/* * 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 = ginCompareItemPointers(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); }
/* * Try to find parent for current stack position, returns correct * parent and child's offset in stack->parent. * Function should never release root page to prevent conflicts * with vacuum process */ void ginFindParents(GinBtree btree, GinBtreeStack *stack, BlockNumber rootBlkno) { Page page; Buffer buffer; BlockNumber blkno, leftmostBlkno; OffsetNumber offset; GinBtreeStack *root = stack->parent; GinBtreeStack *ptr; if (!root) { /* XLog mode... */ root = (GinBtreeStack *) palloc(sizeof(GinBtreeStack)); root->blkno = rootBlkno; root->buffer = ReadBuffer(btree->index, rootBlkno); LockBuffer(root->buffer, GIN_EXCLUSIVE); root->parent = NULL; } else { /* * find root, we should not release root page until update is * finished!! */ while (root->parent) { ReleaseBuffer(root->buffer); root = root->parent; } Assert(root->blkno == rootBlkno); Assert(BufferGetBlockNumber(root->buffer) == rootBlkno); LockBuffer(root->buffer, GIN_EXCLUSIVE); } root->off = InvalidOffsetNumber; page = BufferGetPage(root->buffer); Assert(!GinPageIsLeaf(page)); /* check trivial case */ if ((root->off = btree->findChildPtr(btree, page, stack->blkno, InvalidOffsetNumber)) != InvalidOffsetNumber) { stack->parent = root; return; } leftmostBlkno = blkno = btree->getLeftMostPage(btree, page); LockBuffer(root->buffer, GIN_UNLOCK); Assert(blkno != InvalidBlockNumber); for (;;) { buffer = ReadBuffer(btree->index, blkno); LockBuffer(buffer, GIN_EXCLUSIVE); page = BufferGetPage(buffer); if (GinPageIsLeaf(page)) elog(ERROR, "Lost path"); leftmostBlkno = btree->getLeftMostPage(btree, page); while ((offset = btree->findChildPtr(btree, page, stack->blkno, InvalidOffsetNumber)) == InvalidOffsetNumber) { blkno = GinPageGetOpaque(page)->rightlink; LockBuffer(buffer, GIN_UNLOCK); ReleaseBuffer(buffer); if (blkno == InvalidBlockNumber) break; buffer = ReadBuffer(btree->index, blkno); LockBuffer(buffer, GIN_EXCLUSIVE); page = BufferGetPage(buffer); } if (blkno != InvalidBlockNumber) { ptr = (GinBtreeStack *) palloc(sizeof(GinBtreeStack)); ptr->blkno = blkno; ptr->buffer = buffer; ptr->parent = root; /* it's may be wrong, but in next call we will * correct */ ptr->off = offset; stack->parent = ptr; return; } blkno = leftmostBlkno; } }
/* * Find correct tuple in non-leaf page. It supposed that * page correctly choosen and searching value SHOULD be on page */ static BlockNumber entryLocateEntry(GinBtree btree, GinBtreeStack *stack) { OffsetNumber low, high, maxoff; IndexTuple itup = NULL; int result; Page page = BufferGetPage(stack->buffer); Assert(!GinPageIsLeaf(page)); Assert(!GinPageIsData(page)); if (btree->fullScan) { stack->off = FirstOffsetNumber; stack->predictNumber *= PageGetMaxOffsetNumber(page); return btree->getLeftMostPage(btree, page); } low = FirstOffsetNumber; maxoff = high = PageGetMaxOffsetNumber(page); Assert(high >= low); high++; while (high > low) { OffsetNumber mid = low + ((high - low) / 2); if (mid == maxoff && GinPageRightMost(page)) /* Right infinity */ result = -1; else { itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, mid)); result = compareAttEntries(btree->ginstate, btree->entryAttnum, btree->entryValue, gintuple_get_attrnum(btree->ginstate, itup), gin_index_getattr(btree->ginstate, itup)); } if (result == 0) { stack->off = mid; Assert(GinItemPointerGetBlockNumber(&(itup)->t_tid) != GIN_ROOT_BLKNO); return GinItemPointerGetBlockNumber(&(itup)->t_tid); } else if (result > 0) low = mid + 1; else high = mid; } Assert(high >= FirstOffsetNumber && high <= maxoff); stack->off = high; itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, high)); Assert(GinItemPointerGetBlockNumber(&(itup)->t_tid) != GIN_ROOT_BLKNO); return GinItemPointerGetBlockNumber(&(itup)->t_tid); }