@@ -532,24 +532,29 @@ ptrack_get_pagemapset(PG_FUNCTION_ARGS)
532532
533533hash = BID_HASH_FUNC (ctx -> bid );
534534slot1 = hash %PtrackContentNblocks ;
535- slot2 = ((hash <<32 ) | (hash >>32 )) %PtrackContentNblocks ;
536535
537536update_lsn1 = pg_atomic_read_u64 (& ptrack_map -> entries [slot1 ]);
538- update_lsn2 = pg_atomic_read_u64 (& ptrack_map -> entries [slot2 ]);
539537
540538if (update_lsn1 != InvalidXLogRecPtr )
541539elog (DEBUG3 ,"ptrack: update_lsn1 %X/%X of blckno %u of file %s" ,
542540 (uint32 ) (update_lsn1 >>32 ), (uint32 )update_lsn1 ,
543541ctx -> bid .blocknum ,ctx -> relpath );
544542
545- if (update_lsn2 != InvalidXLogRecPtr )
546- elog (DEBUG3 ,"ptrack: update_lsn2 %X/%X of blckno %u of file %s" ,
547- (uint32 ) (update_lsn1 >>32 ), (uint32 )update_lsn2 ,
548- ctx -> bid .blocknum ,ctx -> relpath );
543+ /* Only probe the second slot if the first one is marked */
544+ if (update_lsn1 >=ctx -> lsn )
545+ {
546+ slot2 = ((hash <<32 ) | (hash >>32 )) %PtrackContentNblocks ;
547+ update_lsn2 = pg_atomic_read_u64 (& ptrack_map -> entries [slot2 ]);
549548
550- /* Block has been changed since specified LSN. Mark it in the bitmap */
551- if (update_lsn1 >=ctx -> lsn && update_lsn2 >=ctx -> lsn )
552- datapagemap_add (& pagemap ,ctx -> bid .blocknum % ((BlockNumber )RELSEG_SIZE ));
549+ if (update_lsn2 != InvalidXLogRecPtr )
550+ elog (DEBUG3 ,"ptrack: update_lsn2 %X/%X of blckno %u of file %s" ,
551+ (uint32 ) (update_lsn1 >>32 ), (uint32 )update_lsn2 ,
552+ ctx -> bid .blocknum ,ctx -> relpath );
553+
554+ /* Block has been changed since specified LSN. Mark it in the bitmap */
555+ if (update_lsn2 >=ctx -> lsn )
556+ datapagemap_add (& pagemap ,ctx -> bid .blocknum % ((BlockNumber )RELSEG_SIZE ));
557+ }
553558
554559ctx -> bid .blocknum += 1 ;
555560}