greenplumn spgscan 源码
greenplumn spgscan 代码
文件路径：/src/backend/access/spgist/spgscan.c
/*-------------------------------------------------------------------------
*
* spgscan.c
* routines for scanning SP-GiST indexes
*
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/access/spgist/spgscan.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/relscan.h"
#include "access/spgist_private.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "utils/datum.h"
#include "utils/float.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
typedef void (*storeRes_func) (SpGistScanOpaque so, ItemPointer heapPtr,
Datum leafValue, bool isNull, bool recheck,
bool recheckDistances, double *distances);
/*
* Pairing heap comparison function for the SpGistSearchItem queue.
* KNN-searches currently only support NULLS LAST. So, preserve this logic
* here.
*/
static int
pairingheap_SpGistSearchItem_cmp(const pairingheap_node *a,
const pairingheap_node *b, void *arg)
{
const SpGistSearchItem *sa = (const SpGistSearchItem *) a;
const SpGistSearchItem *sb = (const SpGistSearchItem *) b;
SpGistScanOpaque so = (SpGistScanOpaque) arg;
int i;
if (sa->isNull)
{
if (!sb->isNull)
return -1;
}
else if (sb->isNull)
{
return 1;
}
else
{
/* Order according to distance comparison */
for (i = 0; i < so->numberOfOrderBys; i++)
{
if (isnan(sa->distances[i]) && isnan(sb->distances[i]))
continue; /* NaN == NaN */
if (isnan(sa->distances[i]))
return -1; /* NaN > number */
if (isnan(sb->distances[i]))
return 1; /* number < NaN */
if (sa->distances[i] != sb->distances[i])
return (sa->distances[i] < sb->distances[i]) ? 1 : -1;
}
}
/* Leaf items go before inner pages, to ensure a depth-first search */
if (sa->isLeaf && !sb->isLeaf)
return 1;
if (!sa->isLeaf && sb->isLeaf)
return -1;
return 0;
}
static void
spgFreeSearchItem(SpGistScanOpaque so, SpGistSearchItem *item)
{
if (!so->state.attLeafType.attbyval &&
DatumGetPointer(item->value) != NULL)
pfree(DatumGetPointer(item->value));
if (item->traversalValue)
pfree(item->traversalValue);
pfree(item);
}
/*
* Add SpGistSearchItem to queue
*
* Called in queue context
*/
static void
spgAddSearchItemToQueue(SpGistScanOpaque so, SpGistSearchItem *item)
{
pairingheap_add(so->scanQueue, &item->phNode);
}
static SpGistSearchItem *
spgAllocSearchItem(SpGistScanOpaque so, bool isnull, double *distances)
{
/* allocate distance array only for non-NULL items */
SpGistSearchItem *item =
palloc(SizeOfSpGistSearchItem(isnull ? 0 : so->numberOfOrderBys));
item->isNull = isnull;
if (!isnull && so->numberOfOrderBys > 0)
memcpy(item->distances, distances,
so->numberOfOrderBys * sizeof(double));
return item;
}
static void
spgAddStartItem(SpGistScanOpaque so, bool isnull)
{
SpGistSearchItem *startEntry =
spgAllocSearchItem(so, isnull, so->zeroDistances);
ItemPointerSet(&startEntry->heapPtr,
isnull ? SPGIST_NULL_BLKNO : SPGIST_ROOT_BLKNO,
FirstOffsetNumber);
startEntry->isLeaf = false;
startEntry->level = 0;
startEntry->value = (Datum) 0;
startEntry->traversalValue = NULL;
startEntry->recheck = false;
startEntry->recheckDistances = false;
spgAddSearchItemToQueue(so, startEntry);
}
/*
* Initialize queue to search the root page, resetting
* any previously active scan
*/
static void
resetSpGistScanOpaque(SpGistScanOpaque so)
{
MemoryContext oldCtx;
/*
* clear traversal context before proceeding to the next scan; this must
* not happen before the freeScanStack above, else we get double-free
* crashes.
*/
MemoryContextReset(so->traversalCxt);
oldCtx = MemoryContextSwitchTo(so->traversalCxt);
/* initialize queue only for distance-ordered scans */
so->scanQueue = pairingheap_allocate(pairingheap_SpGistSearchItem_cmp, so);
if (so->searchNulls)
/* Add a work item to scan the null index entries */
spgAddStartItem(so, true);
if (so->searchNonNulls)
/* Add a work item to scan the non-null index entries */
spgAddStartItem(so, false);
MemoryContextSwitchTo(oldCtx);
if (so->numberOfOrderBys > 0)
{
/* Must pfree distances to avoid memory leak */
int i;
for (i = 0; i < so->nPtrs; i++)
if (so->distances[i])
pfree(so->distances[i]);
}
if (so->want_itup)
{
/* Must pfree reconstructed tuples to avoid memory leak */
int i;
for (i = 0; i < so->nPtrs; i++)
pfree(so->reconTups[i]);
}
so->iPtr = so->nPtrs = 0;
}
/*
* Prepare scan keys in SpGistScanOpaque from caller-given scan keys
*
* Sets searchNulls, searchNonNulls, numberOfKeys, keyData fields of *so.
*
* The point here is to eliminate null-related considerations from what the
* opclass consistent functions need to deal with. We assume all SPGiST-
* indexable operators are strict, so any null RHS value makes the scan
* condition unsatisfiable. We also pull out any IS NULL/IS NOT NULL
* conditions; their effect is reflected into searchNulls/searchNonNulls.
*/
static void
spgPrepareScanKeys(IndexScanDesc scan)
{
SpGistScanOpaque so = (SpGistScanOpaque) scan->opaque;
bool qual_ok;
bool haveIsNull;
bool haveNotNull;
int nkeys;
int i;
so->numberOfOrderBys = scan->numberOfOrderBys;
so->orderByData = scan->orderByData;
if (scan->numberOfKeys <= 0)
{
/* If no quals, whole-index scan is required */
so->searchNulls = true;
so->searchNonNulls = true;
so->numberOfKeys = 0;
return;
}
/* Examine the given quals */
qual_ok = true;
haveIsNull = haveNotNull = false;
nkeys = 0;
for (i = 0; i < scan->numberOfKeys; i++)
{
ScanKey skey = &scan->keyData[i];
if (skey->sk_flags & SK_SEARCHNULL)
haveIsNull = true;
else if (skey->sk_flags & SK_SEARCHNOTNULL)
haveNotNull = true;
else if (skey->sk_flags & SK_ISNULL)
{
/* ordinary qual with null argument - unsatisfiable */
qual_ok = false;
break;
}
else
{
/* ordinary qual, propagate into so->keyData */
so->keyData[nkeys++] = *skey;
/* this effectively creates a not-null requirement */
haveNotNull = true;
}
}
/* IS NULL in combination with something else is unsatisfiable */
if (haveIsNull && haveNotNull)
qual_ok = false;
/* Emit results */
if (qual_ok)
{
so->searchNulls = haveIsNull;
so->searchNonNulls = haveNotNull;
so->numberOfKeys = nkeys;
}
else
{
so->searchNulls = false;
so->searchNonNulls = false;
so->numberOfKeys = 0;
}
}
IndexScanDesc
spgbeginscan(Relation rel, int keysz, int orderbysz)
{
IndexScanDesc scan;
SpGistScanOpaque so;
int i;
scan = RelationGetIndexScan(rel, keysz, orderbysz);
so = (SpGistScanOpaque) palloc0(sizeof(SpGistScanOpaqueData));
if (keysz > 0)
so->keyData = (ScanKey) palloc(sizeof(ScanKeyData) * keysz);
else
so->keyData = NULL;
initSpGistState(&so->state, scan->indexRelation);
so->tempCxt = AllocSetContextCreate(CurrentMemoryContext,
"SP-GiST search temporary context",
ALLOCSET_DEFAULT_SIZES);
so->traversalCxt = AllocSetContextCreate(CurrentMemoryContext,
"SP-GiST traversal-value context",
ALLOCSET_DEFAULT_SIZES);
/* Set up indexTupDesc and xs_hitupdesc in case it's an index-only scan */
so->indexTupDesc = scan->xs_hitupdesc = RelationGetDescr(rel);
/* Allocate various arrays needed for order-by scans */
if (scan->numberOfOrderBys > 0)
{
/* This will be filled in spgrescan, but allocate the space here */
so->orderByTypes = (Oid *)
palloc(sizeof(Oid) * scan->numberOfOrderBys);
/* These arrays have constant contents, so we can fill them now */
so->zeroDistances = (double *)
palloc(sizeof(double) * scan->numberOfOrderBys);
so->infDistances = (double *)
palloc(sizeof(double) * scan->numberOfOrderBys);
for (i = 0; i < scan->numberOfOrderBys; i++)
{
so->zeroDistances[i] = 0.0;
so->infDistances[i] = get_float8_infinity();
}
scan->xs_orderbyvals = (Datum *)
palloc0(sizeof(Datum) * scan->numberOfOrderBys);
scan->xs_orderbynulls = (bool *)
palloc(sizeof(bool) * scan->numberOfOrderBys);
memset(scan->xs_orderbynulls, true,
sizeof(bool) * scan->numberOfOrderBys);
}
fmgr_info_copy(&so->innerConsistentFn,
index_getprocinfo(rel, 1, SPGIST_INNER_CONSISTENT_PROC),
CurrentMemoryContext);
fmgr_info_copy(&so->leafConsistentFn,
index_getprocinfo(rel, 1, SPGIST_LEAF_CONSISTENT_PROC),
CurrentMemoryContext);
so->indexCollation = rel->rd_indcollation[0];
scan->opaque = so;
return scan;
}
void
spgrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
ScanKey orderbys, int norderbys)
{
SpGistScanOpaque so = (SpGistScanOpaque) scan->opaque;
/* copy scankeys into local storage */
if (scankey && scan->numberOfKeys > 0)
memmove(scan->keyData, scankey,
scan->numberOfKeys * sizeof(ScanKeyData));
/* initialize order-by data if needed */
if (orderbys && scan->numberOfOrderBys > 0)
{
int i;
memmove(scan->orderByData, orderbys,
scan->numberOfOrderBys * sizeof(ScanKeyData));
for (i = 0; i < scan->numberOfOrderBys; i++)
{
ScanKey skey = &scan->orderByData[i];
/*
* Look up the datatype returned by the original ordering
* operator. SP-GiST always uses a float8 for the distance
* function, but the ordering operator could be anything else.
*
* XXX: The distance function is only allowed to be lossy if the
* ordering operator's result type is float4 or float8. Otherwise
* we don't know how to return the distance to the executor. But
* we cannot check that here, as we won't know if the distance
* function is lossy until it returns *recheck = true for the
* first time.
*/
so->orderByTypes[i] = get_func_rettype(skey->sk_func.fn_oid);
}
}
/* preprocess scankeys, set up the representation in *so */
spgPrepareScanKeys(scan);
/* set up starting queue entries */
resetSpGistScanOpaque(so);
}
void
spgendscan(IndexScanDesc scan)
{
SpGistScanOpaque so = (SpGistScanOpaque) scan->opaque;
MemoryContextDelete(so->tempCxt);
MemoryContextDelete(so->traversalCxt);
if (so->keyData)
pfree(so->keyData);
if (so->state.deadTupleStorage)
pfree(so->state.deadTupleStorage);
if (scan->numberOfOrderBys > 0)
{
pfree(so->orderByTypes);
pfree(so->zeroDistances);
pfree(so->infDistances);
pfree(scan->xs_orderbyvals);
pfree(scan->xs_orderbynulls);
}
pfree(so);
}
/*
* Leaf SpGistSearchItem constructor, called in queue context
*/
static SpGistSearchItem *
spgNewHeapItem(SpGistScanOpaque so, int level, ItemPointer heapPtr,
Datum leafValue, bool recheck, bool recheckDistances,
bool isnull, double *distances)
{
SpGistSearchItem *item = spgAllocSearchItem(so, isnull, distances);
item->level = level;
item->heapPtr = *heapPtr;
/* copy value to queue cxt out of tmp cxt */
item->value = isnull ? (Datum) 0 :
datumCopy(leafValue, so->state.attLeafType.attbyval,
so->state.attLeafType.attlen);
item->traversalValue = NULL;
item->isLeaf = true;
item->recheck = recheck;
item->recheckDistances = recheckDistances;
return item;
}
/*
* Test whether a leaf tuple satisfies all the scan keys
*
* *reportedSome is set to true if:
* the scan is not ordered AND the item satisfies the scankeys
*/
static bool
spgLeafTest(SpGistScanOpaque so, SpGistSearchItem *item,
SpGistLeafTuple leafTuple, bool isnull,
bool *reportedSome, storeRes_func storeRes)
{
Datum leafValue;
double *distances;
bool result;
bool recheck;
bool recheckDistances;
if (isnull)
{
/* Should not have arrived on a nulls page unless nulls are wanted */
Assert(so->searchNulls);
leafValue = (Datum) 0;
distances = NULL;
recheck = false;
recheckDistances = false;
result = true;
}
else
{
spgLeafConsistentIn in;
spgLeafConsistentOut out;
/* use temp context for calling leaf_consistent */
MemoryContext oldCxt = MemoryContextSwitchTo(so->tempCxt);
in.scankeys = so->keyData;
in.nkeys = so->numberOfKeys;
in.orderbys = so->orderByData;
in.norderbys = so->numberOfOrderBys;
in.reconstructedValue = item->value;
in.traversalValue = item->traversalValue;
in.level = item->level;
in.returnData = so->want_itup;
in.leafDatum = SGLTDATUM(leafTuple, &so->state);
out.leafValue = (Datum) 0;
out.recheck = false;
out.distances = NULL;
out.recheckDistances = false;
result = DatumGetBool(FunctionCall2Coll(&so->leafConsistentFn,
so->indexCollation,
PointerGetDatum(&in),
PointerGetDatum(&out)));
recheck = out.recheck;
recheckDistances = out.recheckDistances;
leafValue = out.leafValue;
distances = out.distances;
MemoryContextSwitchTo(oldCxt);
}
if (result)
{
/* item passes the scankeys */
if (so->numberOfOrderBys > 0)
{
/* the scan is ordered -> add the item to the queue */
MemoryContext oldCxt = MemoryContextSwitchTo(so->traversalCxt);
SpGistSearchItem *heapItem = spgNewHeapItem(so, item->level,
&leafTuple->heapPtr,
leafValue,
recheck,
recheckDistances,
isnull,
distances);
spgAddSearchItemToQueue(so, heapItem);
MemoryContextSwitchTo(oldCxt);
}
else
{
/* non-ordered scan, so report the item right away */
Assert(!recheckDistances);
storeRes(so, &leafTuple->heapPtr, leafValue, isnull,
recheck, false, NULL);
*reportedSome = true;
}
}
return result;
}
/* A bundle initializer for inner_consistent methods */
static void
spgInitInnerConsistentIn(spgInnerConsistentIn *in,
SpGistScanOpaque so,
SpGistSearchItem *item,
SpGistInnerTuple innerTuple)
{
in->scankeys = so->keyData;
in->orderbys = so->orderByData;
in->nkeys = so->numberOfKeys;
in->norderbys = so->numberOfOrderBys;
in->reconstructedValue = item->value;
in->traversalMemoryContext = so->traversalCxt;
in->traversalValue = item->traversalValue;
in->level = item->level;
in->returnData = so->want_itup;
in->allTheSame = innerTuple->allTheSame;
in->hasPrefix = (innerTuple->prefixSize > 0);
in->prefixDatum = SGITDATUM(innerTuple, &so->state);
in->nNodes = innerTuple->nNodes;
in->nodeLabels = spgExtractNodeLabels(&so->state, innerTuple);
}
static SpGistSearchItem *
spgMakeInnerItem(SpGistScanOpaque so,
SpGistSearchItem *parentItem,
SpGistNodeTuple tuple,
spgInnerConsistentOut *out, int i, bool isnull,
double *distances)
{
SpGistSearchItem *item = spgAllocSearchItem(so, isnull, distances);
item->heapPtr = tuple->t_tid;
item->level = out->levelAdds ? parentItem->level + out->levelAdds[i]
: parentItem->level;
/* Must copy value out of temp context */
item->value = out->reconstructedValues
? datumCopy(out->reconstructedValues[i],
so->state.attLeafType.attbyval,
so->state.attLeafType.attlen)
: (Datum) 0;
/*
* Elements of out.traversalValues should be allocated in
* in.traversalMemoryContext, which is actually a long lived context of
* index scan.
*/
item->traversalValue =
out->traversalValues ? out->traversalValues[i] : NULL;
item->isLeaf = false;
item->recheck = false;
item->recheckDistances = false;
return item;
}
static void
spgInnerTest(SpGistScanOpaque so, SpGistSearchItem *item,
SpGistInnerTuple innerTuple, bool isnull)
{
MemoryContext oldCxt = MemoryContextSwitchTo(so->tempCxt);
spgInnerConsistentOut out;
int nNodes = innerTuple->nNodes;
int i;
memset(&out, 0, sizeof(out));
if (!isnull)
{
spgInnerConsistentIn in;
spgInitInnerConsistentIn(&in, so, item, innerTuple);
/* use user-defined inner consistent method */
FunctionCall2Coll(&so->innerConsistentFn,
so->indexCollation,
PointerGetDatum(&in),
PointerGetDatum(&out));
}
else
{
/* force all children to be visited */
out.nNodes = nNodes;
out.nodeNumbers = (int *) palloc(sizeof(int) * nNodes);
for (i = 0; i < nNodes; i++)
out.nodeNumbers[i] = i;
}
/* If allTheSame, they should all or none of them match */
if (innerTuple->allTheSame && out.nNodes != 0 && out.nNodes != nNodes)
elog(ERROR, "inconsistent inner_consistent results for allTheSame inner tuple");
if (out.nNodes)
{
/* collect node pointers */
SpGistNodeTuple node;
SpGistNodeTuple *nodes = (SpGistNodeTuple *) palloc(
sizeof(SpGistNodeTuple) * nNodes);
SGITITERATE(innerTuple, i, node)
{
nodes[i] = node;
}
MemoryContextSwitchTo(so->traversalCxt);
for (i = 0; i < out.nNodes; i++)
{
int nodeN = out.nodeNumbers[i];
SpGistSearchItem *innerItem;
double *distances;
Assert(nodeN >= 0 && nodeN < nNodes);
node = nodes[nodeN];
if (!ItemPointerIsValid(&node->t_tid))
continue;
/*
* Use infinity distances if innerConsistent() failed to return
* them or if is a NULL item (their distances are really unused).
*/
distances = out.distances ? out.distances[i] : so->infDistances;
innerItem = spgMakeInnerItem(so, item, node, &out, i, isnull,
distances);
spgAddSearchItemToQueue(so, innerItem);
}
}
MemoryContextSwitchTo(oldCxt);
}
/* Returns a next item in an (ordered) scan or null if the index is exhausted */
static SpGistSearchItem *
spgGetNextQueueItem(SpGistScanOpaque so)
{
if (pairingheap_is_empty(so->scanQueue))
return NULL; /* Done when both heaps are empty */
/* Return item; caller is responsible to pfree it */
return (SpGistSearchItem *) pairingheap_remove_first(so->scanQueue);
}
enum SpGistSpecialOffsetNumbers
{
SpGistBreakOffsetNumber = InvalidOffsetNumber,
SpGistRedirectOffsetNumber = MaxOffsetNumber + 1,
SpGistErrorOffsetNumber = MaxOffsetNumber + 2
};
static OffsetNumber
spgTestLeafTuple(SpGistScanOpaque so,
SpGistSearchItem *item,
Page page, OffsetNumber offset,
bool isnull, bool isroot,
bool *reportedSome,
storeRes_func storeRes)
{
SpGistLeafTuple leafTuple = (SpGistLeafTuple)
PageGetItem(page, PageGetItemId(page, offset));
if (leafTuple->tupstate != SPGIST_LIVE)
{
if (!isroot) /* all tuples on root should be live */
{
if (leafTuple->tupstate == SPGIST_REDIRECT)
{
/* redirection tuple should be first in chain */
Assert(offset == ItemPointerGetOffsetNumber(&item->heapPtr));
/* transfer attention to redirect point */
item->heapPtr = ((SpGistDeadTuple) leafTuple)->pointer;
Assert(ItemPointerGetBlockNumber(&item->heapPtr) != SPGIST_METAPAGE_BLKNO);
return SpGistRedirectOffsetNumber;
}
if (leafTuple->tupstate == SPGIST_DEAD)
{
/* dead tuple should be first in chain */
Assert(offset == ItemPointerGetOffsetNumber(&item->heapPtr));
/* No live entries on this page */
Assert(leafTuple->nextOffset == InvalidOffsetNumber);
return SpGistBreakOffsetNumber;
}
}
/* We should not arrive at a placeholder */
elog(ERROR, "unexpected SPGiST tuple state: %d", leafTuple->tupstate);
return SpGistErrorOffsetNumber;
}
Assert(ItemPointerIsValid(&leafTuple->heapPtr));
spgLeafTest(so, item, leafTuple, isnull, reportedSome, storeRes);
return leafTuple->nextOffset;
}
/*
* Walk the tree and report all tuples passing the scan quals to the storeRes
* subroutine.
*
* If scanWholeIndex is true, we'll do just that. If not, we'll stop at the
* next page boundary once we have reported at least one tuple.
*/
static void
spgWalk(Relation index, SpGistScanOpaque so, bool scanWholeIndex,
storeRes_func storeRes, Snapshot snapshot)
{
Buffer buffer = InvalidBuffer;
bool reportedSome = false;
while (scanWholeIndex || !reportedSome)
{
SpGistSearchItem *item = spgGetNextQueueItem(so);
if (item == NULL)
break; /* No more items in queue -> done */
redirect:
/* Check for interrupts, just in case of infinite loop */
CHECK_FOR_INTERRUPTS();
if (item->isLeaf)
{
/* We store heap items in the queue only in case of ordered search */
Assert(so->numberOfOrderBys > 0);
storeRes(so, &item->heapPtr, item->value, item->isNull,
item->recheck, item->recheckDistances, item->distances);
reportedSome = true;
}
else
{
BlockNumber blkno = ItemPointerGetBlockNumber(&item->heapPtr);
OffsetNumber offset = ItemPointerGetOffsetNumber(&item->heapPtr);
Page page;
bool isnull;
if (buffer == InvalidBuffer)
{
buffer = ReadBuffer(index, blkno);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
}
else if (blkno != BufferGetBlockNumber(buffer))
{
UnlockReleaseBuffer(buffer);
buffer = ReadBuffer(index, blkno);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
}
/* else new pointer points to the same page, no work needed */
page = BufferGetPage(buffer);
TestForOldSnapshot(snapshot, index, page);
isnull = SpGistPageStoresNulls(page) ? true : false;
if (SpGistPageIsLeaf(page))
{
/* Page is a leaf - that is, all it's tuples are heap items */
OffsetNumber max = PageGetMaxOffsetNumber(page);
if (SpGistBlockIsRoot(blkno))
{
/* When root is a leaf, examine all its tuples */
for (offset = FirstOffsetNumber; offset <= max; offset++)
(void) spgTestLeafTuple(so, item, page, offset,
isnull, true,
&reportedSome, storeRes);
}
else
{
/* Normal case: just examine the chain we arrived at */
while (offset != InvalidOffsetNumber)
{
Assert(offset >= FirstOffsetNumber && offset <= max);
offset = spgTestLeafTuple(so, item, page, offset,
isnull, false,
&reportedSome, storeRes);
if (offset == SpGistRedirectOffsetNumber)
goto redirect;
}
}
}
else /* page is inner */
{
SpGistInnerTuple innerTuple = (SpGistInnerTuple)
PageGetItem(page, PageGetItemId(page, offset));
if (innerTuple->tupstate != SPGIST_LIVE)
{
if (innerTuple->tupstate == SPGIST_REDIRECT)
{
/* transfer attention to redirect point */
item->heapPtr = ((SpGistDeadTuple) innerTuple)->pointer;
Assert(ItemPointerGetBlockNumber(&item->heapPtr) !=
SPGIST_METAPAGE_BLKNO);
goto redirect;
}
elog(ERROR, "unexpected SPGiST tuple state: %d",
innerTuple->tupstate);
}
spgInnerTest(so, item, innerTuple, isnull);
}
}
/* done with this scan item */
spgFreeSearchItem(so, item);
/* clear temp context before proceeding to the next one */
MemoryContextReset(so->tempCxt);
}
if (buffer != InvalidBuffer)
UnlockReleaseBuffer(buffer);
}
/* storeRes subroutine for getbitmap case */
static void
storeBitmap(SpGistScanOpaque so, ItemPointer heapPtr,
Datum leafValue, bool isnull, bool recheck, bool recheckDistances,
double *distances)
{
Assert(!recheckDistances && !distances);
tbm_add_tuples(so->tbm, heapPtr, 1, recheck);
so->ntids++;
}
int64
spggetbitmap(IndexScanDesc scan, Node **bmNodeP)
{
TIDBitmap *tbm;
SpGistScanOpaque so = (SpGistScanOpaque) scan->opaque;
/*
* GPDB specific code. Since GPDB also support StreamBitmap
* in bitmap index. So normally we need to create specific bitmap
* node in the amgetbitmap AM.
*/
Assert(bmNodeP);
if (*bmNodeP == NULL)
{
/* XXX should we use less than work_mem for this? */
tbm = tbm_create(work_mem * 1024L, NULL);
*bmNodeP = (Node *) tbm;
}
else if (!IsA(*bmNodeP, TIDBitmap))
elog(ERROR, "non spgist bitmap");
else
tbm = (TIDBitmap *)*bmNodeP;
/* Copy want_itup to *so so we don't need to pass it around separately */
so->want_itup = false;
so->tbm = tbm;
so->ntids = 0;
spgWalk(scan->indexRelation, so, true, storeBitmap, scan->xs_snapshot);
return so->ntids;
}
/* storeRes subroutine for gettuple case */
static void
storeGettuple(SpGistScanOpaque so, ItemPointer heapPtr,
Datum leafValue, bool isnull, bool recheck, bool recheckDistances,
double *distances)
{
Assert(so->nPtrs < MaxIndexTuplesPerPage);
so->heapPtrs[so->nPtrs] = *heapPtr;
so->recheck[so->nPtrs] = recheck;
so->recheckDistances[so->nPtrs] = recheckDistances;
if (so->numberOfOrderBys > 0)
{
if (isnull)
so->distances[so->nPtrs] = NULL;
else
{
Size size = sizeof(double) * so->numberOfOrderBys;
so->distances[so->nPtrs] = memcpy(palloc(size), distances, size);
}
}
if (so->want_itup)
{
/*
* Reconstruct index data. We have to copy the datum out of the temp
* context anyway, so we may as well create the tuple here.
*/
so->reconTups[so->nPtrs] = heap_form_tuple(so->indexTupDesc,
&leafValue,
&isnull);
}
so->nPtrs++;
}
bool
spggettuple(IndexScanDesc scan, ScanDirection dir)
{
SpGistScanOpaque so = (SpGistScanOpaque) scan->opaque;
if (dir != ForwardScanDirection)
elog(ERROR, "SP-GiST only supports forward scan direction");
/* Copy want_itup to *so so we don't need to pass it around separately */
so->want_itup = scan->xs_want_itup;
for (;;)
{
if (so->iPtr < so->nPtrs)
{
/* continuing to return reported tuples */
scan->xs_heaptid = so->heapPtrs[so->iPtr];
scan->xs_recheck = so->recheck[so->iPtr];
scan->xs_hitup = so->reconTups[so->iPtr];
if (so->numberOfOrderBys > 0)
index_store_float8_orderby_distances(scan, so->orderByTypes,
so->distances[so->iPtr],
NULL,
so->recheckDistances[so->iPtr]);
so->iPtr++;
return true;
}
if (so->numberOfOrderBys > 0)
{
/* Must pfree distances to avoid memory leak */
int i;
for (i = 0; i < so->nPtrs; i++)
if (so->distances[i])
pfree(so->distances[i]);
}
if (so->want_itup)
{
/* Must pfree reconstructed tuples to avoid memory leak */
int i;
for (i = 0; i < so->nPtrs; i++)
pfree(so->reconTups[i]);
}
so->iPtr = so->nPtrs = 0;
spgWalk(scan->indexRelation, so, false, storeGettuple,
scan->xs_snapshot);
if (so->nPtrs == 0)
break; /* must have completed scan */
}
return false;
}
bool
spgcanreturn(Relation index, int attno)
{
SpGistCache *cache;
/* We can do it if the opclass config function says so */
cache = spgGetCache(index);
return cache->config.canReturnData;
}
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