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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) 1996-2011, 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
* ExecInitIndexScan creates and initializes state info.
* ExecReScanIndexScan rescans the indexed relation.
* ExecEndIndexScan releases all storage.
* ExecIndexMarkPos marks scan position.
* ExecIndexRestrPos restores scan position.
*/
#include "postgres.h"
#include "access/nbtree.h"
#include "access/relscan.h"
#include "executor/execdebug.h"
#include "executor/nodeIndexscan.h"
#include "optimizer/clauses.h"
#include "utils/array.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
static TupleTableSlot *IndexNext(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;
HeapTuple tuple;
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;
/*
* ok, now that we have what we need, fetch the next tuple.
*/
while ((tuple = index_getnext(scandesc, direction)) != NULL)
{
/*
* Store the scanned tuple in the scan tuple slot of the scan state.
* Note: we pass 'false' because tuples returned by amgetnext are
* pointers onto disk pages and must not be pfree()'d.
*/
ExecStoreTuple(tuple, /* tuple to store */
slot, /* slot to store in */
scandesc->xs_cbuf, /* buffer containing tuple */
false); /* don't pfree */
/*
* If the index was lossy, we have to recheck the index quals using
* the fetched tuple.
*/
if (scandesc->xs_recheck)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->indexqualorig, econtext, false))
{
/* 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..
*/
return ExecClearTuple(slot);
}
/*
* 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;
ResetExprContext(econtext);
return ExecQual(node->indexqualorig, econtext, false);
}
/* ----------------------------------------------------------------
* ExecIndexScan(node)
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecIndexScan(IndexScanState *node)
{
/*
* 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);
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;
/* reset index scan */
index_rescan(node->iss_ScanDesc,
node->iss_ScanKeys, node->iss_NumScanKeys,
node->iss_OrderByKeys, node->iss_NumOrderByKeys);
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,
NULL);
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,
NULL);
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;
Relation relation;
/*
* extract information from the node
*/
indexRelationDesc = node->iss_RelationDesc;
indexScanDesc = node->iss_ScanDesc;
relation = node->ss.ss_currentRelation;
/*
* 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
*/
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);
/*
* close the heap relation.
*/
ExecCloseScanRelation(relation);
}
/* ----------------------------------------------------------------
* ExecIndexMarkPos
* ----------------------------------------------------------------
*/
void
ExecIndexMarkPos(IndexScanState *node)
{
index_markpos(node->iss_ScanDesc);
}
/* ----------------------------------------------------------------
* ExecIndexRestrPos
* ----------------------------------------------------------------
*/
void
ExecIndexRestrPos(IndexScanState *node)
{
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;
bool relistarget;
/*
* create state structure
*/
indexstate = makeNode(IndexScanState);
indexstate->ss.ps.plan = (Plan *) node;
indexstate->ss.ps.state = estate;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &indexstate->ss.ps);
indexstate->ss.ps.ps_TupFromTlist = false;
/*
* 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.targetlist = (List *)
ExecInitExpr((Expr *) node->scan.plan.targetlist,
(PlanState *) indexstate);
indexstate->ss.ps.qual = (List *)
ExecInitExpr((Expr *) node->scan.plan.qual,
(PlanState *) indexstate);
indexstate->indexqualorig = (List *)
ExecInitExpr((Expr *) node->indexqualorig,
(PlanState *) indexstate);
/*
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &indexstate->ss.ps);
ExecInitScanTupleSlot(estate, &indexstate->ss);
/*
* open the base relation and acquire appropriate lock on it.
*/
currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid);
indexstate->ss.ss_currentRelation = currentRelation;
indexstate->ss.ss_currentScanDesc = NULL; /* no heap scan here */
/*
* get the scan type from the relation descriptor.
*/
ExecAssignScanType(&indexstate->ss, RelationGetDescr(currentRelation));
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(&indexstate->ss.ps);
ExecAssignScanProjectionInfo(&indexstate->ss);
/*
* 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->iss_RelationDesc = index_open(node->indexid,
relistarget ? NoLock : AccessShareLock);
/*
* 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);
/*
* 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;
}
/*
* Initialize scan descriptor.
*/
indexstate->iss_ScanDesc = index_beginscan(currentRelation,
indexstate->iss_RelationDesc,
estate->es_snapshot,
indexstate->iss_NumScanKeys,
indexstate->iss_NumOrderByKeys);
/*
* If no run-time keys to calculate, go ahead and pass the scankeys to the
* index AM.
*/
if (indexstate->iss_NumRuntimeKeys == 0)
index_rescan(indexstate->iss_ScanDesc,
indexstate->iss_ScanKeys, indexstate->iss_NumScanKeys,
indexstate->iss_OrderByKeys, indexstate->iss_NumOrderByKeys);
/*
* 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
* has rd_am->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 */
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 > index->rd_index->indnatts)
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;
ListCell *largs_cell = list_head(rc->largs);
ListCell *rargs_cell = list_head(rc->rargs);
ListCell *opnos_cell = list_head(rc->opnos);
ListCell *collids_cell = list_head(rc->inputcollids);
ScanKey first_sub_key;
int n_sub_key;
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 */
while (opnos_cell != NULL)
{
ScanKey this_sub_key = &first_sub_key[n_sub_key];
int flags = SK_ROW_MEMBER;
Datum scanvalue;
Oid inputcollation;
/*
* leftop should be the index key Var, possibly relabeled
*/
leftop = (Expr *) lfirst(largs_cell);
largs_cell = lnext(largs_cell);
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
*/
opno = lfirst_oid(opnos_cell);
opnos_cell = lnext(opnos_cell);
if (index->rd_rel->relam != BTREE_AM_OID ||
varattno < 1 || varattno > index->rd_index->indnatts)
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);
inputcollation = lfirst_oid(collids_cell);
collids_cell = lnext(collids_cell);
/*
* rightop is the constant or variable comparison value
*/
rightop = (Expr *) lfirst(rargs_cell);
rargs_cell = lnext(rargs_cell);
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 > index->rd_index->indnatts)
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_am->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");
}
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