From 1281e9e9c9393efc80442bf4ec98c8f91664682f Mon Sep 17 00:00:00 2001 From: Nitin Motiani Date: Fri, 12 Sep 2025 08:49:07 +0000 Subject: [PATCH v3] Fix "unexpected zero page" in pgstattuple for hash and gist indexes * pgstattuple calls check functions for all the pages in hash and gist indexes. These calls are made from pgstat_hash_page() and pgstat_gist_page(). For zero pages, these call lead to ERRCODE_INDEX_CORRUPTED. * Since zero pages are normal after a crash, these errors are false alarms. pgstat_btree_page() avoids these errors by not running these checks. * In this patch, we do the same for gist and hash indexes. For hash index, ReadBufferExtended() replaces _hash_getbuf_with_strategy() which was calling _hash_check_page(). Instead we do the required check for special size explicitly for the non-PageIsNew() cases. * Similarly for gist index, we remove gistcheckpage() and explicitly checks the special size for the non-PageIsNew() cases before checking if the page is a leaf. * The comments in the else clauses have been updated accordingly. Reported-by: Noah Misch --- contrib/pgstattuple/pgstattuple.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c index b5de68b7232..2511edccecc 100644 --- a/contrib/pgstattuple/pgstattuple.c +++ b/contrib/pgstattuple/pgstattuple.c @@ -424,7 +424,7 @@ pgstat_btree_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno, /* fully empty page */ stat->free_space += BLCKSZ; } - else + else if (PageGetSpecialSize(page) == MAXALIGN(sizeof(BTPageOpaqueData))) { BTPageOpaque opaque; @@ -458,10 +458,16 @@ pgstat_hash_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno, Buffer buf; Page page; - buf = _hash_getbuf_with_strategy(rel, blkno, HASH_READ, 0, bstrategy); + buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy); + LockBuffer(buf, HASH_READ); page = BufferGetPage(buf); - if (PageGetSpecialSize(page) == MAXALIGN(sizeof(HashPageOpaqueData))) + if (PageIsNew(page)) + { + /* fully empty page */ + stat->free_space += BLCKSZ; + } + else if (PageGetSpecialSize(page) == MAXALIGN(sizeof(HashPageOpaqueData))) { HashPageOpaque opaque; @@ -502,10 +508,14 @@ pgstat_gist_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno, buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy); LockBuffer(buf, GIST_SHARE); - gistcheckpage(rel, buf); page = BufferGetPage(buf); - - if (GistPageIsLeaf(page)) + if (PageIsNew(page)) + { + /* fully empty page */ + stat->free_space += BLCKSZ; + } + else if (PageGetSpecialSize(page) == MAXALIGN(sizeof(GISTPageOpaqueData)) && + GistPageIsLeaf(page)) { pgstat_index_page(stat, page, FirstOffsetNumber, PageGetMaxOffsetNumber(page)); -- 2.51.0.618.g983fd99d29-goog