/* Combiner function for rbtree.c */
static void
ginCombineData(RBNode *existing, const RBNode *newdata, void *arg)
{
EntryAccumulator *eo = (EntryAccumulator *) existing;
const EntryAccumulator *en = (const EntryAccumulator *) newdata;
BuildAccumulator *accum = (BuildAccumulator *) arg;
/*
* Note this code assumes that newdata contains only one itempointer.
*/
if (eo->number >= eo->length)
{
accum->allocatedMemory -= GetMemoryChunkSpace(eo->list);
eo->length *= 2;
eo->list = (ItemPointerData *) repalloc(eo->list,
sizeof(ItemPointerData) * eo->length);
accum->allocatedMemory += GetMemoryChunkSpace(eo->list);
}
/* If item pointers are not ordered, they will need to be sorted. */
if (eo->shouldSort == FALSE)
{
int res;
res = compareItemPointers(eo->list + eo->number - 1, en->list);
Assert(res != 0);
if (res > 0)
eo->shouldSort = TRUE;
}
eo->list[eo->number] = en->list[0];
eo->number++;
}
static int
qsortCompareItemPointers(const void *a, const void *b)
{
int res = compareItemPointers((ItemPointer) a, (ItemPointer) b);
Assert(res != 0);
return res;
}
/*
* Get heap item pointer from scan
* returns true if found
*/
static bool
scanGetItem(IndexScanDesc scan, ItemPointerData *item)
{
uint32 i;
GinScanOpaque so = (GinScanOpaque) scan->opaque;
ItemPointerSetMin(item);
for (i = 0; i < so->nkeys; i++)
{
GinScanKey key = so->keys + i;
if (keyGetItem(scan->indexRelation, &so->ginstate, so->tempCtx, key) == FALSE)
{
if (compareItemPointers(item, &key->curItem) < 0)
*item = key->curItem;
}
else
return FALSE; /* finished one of keys */
}
for (i = 1; i <= so->nkeys; i++)
{
GinScanKey key = so->keys + i - 1;
for (;;)
{
int cmp = compareItemPointers(item, &key->curItem);
if (cmp == 0)
break;
else if (cmp > 0)
{
if (keyGetItem(scan->indexRelation, &so->ginstate, so->tempCtx, key) == TRUE)
return FALSE; /* finished one of keys */
}
else
{ /* returns to begin */
*item = key->curItem;
i = 0;
break;
}
}
}
return TRUE;
}
/*
* Checks, should we move to right link...
* Compares inserting itemp pointer with right bound of current page
*/
static bool
dataIsMoveRight(GinBtree btree, Page page)
{
ItemPointer iptr = GinDataPageGetRightBound(page);
if (GinPageRightMost(page))
return FALSE;
return (compareItemPointers(btree->items + btree->curitem, iptr) > 0) ? TRUE : FALSE;
}
/*
* Searches correct position for value on leaf page.
* Page should be correctly chosen.
* Returns true if value found on page.
*/
static bool
dataLocateLeafItem(GinBtree btree, GinBtreeStack *stack)
{
Page page = BufferGetPage(stack->buffer);
OffsetNumber low,
high;
int result;
Assert(GinPageIsLeaf(page));
Assert(GinPageIsData(page));
if (btree->fullScan)
{
stack->off = FirstOffsetNumber;
return TRUE;
}
low = FirstOffsetNumber;
high = GinPageGetOpaque(page)->maxoff;
if (high < low)
{
stack->off = FirstOffsetNumber;
return false;
}
high++;
while (high > low)
{
OffsetNumber mid = low + ((high - low) / 2);
result = compareItemPointers(btree->items + btree->curitem, (ItemPointer) GinDataPageGetItem(page, mid));
if (result == 0)
{
stack->off = mid;
return true;
}
else if (result > 0)
low = mid + 1;
else
high = mid;
}
stack->off = high;
return false;
}
/*
* Merge two ordered array of itempointer
*/
void
MergeItemPointers(ItemPointerData *dst, ItemPointerData *a, uint32 na, ItemPointerData *b, uint32 nb)
{
ItemPointerData *dptr = dst;
ItemPointerData *aptr = a,
*bptr = b;
while (aptr - a < na && bptr - b < nb)
{
if (compareItemPointers(aptr, bptr) > 0)
*dptr++ = *bptr++;
else
*dptr++ = *aptr++;
}
while (aptr - a < na)
*dptr++ = *aptr++;
while (bptr - b < nb)
*dptr++ = *bptr++;
}
static bool
findItemInPage(Page page, ItemPointer item, OffsetNumber *off)
{
OffsetNumber maxoff = GinPageGetOpaque(page)->maxoff;
int res;
if ( GinPageGetOpaque(page)->flags & GIN_DELETED )
/* page was deleted by concurrent vacuum */
return false;
/*
* scan page to find equal or first greater value
*/
for (*off = FirstOffsetNumber; *off <= maxoff; (*off)++)
{
res = compareItemPointers(item, (ItemPointer) GinDataPageGetItem(page, *off));
if (res <= 0)
return true;
}
return false;
}
/*
* Stores heap item pointer. For robust, it checks that
* item pointer are ordered
*/
static void
ginInsertData(BuildAccumulator *accum, EntryAccumulator *entry, ItemPointer heapptr)
{
if (entry->number >= entry->length)
{
accum->allocatedMemory += sizeof(ItemPointerData) * entry->length;
entry->length *= 2;
entry->list = (ItemPointerData *) repalloc(entry->list,
sizeof(ItemPointerData) * entry->length);
}
if (entry->shouldSort == FALSE)
{
int res = compareItemPointers(entry->list + entry->number - 1, heapptr);
Assert(res != 0);
if (res > 0)
entry->shouldSort = TRUE;
}
entry->list[entry->number] = *heapptr;
entry->number++;
}
/*
* Find correct PostingItem in non-leaf page. It supposed that page
* correctly chosen and searching value SHOULD be on page
*/
static BlockNumber
dataLocateItem(GinBtree btree, GinBtreeStack *stack)
{
OffsetNumber low,
high,
maxoff;
PostingItem *pitem = NULL;
int result;
Page page = BufferGetPage(stack->buffer);
Assert(!GinPageIsLeaf(page));
Assert(GinPageIsData(page));
if (btree->fullScan)
{
stack->off = FirstOffsetNumber;
stack->predictNumber *= GinPageGetOpaque(page)->maxoff;
return btree->getLeftMostPage(btree, page);
}
low = FirstOffsetNumber;
maxoff = high = GinPageGetOpaque(page)->maxoff;
Assert(high >= low);
high++;
while (high > low)
{
OffsetNumber mid = low + ((high - low) / 2);
pitem = (PostingItem *) GinDataPageGetItem(page, mid);
if (mid == maxoff)
/*
* Right infinity, page already correctly chosen with a help of
* dataIsMoveRight
*/
result = -1;
else
{
pitem = (PostingItem *) GinDataPageGetItem(page, mid);
result = compareItemPointers(btree->items + btree->curitem, &(pitem->key));
}
if (result == 0)
{
stack->off = mid;
return PostingItemGetBlockNumber(pitem);
}
else if (result > 0)
low = mid + 1;
else
high = mid;
}
Assert(high >= FirstOffsetNumber && high <= maxoff);
stack->off = high;
pitem = (PostingItem *) GinDataPageGetItem(page, high);
return PostingItemGetBlockNumber(pitem);
}
/*
* Sets key->curItem to new found heap item pointer for one scan key
* returns isFinished!
*/
static bool
keyGetItem(Relation index, GinState *ginstate, MemoryContext tempCtx, GinScanKey key)
{
uint32 i;
GinScanEntry entry;
bool res;
MemoryContext oldCtx;
if (key->isFinished)
return TRUE;
do
{
/*
* move forward from previously value and set new curItem, which is
* minimal from entries->curItems
*/
ItemPointerSetMax(&key->curItem);
for (i = 0; i < key->nentries; i++)
{
entry = key->scanEntry + i;
if (key->entryRes[i])
{
if (entry->isFinished == FALSE && entryGetItem(index, entry) == FALSE)
{
if (compareItemPointers(&entry->curItem, &key->curItem) < 0)
key->curItem = entry->curItem;
}
else
key->entryRes[i] = FALSE;
}
else if (entry->isFinished == FALSE)
{
if (compareItemPointers(&entry->curItem, &key->curItem) < 0)
key->curItem = entry->curItem;
}
}
if (ItemPointerIsMax(&key->curItem))
{
/* all entries are finished */
key->isFinished = TRUE;
return TRUE;
}
if (key->nentries == 1)
{
/* we can do not call consistentFn !! */
key->entryRes[0] = TRUE;
return FALSE;
}
/* setting up array for consistentFn */
for (i = 0; i < key->nentries; i++)
{
entry = key->scanEntry + i;
if (entry->isFinished == FALSE && compareItemPointers(&entry->curItem, &key->curItem) == 0)
key->entryRes[i] = TRUE;
else
key->entryRes[i] = FALSE;
}
oldCtx = MemoryContextSwitchTo(tempCtx);
res = DatumGetBool(FunctionCall3(
&ginstate->consistentFn,
PointerGetDatum(key->entryRes),
UInt16GetDatum(key->strategy),
key->query
));
MemoryContextSwitchTo(oldCtx);
MemoryContextReset(tempCtx);
} while (!res);
return FALSE;
}
/*
* Gets next ItemPointer from PostingTree. Note, that we copy
* page into GinScanEntry->list array and unlock page, but keep it pinned
* to prevent interference with vacuum
*/
static void
entryGetNextItem(Relation index, GinScanEntry entry)
{
Page page;
BlockNumber blkno;
for(;;)
{
entry->offset++;
if (entry->offset <= entry->nlist)
{
entry->curItem = entry->list[entry->offset - 1];
return;
}
LockBuffer(entry->buffer, GIN_SHARE);
page = BufferGetPage(entry->buffer);
for(;;)
{
/*
* It's needed to go by right link. During that we should refind
* first ItemPointer greater that stored
*/
blkno = GinPageGetOpaque(page)->rightlink;
LockBuffer(entry->buffer, GIN_UNLOCK);
if (blkno == InvalidBlockNumber)
{
ReleaseBuffer(entry->buffer);
ItemPointerSet(&entry->curItem, InvalidBlockNumber, InvalidOffsetNumber);
entry->buffer = InvalidBuffer;
entry->isFinished = TRUE;
return;
}
entry->buffer = ReleaseAndReadBuffer(entry->buffer, index, blkno);
LockBuffer(entry->buffer, GIN_SHARE);
page = BufferGetPage(entry->buffer);
entry->offset = InvalidOffsetNumber;
if (!ItemPointerIsValid(&entry->curItem) || findItemInPage(page, &entry->curItem, &entry->offset))
{
/*
* Found position equal to or greater than stored
*/
entry->nlist = GinPageGetOpaque(page)->maxoff;
memcpy( entry->list, GinDataPageGetItem(page, FirstOffsetNumber),
GinPageGetOpaque(page)->maxoff * sizeof(ItemPointerData) );
LockBuffer(entry->buffer, GIN_UNLOCK);
if ( !ItemPointerIsValid(&entry->curItem) ||
compareItemPointers( &entry->curItem, entry->list + entry->offset - 1 ) == 0 )
{
/*
* First pages are deleted or empty, or we found exact position,
* so break inner loop and continue outer one.
*/
break;
}
/*
* Find greater than entry->curItem position, store it.
*/
entry->curItem = entry->list[entry->offset - 1];
return;
}
}
}
}
