From 68d9662be1c4b705123a0e292974fb4be661294c Mon Sep 17 00:00:00 2001 From: Melanie Plageman <melanieplageman@gmail.com> Date: Wed, 18 Dec 2024 11:47:38 -0500 Subject: [PATCH] Make rs_cindex and rs_ntuples unsigned HeapScanDescData.rs_cindex and rs_ntuples can't be less than 0. All scan types using the heap scan descriptor expect these values to be >= 0. Make that expectation clear by making rs_cindex and rs_ntuples unsigned. Also remove the test in heapam_scan_bitmap_next_tuple() that checks if rs_cindex < 0. This was never true, but now that rs_cindex is unsigned, it makes even less sense. While we are at it, initialize both rs_cindex and rs_ntuples to 0 in initscan(). Author: Melanie Plageman Reviewed-by: Dilip Kumar Discussion: https://postgr.es/m/CAAKRu_ZxF8cDCM_BFi_L-t%3DRjdCZYP1usd1Gd45mjHfZxm0nZw%40mail.gmail.com --- src/backend/access/heap/heapam.c | 7 +++++-- src/backend/access/heap/heapam_handler.c | 2 +- src/include/access/heapam.h | 4 ++-- 3 files changed, 8 insertions(+), 5 deletions(-) diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index d00300c5dcb..6cdc68d981a 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -378,6 +378,8 @@ initscan(HeapScanDesc scan, ScanKey key, bool keep_startblock) ItemPointerSetInvalid(&scan->rs_ctup.t_self); scan->rs_cbuf = InvalidBuffer; scan->rs_cblock = InvalidBlockNumber; + scan->rs_ntuples = 0; + scan->rs_cindex = 0; /* * Initialize to ForwardScanDirection because it is most common and @@ -943,8 +945,8 @@ heapgettup_pagemode(HeapScanDesc scan, { HeapTuple tuple = &(scan->rs_ctup); Page page; - int lineindex; - int linesleft; + uint32 lineindex; + uint32 linesleft; if (likely(scan->rs_inited)) { @@ -989,6 +991,7 @@ continue_page: ItemId lpp; OffsetNumber lineoff; + Assert(lineindex <= scan->rs_ntuples); lineoff = scan->rs_vistuples[lineindex]; lpp = PageGetItemId(page, lineoff); Assert(ItemIdIsNormal(lpp)); diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c index a8d95e0f1c1..d0e5922eed7 100644 --- a/src/backend/access/heap/heapam_handler.c +++ b/src/backend/access/heap/heapam_handler.c @@ -2303,7 +2303,7 @@ heapam_scan_bitmap_next_tuple(TableScanDesc scan, /* * Out of range? If so, nothing more to look at on this page */ - if (hscan->rs_cindex < 0 || hscan->rs_cindex >= hscan->rs_ntuples) + if (hscan->rs_cindex >= hscan->rs_ntuples) return false; targoffset = hscan->rs_vistuples[hscan->rs_cindex]; diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h index 96cf82f97b7..04afb1a6a66 100644 --- a/src/include/access/heapam.h +++ b/src/include/access/heapam.h @@ -103,8 +103,8 @@ typedef struct HeapScanDescData int rs_empty_tuples_pending; /* these fields only used in page-at-a-time mode and for bitmap scans */ - int rs_cindex; /* current tuple's index in vistuples */ - int rs_ntuples; /* number of visible tuples on page */ + uint32 rs_cindex; /* current tuple's index in vistuples */ + uint32 rs_ntuples; /* number of visible tuples on page */ OffsetNumber rs_vistuples[MaxHeapTuplesPerPage]; /* their offsets */ } HeapScanDescData; typedef struct HeapScanDescData *HeapScanDesc;