/*-------------------------------------------------------------------------- * ginblock.h * details of structures stored in GIN index blocks * * Copyright (c) 2006-2021, PostgreSQL Global Development Group * * src/include/access/ginblock.h *-------------------------------------------------------------------------- */ #ifndef GINBLOCK_H #define GINBLOCK_H #include "access/transam.h" #include "storage/block.h" #include "storage/bufpage.h" #include "storage/itemptr.h" #include "storage/off.h" /* * Page opaque data in an inverted index page. * * Note: GIN does not include a page ID word as do the other index types. * This is OK because the opaque data is only 8 bytes and so can be reliably * distinguished by size. Revisit this if the size ever increases. * Further note: as of 9.2, SP-GiST also uses 8-byte special space, as does * BRIN as of 9.5. This is still OK, as long as GIN isn't using all of the * high-order bits in its flags word, because that way the flags word cannot * match the page IDs used by SP-GiST and BRIN. */ typedef struct GinPageOpaqueData { BlockNumber rightlink; /* next page if any */ OffsetNumber maxoff; /* number of PostingItems on GIN_DATA & * ~GIN_LEAF page. On GIN_LIST page, number of * heap tuples. */ uint16 flags; /* see bit definitions below */ } GinPageOpaqueData; typedef GinPageOpaqueData *GinPageOpaque; #define GIN_DATA (1 << 0) #define GIN_LEAF (1 << 1) #define GIN_DELETED (1 << 2) #define GIN_META (1 << 3) #define GIN_LIST (1 << 4) #define GIN_LIST_FULLROW (1 << 5) /* makes sense only on GIN_LIST page */ #define GIN_INCOMPLETE_SPLIT (1 << 6) /* page was split, but parent not * updated */ #define GIN_COMPRESSED (1 << 7) /* Page numbers of fixed-location pages */ #define GIN_METAPAGE_BLKNO (0) #define GIN_ROOT_BLKNO (1) typedef struct GinMetaPageData { /* * Pointers to head and tail of pending list, which consists of GIN_LIST * pages. These store fast-inserted entries that haven't yet been moved * into the regular GIN structure. */ BlockNumber head; BlockNumber tail; /* * Free space in bytes in the pending list's tail page. */ uint32 tailFreeSize; /* * We store both number of pages and number of heap tuples that are in the * pending list. */ BlockNumber nPendingPages; int64 nPendingHeapTuples; /* * Statistics for planner use (accurate as of last VACUUM) */ BlockNumber nTotalPages; BlockNumber nEntryPages; BlockNumber nDataPages; int64 nEntries; /* * GIN version number (ideally this should have been at the front, but too * late now. Don't move it!) * * Currently 2 (for indexes initialized in 9.4 or later) * * Version 1 (indexes initialized in version 9.1, 9.2 or 9.3), is * compatible, but may contain uncompressed posting tree (leaf) pages and * posting lists. They will be converted to compressed format when * modified. * * Version 0 (indexes initialized in 9.0 or before) is compatible but may * be missing null entries, including both null keys and placeholders. * Reject full-index-scan attempts on such indexes. */ int32 ginVersion; } GinMetaPageData; #define GIN_CURRENT_VERSION 2 #define GinPageGetMeta(p) \ ((GinMetaPageData *) PageGetContents(p)) /* * Macros for accessing a GIN index page's opaque data */ #define GinPageGetOpaque(page) ( (GinPageOpaque) PageGetSpecialPointer(page) ) #define GinPageIsLeaf(page) ( (GinPageGetOpaque(page)->flags & GIN_LEAF) != 0 ) #define GinPageSetLeaf(page) ( GinPageGetOpaque(page)->flags |= GIN_LEAF ) #define GinPageSetNonLeaf(page) ( GinPageGetOpaque(page)->flags &= ~GIN_LEAF ) #define GinPageIsData(page) ( (GinPageGetOpaque(page)->flags & GIN_DATA) != 0 ) #define GinPageSetData(page) ( GinPageGetOpaque(page)->flags |= GIN_DATA ) #define GinPageIsList(page) ( (GinPageGetOpaque(page)->flags & GIN_LIST) != 0 ) #define GinPageSetList(page) ( GinPageGetOpaque(page)->flags |= GIN_LIST ) #define GinPageHasFullRow(page) ( (GinPageGetOpaque(page)->flags & GIN_LIST_FULLROW) != 0 ) #define GinPageSetFullRow(page) ( GinPageGetOpaque(page)->flags |= GIN_LIST_FULLROW ) #define GinPageIsCompressed(page) ( (GinPageGetOpaque(page)->flags & GIN_COMPRESSED) != 0 ) #define GinPageSetCompressed(page) ( GinPageGetOpaque(page)->flags |= GIN_COMPRESSED ) #define GinPageIsDeleted(page) ( (GinPageGetOpaque(page)->flags & GIN_DELETED) != 0 ) #define GinPageSetDeleted(page) ( GinPageGetOpaque(page)->flags |= GIN_DELETED) #define GinPageSetNonDeleted(page) ( GinPageGetOpaque(page)->flags &= ~GIN_DELETED) #define GinPageIsIncompleteSplit(page) ( (GinPageGetOpaque(page)->flags & GIN_INCOMPLETE_SPLIT) != 0 ) #define GinPageRightMost(page) ( GinPageGetOpaque(page)->rightlink == InvalidBlockNumber) /* * We should reclaim deleted page only once every transaction started before * its deletion is over. */ #define GinPageGetDeleteXid(page) ( ((PageHeader) (page))->pd_prune_xid ) #define GinPageSetDeleteXid(page, xid) ( ((PageHeader) (page))->pd_prune_xid = xid) extern bool GinPageIsRecyclable(Page page); /* * We use our own ItemPointerGet(BlockNumber|OffsetNumber) * to avoid Asserts, since sometimes the ip_posid isn't "valid" */ #define GinItemPointerGetBlockNumber(pointer) \ (ItemPointerGetBlockNumberNoCheck(pointer)) #define GinItemPointerGetOffsetNumber(pointer) \ (ItemPointerGetOffsetNumberNoCheck(pointer)) #define GinItemPointerSetBlockNumber(pointer, blkno) \ (ItemPointerSetBlockNumber((pointer), (blkno))) #define GinItemPointerSetOffsetNumber(pointer, offnum) \ (ItemPointerSetOffsetNumber((pointer), (offnum))) /* * Special-case item pointer values needed by the GIN search logic. * MIN: sorts less than any valid item pointer * MAX: sorts greater than any valid item pointer * LOSSY PAGE: indicates a whole heap page, sorts after normal item * pointers for that page * Note that these are all distinguishable from an "invalid" item pointer * (which is InvalidBlockNumber/0) as well as from all normal item * pointers (which have item numbers in the range 1..MaxHeapTuplesPerPage). */ #define ItemPointerSetMin(p) \ ItemPointerSet((p), (BlockNumber)0, (OffsetNumber)0) #define ItemPointerIsMin(p) \ (GinItemPointerGetOffsetNumber(p) == (OffsetNumber)0 && \ GinItemPointerGetBlockNumber(p) == (BlockNumber)0) #define ItemPointerSetMax(p) \ ItemPointerSet((p), InvalidBlockNumber, (OffsetNumber)0xffff) #define ItemPointerSetLossyPage(p, b) \ ItemPointerSet((p), (b), (OffsetNumber)0xffff) #define ItemPointerIsLossyPage(p) \ (GinItemPointerGetOffsetNumber(p) == (OffsetNumber)0xffff && \ GinItemPointerGetBlockNumber(p) != InvalidBlockNumber) /* * Posting item in a non-leaf posting-tree page */ typedef struct { /* We use BlockIdData not BlockNumber to avoid padding space wastage */ BlockIdData child_blkno; ItemPointerData key; } PostingItem; #define PostingItemGetBlockNumber(pointer) \ BlockIdGetBlockNumber(&(pointer)->child_blkno) #define PostingItemSetBlockNumber(pointer, blockNumber) \ BlockIdSet(&((pointer)->child_blkno), (blockNumber)) /* * Category codes to distinguish placeholder nulls from ordinary NULL keys. * * The first two code values were chosen to be compatible with the usual usage * of bool isNull flags. However, casting between bool and GinNullCategory is * risky because of the possibility of different bit patterns and type sizes, * so it is no longer done. * * GIN_CAT_EMPTY_QUERY is never stored in the index; and notice that it is * chosen to sort before not after regular key values. */ typedef signed char GinNullCategory; #define GIN_CAT_NORM_KEY 0 /* normal, non-null key value */ #define GIN_CAT_NULL_KEY 1 /* null key value */ #define GIN_CAT_EMPTY_ITEM 2 /* placeholder for zero-key item */ #define GIN_CAT_NULL_ITEM 3 /* placeholder for null item */ #define GIN_CAT_EMPTY_QUERY (-1) /* placeholder for full-scan query */ /* * Access macros for null category byte in entry tuples */ #define GinCategoryOffset(itup,ginstate) \ (IndexInfoFindDataOffset((itup)->t_info) + \ ((ginstate)->oneCol ? 0 : sizeof(int16))) #define GinGetNullCategory(itup,ginstate) \ (*((GinNullCategory *) ((char*)(itup) + GinCategoryOffset(itup,ginstate)))) #define GinSetNullCategory(itup,ginstate,c) \ (*((GinNullCategory *) ((char*)(itup) + GinCategoryOffset(itup,ginstate))) = (c)) /* * Access macros for leaf-page entry tuples (see discussion in README) */ #define GinGetNPosting(itup) GinItemPointerGetOffsetNumber(&(itup)->t_tid) #define GinSetNPosting(itup,n) ItemPointerSetOffsetNumber(&(itup)->t_tid,n) #define GIN_TREE_POSTING ((OffsetNumber)0xffff) #define GinIsPostingTree(itup) (GinGetNPosting(itup) == GIN_TREE_POSTING) #define GinSetPostingTree(itup, blkno) ( GinSetNPosting((itup),GIN_TREE_POSTING), ItemPointerSetBlockNumber(&(itup)->t_tid, blkno) ) #define GinGetPostingTree(itup) GinItemPointerGetBlockNumber(&(itup)->t_tid) #define GIN_ITUP_COMPRESSED (1U << 31) #define GinGetPostingOffset(itup) (GinItemPointerGetBlockNumber(&(itup)->t_tid) & (~GIN_ITUP_COMPRESSED)) #define GinSetPostingOffset(itup,n) ItemPointerSetBlockNumber(&(itup)->t_tid,(n)|GIN_ITUP_COMPRESSED) #define GinGetPosting(itup) ((Pointer) ((char*)(itup) + GinGetPostingOffset(itup))) #define GinItupIsCompressed(itup) ((GinItemPointerGetBlockNumber(&(itup)->t_tid) & GIN_ITUP_COMPRESSED) != 0) /* * Maximum size of an item on entry tree page. Make sure that we fit at least * three items on each page. (On regular B-tree indexes, we must fit at least * three items: two data items and the "high key". In GIN entry tree, we don't * currently store the high key explicitly, we just use the rightmost item on * the page, so it would actually be enough to fit two items.) */ #define GinMaxItemSize \ Min(INDEX_SIZE_MASK, \ MAXALIGN_DOWN(((BLCKSZ - \ MAXALIGN(SizeOfPageHeaderData + 3 * sizeof(ItemIdData)) - \ MAXALIGN(sizeof(GinPageOpaqueData))) / 3))) /* * Access macros for non-leaf entry tuples */ #define GinGetDownlink(itup) GinItemPointerGetBlockNumber(&(itup)->t_tid) #define GinSetDownlink(itup,blkno) ItemPointerSet(&(itup)->t_tid, blkno, InvalidOffsetNumber) /* * Data (posting tree) pages * * Posting tree pages don't store regular tuples. Non-leaf pages contain * PostingItems, which are pairs of ItemPointers and child block numbers. * Leaf pages contain GinPostingLists and an uncompressed array of item * pointers. * * In a leaf page, the compressed posting lists are stored after the regular * page header, one after each other. Although we don't store regular tuples, * pd_lower is used to indicate the end of the posting lists. After that, free * space follows. This layout is compatible with the "standard" heap and * index page layout described in bufpage.h, so that we can e.g set buffer_std * when writing WAL records. * * In the special space is the GinPageOpaque struct. */ #define GinDataLeafPageGetPostingList(page) \ (GinPostingList *) ((PageGetContents(page) + MAXALIGN(sizeof(ItemPointerData)))) #define GinDataLeafPageGetPostingListSize(page) \ (((PageHeader) page)->pd_lower - MAXALIGN(SizeOfPageHeaderData) - MAXALIGN(sizeof(ItemPointerData))) #define GinDataLeafPageIsEmpty(page) \ (GinPageIsCompressed(page) ? (GinDataLeafPageGetPostingListSize(page) == 0) : (GinPageGetOpaque(page)->maxoff < FirstOffsetNumber)) #define GinDataLeafPageGetFreeSpace(page) PageGetExactFreeSpace(page) #define GinDataPageGetRightBound(page) ((ItemPointer) PageGetContents(page)) /* * Pointer to the data portion of a posting tree page. For internal pages, * that's the beginning of the array of PostingItems. For compressed leaf * pages, the first compressed posting list. For uncompressed (pre-9.4) leaf * pages, it's the beginning of the ItemPointer array. */ #define GinDataPageGetData(page) \ (PageGetContents(page) + MAXALIGN(sizeof(ItemPointerData))) /* non-leaf pages contain PostingItems */ #define GinDataPageGetPostingItem(page, i) \ ((PostingItem *) (GinDataPageGetData(page) + ((i)-1) * sizeof(PostingItem))) /* * Note: there is no GinDataPageGetDataSize macro, because before version * 9.4, we didn't set pd_lower on data pages. There can be pages in the index * that were binary-upgraded from earlier versions and still have an invalid * pd_lower, so we cannot trust it in general. Compressed posting tree leaf * pages are new in 9.4, however, so we can trust them; see * GinDataLeafPageGetPostingListSize. */ #define GinDataPageSetDataSize(page, size) \ { \ Assert(size <= GinDataPageMaxDataSize); \ ((PageHeader) page)->pd_lower = (size) + MAXALIGN(SizeOfPageHeaderData) + MAXALIGN(sizeof(ItemPointerData)); \ } #define GinNonLeafDataPageGetFreeSpace(page) \ (GinDataPageMaxDataSize - \ GinPageGetOpaque(page)->maxoff * sizeof(PostingItem)) #define GinDataPageMaxDataSize \ (BLCKSZ - MAXALIGN(SizeOfPageHeaderData) \ - MAXALIGN(sizeof(ItemPointerData)) \ - MAXALIGN(sizeof(GinPageOpaqueData))) /* * List pages */ #define GinListPageSize \ ( BLCKSZ - SizeOfPageHeaderData - MAXALIGN(sizeof(GinPageOpaqueData)) ) /* * A compressed posting list. * * Note: This requires 2-byte alignment. */ typedef struct { ItemPointerData first; /* first item in this posting list (unpacked) */ uint16 nbytes; /* number of bytes that follow */ unsigned char bytes[FLEXIBLE_ARRAY_MEMBER]; /* varbyte encoded items */ } GinPostingList; #define SizeOfGinPostingList(plist) (offsetof(GinPostingList, bytes) + SHORTALIGN((plist)->nbytes) ) #define GinNextPostingListSegment(cur) ((GinPostingList *) (((char *) (cur)) + SizeOfGinPostingList((cur)))) #endif /* GINBLOCK_H */