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commit    810aaf7f2706efb7284deea918454cc06c1b747e
Author:   David Rowley <drowley@postgresql.org>
Date:     Tue Oct 21 07:48:06 2025 +0000
First released in: 13.23, 14.20, 15.15, 16.11, 17.7, 18.1

    Fix BRIN 32-bit counter wrap issue with huge tables
    
    A BlockNumber (32-bit) might not be large enough to add bo_pagesPerRange
    to when the table contains close to 2^32 pages.  At worst, this could
    result in a cancellable infinite loop during the BRIN index scan with
    power-of-2 pagesPerRange, and slow (inefficient) BRIN index scans and
    scanning of unneeded heap blocks for non power-of-2 pagesPerRange.
    
    Backpatch to all supported versions.
    
    Author: sunil s <sunilfeb26@gmail.com>
    Reviewed-by: David Rowley <dgrowleyml@gmail.com>
    Reviewed-by: Michael Paquier <michael@paquier.xyz>
    Discussion: https://postgr.es/m/CAOG6S4-tGksTQhVzJM19NzLYAHusXsK2HmADPZzGQcfZABsvpA@mail.gmail.com
    Backpatch-through: 13


 src/backend/access/brin/brin.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index d3b5f349a24..9f8838ffa03 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -360,7 +360,6 @@ bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 	Relation	heapRel;
 	BrinOpaque *opaque;
 	BlockNumber nblocks;
-	BlockNumber heapBlk;
 	int64		totalpages = 0;
 	FmgrInfo   *consistentFn;
 	MemoryContext oldcxt;
@@ -521,9 +520,10 @@ bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 	/*
 	 * Now scan the revmap.  We start by querying for heap page 0,
 	 * incrementing by the number of pages per range; this gives us a full
-	 * view of the table.
+	 * view of the table.  We make use of uint64 for heapBlk as a BlockNumber
+	 * could wrap for tables with close to 2^32 pages.
 	 */
-	for (heapBlk = 0; heapBlk < nblocks; heapBlk += opaque->bo_pagesPerRange)
+	for (uint64 heapBlk = 0; heapBlk < nblocks; heapBlk += opaque->bo_pagesPerRange)
 	{
 		bool		addrange;
 		bool		gottuple = false;
@@ -535,7 +535,7 @@ bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 
 		MemoryContextResetAndDeleteChildren(perRangeCxt);
 
-		tup = brinGetTupleForHeapBlock(opaque->bo_rmAccess, heapBlk, &buf,
+		tup = brinGetTupleForHeapBlock(opaque->bo_rmAccess, (BlockNumber ) heapBlk, &buf,
 									   &off, &size, BUFFER_LOCK_SHARE,
 									   scan->xs_snapshot);
 		if (tup)
@@ -711,7 +711,7 @@ bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 		/* add the pages in the range to the output bitmap, if needed */
 		if (addrange)
 		{
-			BlockNumber pageno;
+			uint64 pageno;
 
 			for (pageno = heapBlk;
 				 pageno <= Min(nblocks, heapBlk + opaque->bo_pagesPerRange) - 1;


[parent: 4c3795c582db]