IndexScanState *node)
{
EState *estate;
ExprContext *econtext;
ScanDirection direction;
IndexScanDesc scandesc;
TupleTableSlot *slot;
/*
* extract necessary information from index scan node
*/
estate = node->ss.ps.state;
direction = estate->es_direction;
/* flip direction if this is an overall backward scan */
if (ScanDirectionIsBackward(((IndexScan *) node->ss.ps.plan)->indexorderdir))
{
if (ScanDirectionIsForward(direction))
direction = BackwardScanDirection;
else if (ScanDirectionIsBackward(direction))
direction = ForwardScanDirection;
}
scandesc = node->iss_ScanDesc;
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
if (scandesc == NULL)
{
/*
* We reach here if the index scan is not parallel, or if we're
* serially executing an index scan that was planned to be parallel.
*/
scandesc = index_beginscan(node->ss.ss_currentRelation,
node->iss_RelationDesc,
estate->es_snapshot,
node->iss_NumScanKeys,
node->iss_NumOrderByKeys);
node->iss_ScanDesc = scandesc;
/*
* If no run-time keys to calculate or they are ready, go ahead and
* pass the scankeys to the index AM.
*/
if (node->iss_NumRuntimeKeys == 0 || node->iss_RuntimeKeysReady)
index_rescan(scandesc,
node->iss_ScanKeys, node->iss_NumScanKeys,
node->iss_OrderByKeys, node->iss_NumOrderByKeys);
}
/*
* ok, now that we have what we need, fetch the next tuple.
*/
while (index_getnext_slot(scandesc, direction, slot))
{
CHECK_FOR_INTERRUPTS();
/*
* If the index was lossy, we have to recheck the index quals using
* the fetched tuple.
*/
if (scandesc->xs_recheck)
{
econtext->ecxt_scantuple = slot;
if (!ExecQualAndReset(node->indexqualorig, econtext))
{
/* Fails recheck, so drop it and loop back for another */
InstrCountFiltered2(node, 1);
continue;
}
}
return slot;
}
/*
* if we get here it means the index scan failed so we are at the end of
* the scan..
*/
node->iss_ReachedEnd = true;
return ExecClearTuple(slot);
}
/* ----------------------------------------------------------------
* IndexNextWithReorder
*
* Like IndexNext, but this version can also re-check ORDER BY
* expressions, and reorder the tuples as necessary.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
IndexNextWithReorder(IndexScanState *node)
{
EState *estate;
ExprContext *econtext;
IndexScanDesc scandesc;
TupleTableSlot *slot;
ReorderTuple *topmost = NULL;
bool was_exact;
Datum *lastfetched_vals;
bool *lastfetched_nulls;
int cmp;
estate = node->ss.ps.state;
/*
* Only forward scan is supported with reordering. Note: we can get away
* with just Asserting here because the system will not try to run the
* plan backwards if ExecSupportsBackwardScan() says it won't work.
* Currently, that is guaranteed because no index AMs support both
* amcanorderbyop and amcanbackward; if any ever do,
* ExecSupportsBackwardScan() will need to consider indexorderbys
* explicitly.
*/
Assert(!ScanDirectionIsBackward(((IndexScan *) node->ss.ps.plan)->indexorderdir));
Assert(ScanDirectionIsForward(estate->es_direction));
scandesc = node->iss_ScanDesc;
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
if (scandesc == NULL)
{
/*
* We reach here if the index scan is not parallel, or if we're
* serially executing an index scan that was planned to be parallel.
*/
scandesc = index_beginscan(node->ss.ss_currentRelation,
node->iss_RelationDesc,
estate->es_snapshot,
node->iss_NumScanKeys,
node->iss_NumOrderByKeys);
node->iss_ScanDesc = scandesc;
/*
* If no run-time keys to calculate or they are ready, go ahead and
* pass the scankeys to the index AM.
*/
if (node->iss_NumRuntimeKeys == 0 || node->iss_RuntimeKeysReady)
index_rescan(scandesc,
node->iss_ScanKeys, node->iss_NumScanKeys,
node->iss_OrderByKeys, node->iss_NumOrderByKeys);
}
for (;;)
{
CHECK_FOR_INTERRUPTS();
/*
* Check the reorder queue first. If the topmost tuple in the queue
* has an ORDER BY value smaller than (or equal to) the value last
* returned by the index, we can return it now.
*/
if (!pairingheap_is_empty(node->iss_ReorderQueue))
{
topmost = (ReorderTuple *) pairingheap_first(node->iss_ReorderQueue);
if (node->iss_ReachedEnd ||
cmp_orderbyvals(topmost->orderbyvals,
topmost->orderbynulls,
scandesc->xs_orderbyvals,
scandesc->xs_orderbynulls,
node) <= 0)
{
HeapTuple tuple;
tuple = reorderqueue_pop(node);
/* Pass 'true', as the tuple in the queue is a palloc'd copy */
ExecForceStoreHeapTuple(tuple, slot, true);
return slot;
}
}
else if (node->iss_ReachedEnd)
{
/* Queue is empty, and no more tuples from index. We're done. */
return ExecClearTuple(slot);
}
/*
* Fetch next tuple from the index.
*/
next_indextuple:
if (!index_getnext_slot(scandesc, ForwardScanDirection, slot))
{
/*
* No more tuples from the index. But we still need to drain any
* remaining tuples from the queue before we're done.
*/
node->iss_ReachedEnd = true;
continue;
}
/*
* If the index was lossy, we have to recheck the index quals and
* ORDER BY expressions using the fetched tuple.
*/
if (scandesc->xs_recheck)
{
econtext->ecxt_scantuple = slot;
if (!ExecQualAndReset(node->indexqualorig, econtext))
{
/* Fails recheck, so drop it and loop back for another */
InstrCountFiltered2(node, 1);
/* allow this loop to be cancellable */
CHECK_FOR_INTERRUPTS();
goto next_indextuple;
}
}
if (scandesc->xs_recheckorderby)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
EvalOrderByExpressions(node, econtext);
/*
* Was the ORDER BY value returned by the index accurate? The
* recheck flag means that the index can return inaccurate values,
* but then again, the value returned for any particular tuple
* could also be exactly correct. Compare the value returned by
* the index with the recalculated value. (If the value returned
* by the index happened to be exact right, we can often avoid
* pushing the tuple to the queue, just to pop it back out again.)
*/
cmp = cmp_orderbyvals(node->iss_OrderByValues,
node->iss_OrderByNulls,
scandesc->xs_orderbyvals,
scandesc->xs_orderbynulls,
node);
if (cmp < 0)
elog(ERROR, "index returned tuples in wrong order");
else if (cmp == 0)
was_exact = true;
else
was_exact = false;
lastfetched_vals = node->iss_OrderByValues;
lastfetched_nulls = node->iss_OrderByNulls;
}
else
{
was_exact = true;
lastfetched_vals = scandesc->xs_orderbyvals;
lastfetched_nulls = scandesc->xs_orderbynulls;
}
/*
* Can we return this tuple immediately, or does it need to be pushed
* to the reorder queue? If the ORDER BY expression values returned
* by the index were inaccurate, we can't return it yet, because the
* next tuple from the index might need to come before this one. Also,
* we can't return it yet if there are any smaller tuples in the queue
* already.
*/
if (!was_exact || (topmost && cmp_orderbyvals(lastfetched_vals,
lastfetched_nulls,
topmost->orderbyvals,
topmost->orderbynulls,
node) > 0))
{
/* Put this tuple to the queue */
reorderqueue_push(node, slot, lastfetched_vals, lastfetched_nulls);
continue;
}
else
{
/* Can return this tuple immediately. */
return slot;
}
}
/*
* if we get here it means the index scan failed so we are at the end of
* the scan..
*/
return ExecClearTuple(slot);
}
/*
* Calculate the expressions in the ORDER BY clause, based on the heap tuple.
*/
static void
EvalOrderByExpressions(IndexScanState *node, ExprContext *econtext)
{
int i;
ListCell *l;
MemoryContext oldContext;
oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
i = 0;
foreach(l, node->indexorderbyorig)
{
ExprState *orderby = (ExprState *) lfirst(l);
node->iss_OrderByValues[i] = ExecEvalExpr(orderby,
econtext,
&node->iss_OrderByNulls[i]);
i++;
}
MemoryContextSwitchTo(oldContext);
}
/*
* IndexRecheck -- access method routine to recheck a tuple in EvalPlanQual
*/
static bool
IndexRecheck(IndexScanState *node, TupleTableSlot *slot)
{
ExprContext *econtext;
/*
* extract necessary information from index scan node
*/
econtext = node->ss.ps.ps_ExprContext;
/* Does the tuple meet the indexqual condition? */
econtext->ecxt_scantuple = slot;
return ExecQualAndReset(node->indexqualorig, econtext);
}
/*
* Compare ORDER BY expression values.
*/
static int
cmp_orderbyvals(const Datum *adist, const bool *anulls,
const Datum *bdist, const bool *bnulls,
IndexScanState *node)
{
int i;
int result;
for (i = 0; i < node->iss_NumOrderByKeys; i++)
{
SortSupport ssup = &node->iss_SortSupport[i];
/*
* Handle nulls. We only need to support NULLS LAST ordering, because
* match_pathkeys_to_index() doesn't consider indexorderby
* implementation otherwise.
*/
if (anulls[i] && !bnulls[i])
return 1;
else if (!anulls[i] && bnulls[i])
return -1;
else if (anulls[i] && bnulls[i])
return 0;
result = ssup->comparator(adist[i], bdist[i], ssup);
if (result != 0)
return result;
}
return 0;
}
/*
* Pairing heap provides getting topmost (greatest) element while KNN provides
* ascending sort. That's why we invert the sort order.
*/
static int
reorderqueue_cmp(const pairingheap_node *a, const pairingheap_node *b,
void *arg)
{
ReorderTuple *rta = (ReorderTuple *) a;
ReorderTuple *rtb = (ReorderTuple *) b;
IndexScanState *node = (IndexScanState *) arg;
/* exchange argument order to invert the sort order */
return cmp_orderbyvals(rtb->orderbyvals, rtb->orderbynulls,
rta->orderbyvals, rta->orderbynulls,
node);
}
/*
* Helper function to push a tuple to the reorder queue.
*/
static void
reorderqueue_push(IndexScanState *node, TupleTableSlot *slot,
Datum *orderbyvals, bool *orderbynulls)
{
IndexScanDesc scandesc = node->iss_ScanDesc;
EState *estate = node->ss.ps.state;
MemoryContext oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
ReorderTuple *rt;
int i;
rt = (ReorderTuple *) palloc(sizeof(ReorderTuple));
rt->htup = ExecCopySlotHeapTuple(slot);
rt->orderbyvals =
(Datum *) palloc(sizeof(Datum) * scandesc->numberOfOrderBys);
rt->orderbynulls =
(bool *) palloc(sizeof(bool) * scandesc->numberOfOrderBys);
for (i = 0; i < node->iss_NumOrderByKeys; i++)
{
if (!orderbynulls[i])
rt->orderbyvals[i] = datumCopy(orderbyvals[i],
node->iss_OrderByTypByVals[i],
node->iss_OrderByTypLens[i]);
else
rt->orderbyvals[i] = (Datum) 0;
rt->orderbynulls[i] = orderbynulls[i];
}
pairingheap_add(node->iss_ReorderQueue, &rt->ph_node);
MemoryContextSwitchTo(oldContext);
}
/*
* Helper function to pop the next tuple from the reorder queue.
*/
static HeapTuple
reorderqueue_pop(IndexScanState *node)
{
HeapTuple result;
ReorderTuple *topmost;
int i;
topmost = (ReorderTuple *) pairingheap_remove_first(node->iss_ReorderQueue);
result = topmost->htup;
for (i = 0; i < node->iss_NumOrderByKeys; i++)
{
if (!node->iss_OrderByTypByVals[i] && !topmost->orderbynulls[i])
pfree(DatumGetPointer(topmost->orderbyvals[i]));
}
pfree(topmost->orderbyvals);
pfree(topmost->orderbynulls);
pfree(topmost);
return result;
}
/* ----------------------------------------------------------------
* ExecIndexScan(node)
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecIndexScan(PlanState *pstate)
{
IndexScanState *node = castNode(IndexScanState, pstate);
/*
* If we have runtime keys and they've not already been set up, do it now.
*/
if (node->iss_NumRuntimeKeys != 0 && !node->iss_RuntimeKeysReady)
ExecReScan((PlanState *) node);
if (node->iss_NumOrderByKeys > 0)
return ExecScan(&node->ss,
(ExecScanAccessMtd) IndexNextWithReorder,
(ExecScanRecheckMtd) IndexRecheck);
else
return ExecScan(&node->ss,
(ExecScanAccessMtd) IndexNext,
(ExecScanRecheckMtd) IndexRecheck);
}
/* ----------------------------------------------------------------
* ExecReScanIndexScan(node)
*
* Recalculates the values of any scan keys whose value depends on
* information known at runtime, then rescans the indexed relation.
*
* Updating the scan key was formerly done separately in
* ExecUpdateIndexScanKeys. Integrating it into ReScan makes
* rescans of indices and relations/general streams more uniform.
* ----------------------------------------------------------------
*/
void
ExecReScanIndexScan(IndexScanState *node)
{
/*
* If we are doing runtime key calculations (ie, any of the index key
* values weren't simple Consts), compute the new key values. But first,
* reset the context so we don't leak memory as each outer tuple is
* scanned. Note this assumes that we will recalculate *all* runtime keys
* on each call.
*/
if (node->iss_NumRuntimeKeys != 0)
{
ExprContext *econtext = node->iss_RuntimeContext;
ResetExprContext(econtext);
ExecIndexEvalRuntimeKeys(econtext,
node->iss_RuntimeKeys,
node->iss_NumRuntimeKeys);
}
node->iss_RuntimeKeysReady = true;
/* flush the reorder queue */
if (node->iss_ReorderQueue)
{
while (!pairingheap_is_empty(node->iss_ReorderQueue))
reorderqueue_pop(node);
}
/* reset index scan */
if (node->iss_ScanDesc)
index_rescan(node->iss_ScanDesc,
node->iss_ScanKeys, node->iss_NumScanKeys,
node->iss_OrderByKeys, node->iss_NumOrderByKeys);
node->iss_ReachedEnd = false;
ExecScanReScan(&node->ss);
}
/*
* ExecIndexEvalRuntimeKeys
* Evaluate any runtime key values, and update the scankeys.
*/
void
ExecIndexEvalRuntimeKeys(ExprContext *econtext,
IndexRuntimeKeyInfo *runtimeKeys, int numRuntimeKeys)
{
int j;
MemoryContext oldContext;
/* We want to keep the key values in per-tuple memory */
oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
for (j = 0; j < numRuntimeKeys; j++)
{
ScanKey scan_key = runtimeKeys[j].scan_key;
ExprState *key_expr = runtimeKeys[j].key_expr;
Datum scanvalue;
bool isNull;
/*
* For each run-time key, extract the run-time expression and evaluate
* it with respect to the current context. We then stick the result
* into the proper scan key.
*
* Note: the result of the eval could be a pass-by-ref value that's
* stored in some outer scan's tuple, not in
* econtext->ecxt_per_tuple_memory. We assume that the outer tuple
* will stay put throughout our scan. If this is wrong, we could copy
* the result into our context explicitly, but I think that's not
* necessary.
*
* It's also entirely possible that the result of the eval is a
* toasted value. In this case we should forcibly detoast it, to
* avoid repeat detoastings each time the value is examined by an
* index support function.
*/
scanvalue = ExecEvalExpr(key_expr,
econtext,
&isNull);
if (isNull)
{
scan_key->sk_argument = scanvalue;
scan_key->sk_flags |= SK_ISNULL;
}
else
{
if (runtimeKeys[j].key_toastable)
scanvalue = PointerGetDatum(PG_DETOAST_DATUM(scanvalue));
scan_key->sk_argument = scanvalue;
scan_key->sk_flags &= ~SK_ISNULL;
}
}
MemoryContextSwitchTo(oldContext);
}
/*
* ExecIndexEvalArrayKeys
* Evaluate any array key values, and set up to iterate through arrays.
*
* Returns true if there are array elements to consider; false means there
* is at least one null or empty array, so no match is possible. On true
* result, the scankeys are initialized with the first elements of the arrays.
*/
bool
ExecIndexEvalArrayKeys(ExprContext *econtext,
IndexArrayKeyInfo *arrayKeys, int numArrayKeys)
{
bool result = true;
int j;
MemoryContext oldContext;
/* We want to keep the arrays in per-tuple memory */
oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
for (j = 0; j < numArrayKeys; j++)
{
ScanKey scan_key = arrayKeys[j].scan_key;
ExprState *array_expr = arrayKeys[j].array_expr;
Datum arraydatum;
bool isNull;
ArrayType *arrayval;
int16 elmlen;
bool elmbyval;
char elmalign;
int num_elems;
Datum *elem_values;
bool *elem_nulls;
/*
* Compute and deconstruct the array expression. (Notes in
* ExecIndexEvalRuntimeKeys() apply here too.)
*/
arraydatum = ExecEvalExpr(array_expr,
econtext,
&isNull);
if (isNull)
{
result = false;
break; /* no point in evaluating more */
}
arrayval = DatumGetArrayTypeP(arraydatum);
/* We could cache this data, but not clear it's worth it */
get_typlenbyvalalign(ARR_ELEMTYPE(arrayval),
&elmlen, &elmbyval, &elmalign);
deconstruct_array(arrayval,
ARR_ELEMTYPE(arrayval),
elmlen, elmbyval, elmalign,
&elem_values, &elem_nulls, &num_elems);
if (num_elems <= 0)
{
result = false;
break; /* no point in evaluating more */
}
/*
* Note: we expect the previous array data, if any, to be
* automatically freed by resetting the per-tuple context; hence no
* pfree's here.
*/
arrayKeys[j].elem_values = elem_values;
arrayKeys[j].elem_nulls = elem_nulls;
arrayKeys[j].num_elems = num_elems;
scan_key->sk_argument = elem_values[0];
if (elem_nulls[0])
scan_key->sk_flags |= SK_ISNULL;
else
scan_key->sk_flags &= ~SK_ISNULL;
arrayKeys[j].next_elem = 1;
}
MemoryContextSwitchTo(oldContext);
return result;
}
/*
* ExecIndexAdvanceArrayKeys
* Advance to the next set of array key values, if any.
*
* Returns true if there is another set of values to consider, false if not.
* On true result, the scankeys are initialized with the next set of values.
*/
bool
ExecIndexAdvanceArrayKeys(IndexArrayKeyInfo *arrayKeys, int numArrayKeys)
{
bool found = false;
int j;
/*
* Note we advance the rightmost array key most quickly, since it will
* correspond to the lowest-order index column among the available
* qualifications. This is hypothesized to result in better locality of
* access in the index.
*/
for (j = numArrayKeys - 1; j >= 0; j--)
{
ScanKey scan_key = arrayKeys[j].scan_key;
int next_elem = arrayKeys[j].next_elem;
int num_elems = arrayKeys[j].num_elems;
Datum *elem_values = arrayKeys[j].elem_values;
bool *elem_nulls = arrayKeys[j].elem_nulls;
if (next_elem >= num_elems)
{
next_elem = 0;
found = false; /* need to advance next array key */
}
else
found = true;
scan_key->sk_argument = elem_values[next_elem];
if (elem_nulls[next_elem])
scan_key->sk_flags |= SK_ISNULL;
else
scan_key->sk_flags &= ~SK_ISNULL;
arrayKeys[j].next_elem = next_elem + 1;
if (found)
break;
}
return found;
}
/* ----------------------------------------------------------------
* ExecEndIndexScan
* ----------------------------------------------------------------
*/
void
ExecEndIndexScan(IndexScanState *node)
{
Relation indexRelationDesc;
IndexScanDesc indexScanDesc;
/*
* extract information from the node
*/
indexRelationDesc = node->iss_RelationDesc;
indexScanDesc = node->iss_ScanDesc;
/*
* Free the exprcontext(s) ... now dead code, see ExecFreeExprContext
*/
#ifdef NOT_USED
ExecFreeExprContext(&node->ss.ps);
if (node->iss_RuntimeContext)
FreeExprContext(node->iss_RuntimeContext, true);
#endif
/*
* clear out tuple table slots
*/
if (node->ss.ps.ps_ResultTupleSlot)
ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
ExecClearTuple(node->ss.ss_ScanTupleSlot);
/*
* close the index relation (no-op if we didn't open it)
*/
if (indexScanDesc)
index_endscan(indexScanDesc);
if (indexRelationDesc)
index_close(indexRelationDesc, NoLock);
}
/* ----------------------------------------------------------------
* ExecIndexMarkPos
*
* Note: we assume that no caller attempts to set a mark before having read
* at least one tuple. Otherwise, iss_ScanDesc might still be NULL.
* ----------------------------------------------------------------
*/
void
ExecIndexMarkPos(IndexScanState *node)
{
EState *estate = node->ss.ps.state;
if (estate->es_epqTupleSlot != NULL)
{
/*
* We are inside an EvalPlanQual recheck. If a test tuple exists for
* this relation, then we shouldn't access the index at all. We would
* instead need to save, and later restore, the state of the
* es_epqScanDone flag, so that re-fetching the test tuple is
* possible. However, given the assumption that no caller sets a mark
* at the start of the scan, we can only get here with es_epqScanDone
* already set, and so no state need be saved.
*/
Index scanrelid = ((Scan *) node->ss.ps.plan)->scanrelid;
Assert(scanrelid > 0);
if (estate->es_epqTupleSlot[scanrelid - 1] != NULL)
{
/* Verify the claim above */
if (!estate->es_epqScanDone[scanrelid - 1])
elog(ERROR, "unexpected ExecIndexMarkPos call in EPQ recheck");
return;
}
}
index_markpos(node->iss_ScanDesc);
}
/* ----------------------------------------------------------------
* ExecIndexRestrPos
* ----------------------------------------------------------------
*/
void
ExecIndexRestrPos(IndexScanState *node)
{
EState *estate = node->ss.ps.state;
if (estate->es_epqTupleSlot != NULL)
{
/* See comments in ExecIndexMarkPos */
Index scanrelid = ((Scan *) node->ss.ps.plan)->scanrelid;
Assert(scanrelid > 0);
if (estate->es_epqTupleSlot[scanrelid - 1] != NULL)
{
/* Verify the claim above */
if (!estate->es_epqScanDone[scanrelid - 1])
elog(ERROR, "unexpected ExecIndexRestrPos call in EPQ recheck");
return;
}
}
index_restrpos(node->iss_ScanDesc);
}
/* ----------------------------------------------------------------
* ExecInitIndexScan
*
* 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.
* ----------------------------------------------------------------
*/
IndexScanState *
ExecInitIndexScan(IndexScan *node, EState *estate, int eflags)
{
IndexScanState *indexstate;
Relation currentRelation;
LOCKMODE lockmode;
/*
* create state structure
*/
indexstate = makeNode(IndexScanState);
indexstate->ss.ps.plan = (Plan *) node;
indexstate->ss.ps.state = estate;
indexstate->ss.ps.ExecProcNode = ExecIndexScan;
/*
* 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 */
/*
* get the scan type from the relation descriptor.
*/
ExecInitScanTupleSlot(estate, &indexstate->ss,
RelationGetDescr(currentRelation),
table_slot_callbacks(currentRelation));
/*
* Initialize result type and projection.
*/
ExecInitResultTypeTL(&indexstate->ss.ps);
ExecAssignScanProjectionInfo(&indexstate->ss);
/*
* initialize child expressions
*
* Note: we don't initialize all of the indexqual expression, only the
* sub-parts corresponding to runtime keys (see below). Likewise for
* indexorderby, if any. But the indexqualorig expression is always
* initialized even though it will only be used in some uncommon cases ---
* would be nice to improve that. (Problem is that any SubPlans present
* in the expression must be found now...)
*/
indexstate->ss.ps.qual =
ExecInitQual(node->scan.plan.qual, (PlanState *) indexstate);
indexstate->indexqualorig =
ExecInitQual(node->indexqualorig, (PlanState *) indexstate);
indexstate->indexorderbyorig =
ExecInitExprList(node->indexorderbyorig, (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. */
lockmode = exec_rt_fetch(node->scan.scanrelid, estate)->rellockmode;
indexstate->iss_RelationDesc = index_open(node->indexid, lockmode);
/*
* Initialize index-specific scan state
*/
indexstate->iss_RuntimeKeysReady = false;
indexstate->iss_RuntimeKeys = NULL;
indexstate->iss_NumRuntimeKeys = 0;
/*
* build the index scan keys from the index qualification
*/
ExecIndexBuildScanKeys((PlanState *) indexstate,
indexstate->iss_RelationDesc,
node->indexqual,
false,
&indexstate->iss_ScanKeys,
&indexstate->iss_NumScanKeys,
&indexstate->iss_RuntimeKeys,
&indexstate->iss_NumRuntimeKeys,
NULL, /* no ArrayKeys */
NULL);
/*
* any ORDER BY exprs have to be turned into scankeys in the same way
*/
ExecIndexBuildScanKeys((PlanState *) indexstate,
indexstate->iss_RelationDesc,
node->indexorderby,
true,
&indexstate->iss_OrderByKeys,
&indexstate->iss_NumOrderByKeys,
&indexstate->iss_RuntimeKeys,
&indexstate->iss_NumRuntimeKeys,
NULL, /* no ArrayKeys */
NULL);
/* Initialize sort support, if we need to re-check ORDER BY exprs */
if (indexstate->iss_NumOrderByKeys > 0)
{
int numOrderByKeys = indexstate->iss_NumOrderByKeys;
int i;
ListCell *lco;
ListCell *lcx;
/*
* Prepare sort support, and look up the data type for each ORDER BY
* expression.
*/
Assert(numOrderByKeys == list_length(node->indexorderbyops));
Assert(numOrderByKeys == list_length(node->indexorderbyorig));
indexstate->iss_SortSupport = (SortSupportData *)
palloc0(numOrderByKeys * sizeof(SortSupportData));
indexstate->iss_OrderByTypByVals = (bool *)
palloc(numOrderByKeys * sizeof(bool));
indexstate->iss_OrderByTypLens = (int16 *)
palloc(numOrderByKeys * sizeof(int16));
i = 0;
forboth(lco, node->indexorderbyops, lcx, node->indexorderbyorig)
{
Oid orderbyop = lfirst_oid(lco);
Node *orderbyexpr = (Node *) lfirst(lcx);
Oid orderbyType = exprType(orderbyexpr);
Oid orderbyColl = exprCollation(orderbyexpr);
SortSupport orderbysort = &indexstate->iss_SortSupport[i];
/* Initialize sort support */
orderbysort->ssup_cxt = CurrentMemoryContext;
orderbysort->ssup_collation = orderbyColl;
/* See cmp_orderbyvals() comments on NULLS LAST */
orderbysort->ssup_nulls_first = false;
/* ssup_attno is unused here and elsewhere */
orderbysort->ssup_attno = 0;
/* No abbreviation */
orderbysort->abbreviate = false;
PrepareSortSupportFromOrderingOp(orderbyop, orderbysort);
get_typlenbyval(orderbyType,
&indexstate->iss_OrderByTypLens[i],
&indexstate->iss_OrderByTypByVals[i]);
i++;
}
/* allocate arrays to hold the re-calculated distances */
indexstate->iss_OrderByValues = (Datum *)
palloc(numOrderByKeys * sizeof(Datum));
indexstate->iss_OrderByNulls = (bool *)
palloc(numOrderByKeys * sizeof(bool));
/* and initialize the reorder queue */
indexstate->iss_ReorderQueue = pairingheap_allocate(reorderqueue_cmp,
indexstate);
}
/*
* 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->iss_NumRuntimeKeys != 0)
{
ExprContext *stdecontext = indexstate->ss.ps.ps_ExprContext;
ExecAssignExprContext(estate, &indexstate->ss.ps);
indexstate->iss_RuntimeContext = indexstate->ss.ps.ps_ExprContext;
indexstate->ss.ps.ps_ExprContext = stdecontext;
}
else
{
indexstate->iss_RuntimeContext = NULL;
}
/*
* all done.
*/
return indexstate;
}
/*
* ExecIndexBuildScanKeys
* Build the index scan keys from the index qualification expressions
*
* The index quals are passed to the index AM in the form of a ScanKey array.
* This routine sets up the ScanKeys, fills in all constant fields of the
* ScanKeys, and prepares information about the keys that have non-constant
* comparison values. We divide index qual expressions into five types:
*
* 1. Simple operator with constant comparison value ("indexkey op constant").
* For these, we just fill in a ScanKey containing the constant value.
*
* 2. Simple operator with non-constant value ("indexkey op expression").
* For these, we create a ScanKey with everything filled in except the
* expression value, and set up an IndexRuntimeKeyInfo struct to drive
* evaluation of the expression at the right times.
*
* 3. RowCompareExpr ("(indexkey, indexkey, ...) op (expr, expr, ...)").
* For these, we create a header ScanKey plus a subsidiary ScanKey array,
* as specified in access/skey.h. The elements of the row comparison
* can have either constant or non-constant comparison values.
*
* 4. ScalarArrayOpExpr ("indexkey op ANY (array-expression)"). If the index
* supports amsearcharray, we handle these the same as simple operators,
* setting the SK_SEARCHARRAY flag to tell the AM to handle them. Otherwise,
* we create a ScanKey with everything filled in except the comparison value,
* and set up an IndexArrayKeyInfo struct to drive processing of the qual.
* (Note that if we use an IndexArrayKeyInfo struct, the array expression is
* always treated as requiring runtime evaluation, even if it's a constant.)
*
* 5. NullTest ("indexkey IS NULL/IS NOT NULL"). We just fill in the
* ScanKey properly.
*
* This code is also used to prepare ORDER BY expressions for amcanorderbyop
* indexes. The behavior is exactly the same, except that we have to look up
* the operator differently. Note that only cases 1 and 2 are currently
* possible for ORDER BY.
*
* Input params are:
*
* planstate: executor state node we are working for
* index: the index we are building scan keys for
* quals: indexquals (or indexorderbys) expressions
* isorderby: true if processing ORDER BY exprs, false if processing quals
* *runtimeKeys: ptr to pre-existing IndexRuntimeKeyInfos, or NULL if none
* *numRuntimeKeys: number of pre-existing runtime keys
*
* Output params are:
*
* *scanKeys: receives ptr to array of ScanKeys
* *numScanKeys: receives number of scankeys
* *runtimeKeys: receives ptr to array of IndexRuntimeKeyInfos, or NULL if none
* *numRuntimeKeys: receives number of runtime keys
* *arrayKeys: receives ptr to array of IndexArrayKeyInfos, or NULL if none
* *numArrayKeys: receives number of array keys
*
* Caller may pass NULL for arrayKeys and numArrayKeys to indicate that
* IndexArrayKeyInfos are not supported.
*/
void
ExecIndexBuildScanKeys(PlanState *planstate, Relation index,
List *quals, bool isorderby,
ScanKey *scanKeys, int *numScanKeys,
IndexRuntimeKeyInfo **runtimeKeys, int *numRuntimeKeys,
IndexArrayKeyInfo **arrayKeys, int *numArrayKeys)
{
ListCell *qual_cell;
ScanKey scan_keys;
IndexRuntimeKeyInfo *runtime_keys;
IndexArrayKeyInfo *array_keys;
int n_scan_keys;
int n_runtime_keys;
int max_runtime_keys;
int n_array_keys;
int j;
/* Allocate array for ScanKey structs: one per qual */
n_scan_keys = list_length(quals);
scan_keys = (ScanKey) palloc(n_scan_keys * sizeof(ScanKeyData));
/*
* runtime_keys array is dynamically resized as needed. We handle it this
* way so that the same runtime keys array can be shared between
* indexquals and indexorderbys, which will be processed in separate calls
* of this function. Caller must be sure to pass in NULL/0 for first
* call.
*/
runtime_keys = *runtimeKeys;
n_runtime_keys = max_runtime_keys = *numRuntimeKeys;
/* Allocate array_keys as large as it could possibly need to be */
array_keys = (IndexArrayKeyInfo *)
palloc0(n_scan_keys * sizeof(IndexArrayKeyInfo));
n_array_keys = 0;
/*
* for each opclause in the given qual, convert the opclause into a single
* scan key
*/
j = 0;
foreach(qual_cell, quals)
{
Expr *clause = (Expr *) lfirst(qual_cell);
ScanKey this_scan_key = &scan_keys[j++];
Oid opno; /* operator's OID */
RegProcedure opfuncid; /* operator proc id used in scan */
Oid opfamily; /* opfamily of index column */
int op_strategy; /* operator's strategy number */
Oid op_lefttype; /* operator's declared input types */
Oid op_righttype;
Expr *leftop; /* expr on lhs of operator */
Expr *rightop; /* expr on rhs ... */
AttrNumber varattno; /* att number used in scan */
int indnkeyatts;
indnkeyatts = IndexRelationGetNumberOfKeyAttributes(index);
if (IsA(clause, OpExpr))
{
/* indexkey op const or indexkey op expression */
int flags = 0;
Datum scanvalue;
opno = ((OpExpr *) clause)->opno;
opfuncid = ((OpExpr *) clause)->opfuncid;
/*
* leftop should be the index key Var, possibly relabeled
*/
leftop = (Expr *) get_leftop(clause);
if (leftop && IsA(leftop, RelabelType))
leftop = ((RelabelType *) leftop)->arg;
Assert(leftop != NULL);
if (!(IsA(leftop, Var) &&
((Var *) leftop)->varno == INDEX_VAR))
elog(ERROR, "indexqual doesn't have key on left side");
varattno = ((Var *) leftop)->varattno;
if (varattno < 1 || varattno > indnkeyatts)
elog(ERROR, "bogus index qualification");
/*
* We have to look up the operator's strategy number. This
* provides a cross-check that the operator does match the index.
*/
opfamily = index->rd_opfamily[varattno - 1];
get_op_opfamily_properties(opno, opfamily, isorderby,
&op_strategy,
&op_lefttype,
&op_righttype);
if (isorderby)
flags |= SK_ORDER_BY;
/*
* rightop is the constant or variable comparison value
*/
rightop = (Expr *) get_rightop(clause);
if (rightop && IsA(rightop, RelabelType))
rightop = ((RelabelType *) rightop)->arg;
Assert(rightop != NULL);
if (IsA(rightop, Const))
{
/* OK, simple constant comparison value */
scanvalue = ((Const *) rightop)->constvalue;
if (((Const *) rightop)->constisnull)
flags |= SK_ISNULL;
}
else
{
/* Need to treat this one as a runtime key */
if (n_runtime_keys >= max_runtime_keys)
{
if (max_runtime_keys == 0)
{
max_runtime_keys = 8;
runtime_keys = (IndexRuntimeKeyInfo *)
palloc(max_runtime_keys * sizeof(IndexRuntimeKeyInfo));
}
else
{
max_runtime_keys *= 2;
runtime_keys = (IndexRuntimeKeyInfo *)
repalloc(runtime_keys, max_runtime_keys * sizeof(IndexRuntimeKeyInfo));
}
}
runtime_keys[n_runtime_keys].scan_key = this_scan_key;
runtime_keys[n_runtime_keys].key_expr =
ExecInitExpr(rightop, planstate);
runtime_keys[n_runtime_keys].key_toastable =
TypeIsToastable(op_righttype);
n_runtime_keys++;
scanvalue = (Datum) 0;
}
/*
* initialize the scan key's fields appropriately
*/
ScanKeyEntryInitialize(this_scan_key,
flags,
varattno, /* attribute number to scan */
op_strategy, /* op's strategy */
op_righttype, /* strategy subtype */
((OpExpr *) clause)->inputcollid, /* collation */
opfuncid, /* reg proc to use */
scanvalue); /* constant */
}
else if (IsA(clause, RowCompareExpr))
{
/* (indexkey, indexkey, ...) op (expression, expression, ...) */
RowCompareExpr *rc = (RowCompareExpr *) clause;
ScanKey first_sub_key;
int n_sub_key;
ListCell *largs_cell;
ListCell *rargs_cell;
ListCell *opnos_cell;
ListCell *collids_cell;
Assert(!isorderby);
first_sub_key = (ScanKey)
palloc(list_length(rc->opnos) * sizeof(ScanKeyData));
n_sub_key = 0;
/* Scan RowCompare columns and generate subsidiary ScanKey items */
forfour(largs_cell, rc->largs, rargs_cell, rc->rargs,
opnos_cell, rc->opnos, collids_cell, rc->inputcollids)
{
ScanKey this_sub_key = &first_sub_key[n_sub_key];
int flags = SK_ROW_MEMBER;
Datum scanvalue;
Oid inputcollation;
leftop = (Expr *) lfirst(largs_cell);
rightop = (Expr *) lfirst(rargs_cell);
opno = lfirst_oid(opnos_cell);
inputcollation = lfirst_oid(collids_cell);
/*
* leftop should be the index key Var, possibly relabeled
*/
if (leftop && IsA(leftop, RelabelType))
leftop = ((RelabelType *) leftop)->arg;
Assert(leftop != NULL);
if (!(IsA(leftop, Var) &&
((Var *) leftop)->varno == INDEX_VAR))
elog(ERROR, "indexqual doesn't have key on left side");
varattno = ((Var *) leftop)->varattno;
/*
* We have to look up the operator's associated btree support
* function
*/
if (index->rd_rel->relam != BTREE_AM_OID ||
varattno < 1 || varattno > indnkeyatts)
elog(ERROR, "bogus RowCompare index qualification");
opfamily = index->rd_opfamily[varattno - 1];
get_op_opfamily_properties(opno, opfamily, isorderby,
&op_strategy,
&op_lefttype,
&op_righttype);
if (op_strategy != rc->rctype)
elog(ERROR, "RowCompare index qualification contains wrong operator");
opfuncid = get_opfamily_proc(opfamily,
op_lefttype,
op_righttype,
BTORDER_PROC);
if (!RegProcedureIsValid(opfuncid))
elog(ERROR, "missing support function %d(%u,%u) in opfamily %u",
BTORDER_PROC, op_lefttype, op_righttype, opfamily);
/*
* rightop is the constant or variable comparison value
*/
if (rightop && IsA(rightop, RelabelType))
rightop = ((RelabelType *) rightop)->arg;
Assert(rightop != NULL);
if (IsA(rightop, Const))
{
/* OK, simple constant comparison value */
scanvalue = ((Const *) rightop)->constvalue;
if (((Const *) rightop)->constisnull)
flags |= SK_ISNULL;
}
else
{
/* Need to treat this one as a runtime key */
if (n_runtime_keys >= max_runtime_keys)
{
if (max_runtime_keys == 0)
{
max_runtime_keys = 8;
runtime_keys = (IndexRuntimeKeyInfo *)
palloc(max_runtime_keys * sizeof(IndexRuntimeKeyInfo));
}
else
{
max_runtime_keys *= 2;
runtime_keys = (IndexRuntimeKeyInfo *)
repalloc(runtime_keys, max_runtime_keys * sizeof(IndexRuntimeKeyInfo));
}
}
runtime_keys[n_runtime_keys].scan_key = this_sub_key;
runtime_keys[n_runtime_keys].key_expr =
ExecInitExpr(rightop, planstate);
runtime_keys[n_runtime_keys].key_toastable =
TypeIsToastable(op_righttype);
n_runtime_keys++;
scanvalue = (Datum) 0;
}
/*
* initialize the subsidiary scan key's fields appropriately
*/
ScanKeyEntryInitialize(this_sub_key,
flags,
varattno, /* attribute number */
op_strategy, /* op's strategy */
op_righttype, /* strategy subtype */
inputcollation, /* collation */
opfuncid, /* reg proc to use */
scanvalue); /* constant */
n_sub_key++;
}
/* Mark the last subsidiary scankey correctly */
first_sub_key[n_sub_key - 1].sk_flags |= SK_ROW_END;
/*
* We don't use ScanKeyEntryInitialize for the header because it
* isn't going to contain a valid sk_func pointer.
*/
MemSet(this_scan_key, 0, sizeof(ScanKeyData));
this_scan_key->sk_flags = SK_ROW_HEADER;
this_scan_key->sk_attno = first_sub_key->sk_attno;
this_scan_key->sk_strategy = rc->rctype;
/* sk_subtype, sk_collation, sk_func not used in a header */
this_scan_key->sk_argument = PointerGetDatum(first_sub_key);
}
else if (IsA(clause, ScalarArrayOpExpr))
{
/* indexkey op ANY (array-expression) */
ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) clause;
int flags = 0;
Datum scanvalue;
Assert(!isorderby);
Assert(saop->useOr);
opno = saop->opno;
opfuncid = saop->opfuncid;
/*
* leftop should be the index key Var, possibly relabeled
*/
leftop = (Expr *) linitial(saop->args);
if (leftop && IsA(leftop, RelabelType))
leftop = ((RelabelType *) leftop)->arg;
Assert(leftop != NULL);
if (!(IsA(leftop, Var) &&
((Var *) leftop)->varno == INDEX_VAR))
elog(ERROR, "indexqual doesn't have key on left side");
varattno = ((Var *) leftop)->varattno;
if (varattno < 1 || varattno > indnkeyatts)
elog(ERROR, "bogus index qualification");
/*
* We have to look up the operator's strategy number. This
* provides a cross-check that the operator does match the index.
*/
opfamily = index->rd_opfamily[varattno - 1];
get_op_opfamily_properties(opno, opfamily, isorderby,
&op_strategy,
&op_lefttype,
&op_righttype);
/*
* rightop is the constant or variable array value
*/
rightop = (Expr *) lsecond(saop->args);
if (rightop && IsA(rightop, RelabelType))
rightop = ((RelabelType *) rightop)->arg;
Assert(rightop != NULL);
if (index->rd_indam->amsearcharray)
{
/* Index AM will handle this like a simple operator */
flags |= SK_SEARCHARRAY;
if (IsA(rightop, Const))
{
/* OK, simple constant comparison value */
scanvalue = ((Const *) rightop)->constvalue;
if (((Const *) rightop)->constisnull)
flags |= SK_ISNULL;
}
else
{
/* Need to treat this one as a runtime key */
if (n_runtime_keys >= max_runtime_keys)
{
if (max_runtime_keys == 0)
{
max_runtime_keys = 8;
runtime_keys = (IndexRuntimeKeyInfo *)
palloc(max_runtime_keys * sizeof(IndexRuntimeKeyInfo));
}
else
{
max_runtime_keys *= 2;
runtime_keys = (IndexRuntimeKeyInfo *)
repalloc(runtime_keys, max_runtime_keys * sizeof(IndexRuntimeKeyInfo));
}
}
runtime_keys[n_runtime_keys].scan_key = this_scan_key;
runtime_keys[n_runtime_keys].key_expr =
ExecInitExpr(rightop, planstate);
/*
* Careful here: the runtime expression is not of
* op_righttype, but rather is an array of same; so
* TypeIsToastable() isn't helpful. However, we can
* assume that all array types are toastable.
*/
runtime_keys[n_runtime_keys].key_toastable = true;
n_runtime_keys++;
scanvalue = (Datum) 0;
}
}
else
{
/* Executor has to expand the array value */
array_keys[n_array_keys].scan_key = this_scan_key;
array_keys[n_array_keys].array_expr =
ExecInitExpr(rightop, planstate);
/* the remaining fields were zeroed by palloc0 */
n_array_keys++;
scanvalue = (Datum) 0;
}
/*
* initialize the scan key's fields appropriately
*/
ScanKeyEntryInitialize(this_scan_key,
flags,
varattno, /* attribute number to scan */
op_strategy, /* op's strategy */
op_righttype, /* strategy subtype */
saop->inputcollid, /* collation */
opfuncid, /* reg proc to use */
scanvalue); /* constant */
}
else if (IsA(clause, NullTest))
{
/* indexkey IS NULL or indexkey IS NOT NULL */
NullTest *ntest = (NullTest *) clause;
int flags;
Assert(!isorderby);
/*
* argument should be the index key Var, possibly relabeled
*/
leftop = ntest->arg;
if (leftop && IsA(leftop, RelabelType))
leftop = ((RelabelType *) leftop)->arg;
Assert(leftop != NULL);
if (!(IsA(leftop, Var) &&
((Var *) leftop)->varno == INDEX_VAR))
elog(ERROR, "NullTest indexqual has wrong key");
varattno = ((Var *) leftop)->varattno;
/*
* initialize the scan key's fields appropriately
*/
switch (ntest->nulltesttype)
{
case IS_NULL:
flags = SK_ISNULL | SK_SEARCHNULL;
break;
case IS_NOT_NULL:
flags = SK_ISNULL | SK_SEARCHNOTNULL;
break;
default:
elog(ERROR, "unrecognized nulltesttype: %d",
(int) ntest->nulltesttype);
flags = 0; /* keep compiler quiet */
break;
}
ScanKeyEntryInitialize(this_scan_key,
flags,
varattno, /* attribute number to scan */
InvalidStrategy, /* no strategy */
InvalidOid, /* no strategy subtype */
InvalidOid, /* no collation */
InvalidOid, /* no reg proc for this */
(Datum) 0); /* constant */
}
else
elog(ERROR, "unsupported indexqual type: %d",
(int) nodeTag(clause));
}
Assert(n_runtime_keys <= max_runtime_keys);
/* Get rid of any unused arrays */
if (n_array_keys == 0)
{
pfree(array_keys);
array_keys = NULL;
}
/*
* Return info to our caller.
*/
*scanKeys = scan_keys;
*numScanKeys = n_scan_keys;
*runtimeKeys = runtime_keys;
*numRuntimeKeys = n_runtime_keys;
if (arrayKeys)
{
*arrayKeys = array_keys;
*numArrayKeys = n_array_keys;
}
else if (n_array_keys != 0)
elog(ERROR, "ScalarArrayOpExpr index qual found where not allowed");
}
/* ----------------------------------------------------------------
* Parallel Scan Support
* ----------------------------------------------------------------
*/
/* ----------------------------------------------------------------
* ExecIndexScanEstimate
*
* Compute the amount of space we'll need in the parallel
* query DSM, and inform pcxt->estimator about our needs.
* ----------------------------------------------------------------
*/
void
ExecIndexScanEstimate(IndexScanState *node,
ParallelContext *pcxt)
{
EState *estate = node->ss.ps.state;
node->iss_PscanLen = index_parallelscan_estimate(node->iss_RelationDesc,
estate->es_snapshot);
shm_toc_estimate_chunk(&pcxt->estimator, node->iss_PscanLen);
shm_toc_estimate_keys(&pcxt->estimator, 1);
}
/* ----------------------------------------------------------------
* ExecIndexScanInitializeDSM
*
* Set up a parallel index scan descriptor.
* ----------------------------------------------------------------
*/
void
ExecIndexScanInitializeDSM(IndexScanState *node,
ParallelContext *pcxt)
{
EState *estate = node->ss.ps.state;
ParallelIndexScanDesc piscan;
piscan = shm_toc_allocate(pcxt->toc, node->iss_PscanLen);
index_parallelscan_initialize(node->ss.ss_currentRelation,
node->iss_RelationDesc,
estate->es_snapshot,
piscan);
shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, piscan);
node->iss_ScanDesc =
index_beginscan_parallel(node->ss.ss_currentRelation,
node->iss_RelationDesc,
node->iss_NumScanKeys,
node->iss_NumOrderByKeys,
piscan);
/*
* If no run-time keys to calculate or they are ready, go ahead and pass
* the scankeys to the index AM.
*/
if (node->iss_NumRuntimeKeys == 0 || node->iss_RuntimeKeysReady)
index_rescan(node->iss_ScanDesc,
node->iss_ScanKeys, node->iss_NumScanKeys,
node->iss_OrderByKeys, node->iss_NumOrderByKeys);
}
/* ----------------------------------------------------------------
* ExecIndexScanReInitializeDSM
*
* Reset shared state before beginning a fresh scan.
* ----------------------------------------------------------------
*/
void
ExecIndexScanReInitializeDSM(IndexScanState *node,
ParallelContext *pcxt)
{
index_parallelrescan(node->iss_ScanDesc);
}
/* ----------------------------------------------------------------
* ExecIndexScanInitializeWorker
*
* Copy relevant information from TOC into planstate.
* ----------------------------------------------------------------
*/
void
ExecIndexScanInitializeWorker(IndexScanState *node,
ParallelWorkerContext *pwcxt)
{
ParallelIndexScanDesc piscan;
piscan = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
node->iss_ScanDesc =
index_beginscan_parallel(node->ss.ss_currentRelation,
node->iss_RelationDesc,
node->iss_NumScanKeys,
node->iss_NumOrderByKeys,
piscan);
/*
* If no run-time keys to calculate or they are ready, go ahead and pass
* the scankeys to the index AM.
*/
if (node->iss_NumRuntimeKeys == 0 || node->iss_RuntimeKeysReady)
index_rescan(node->iss_ScanDesc,
node->iss_ScanKeys, node->iss_NumScanKeys,
node->iss_OrderByKeys, node->iss_NumOrderByKeys);
}
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