postgres.git / summary / log / commit / refs

commit    9ae7b5d1f3ad2dc31ba7552a19d2efb24e7dbc0e
Author:   Tomas Vondra <tomas.vondra@postgresql.org>
Date:     Sun Jul 02 16:54:09 2023 +0000
First released in: 17.0, 13.12, 14.9, 15.4, 16.0

    Fix memory leak in Incremental Sort rescans
    
    The Incremental Sort had a couple issues, resulting in leaking memory
    during rescans, possibly triggering OOM. The code had a couple of
    related flaws:
    
    1. During rescans, the sort states were reset but then also set to NULL
       (despite the comment saying otherwise). ExecIncrementalSort then
       sees NULL and initializes a new sort state, leaking the memory used
       by the old one.
    
    2. Initializing the sort state also automatically rebuilt the info about
       presorted keys, leaking the already initialized info. presorted_keys
       was also unnecessarily reset to NULL.
    
    Patch by James Coleman, based on patches by Laurenz Albe and Tom Lane.
    Backpatch to 13, where Incremental Sort was introduced.
    
    Author: James Coleman, Laurenz Albe, Tom Lane
    Reported-by: Laurenz Albe, Zu-Ming Jiang
    Backpatch-through: 13
    Discussion: https://postgr.es/m/b2bd02dff61af15e3526293e2771f874cf2a3be7.camel%40cybertec.at
    Discussion: https://postgr.es/m/db03c582-086d-e7cd-d4a1-3bc722f81765%40inf.ethz.ch


 src/backend/executor/nodeIncrementalSort.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/src/backend/executor/nodeIncrementalSort.c b/src/backend/executor/nodeIncrementalSort.c
index 34257ce34be..7683e3341cd 100644
--- a/src/backend/executor/nodeIncrementalSort.c
+++ b/src/backend/executor/nodeIncrementalSort.c
@@ -1140,7 +1140,6 @@ ExecReScanIncrementalSort(IncrementalSortState *node)
 	node->outerNodeDone = false;
 	node->n_fullsort_remaining = 0;
 	node->bound_Done = 0;
-	node->presorted_keys = NULL;
 
 	node->execution_status = INCSORT_LOADFULLSORT;
 
@@ -1153,15 +1152,9 @@ ExecReScanIncrementalSort(IncrementalSortState *node)
 	 * cause a leak.
 	 */
 	if (node->fullsort_state != NULL)
-	{
 		tuplesort_reset(node->fullsort_state);
-		node->fullsort_state = NULL;
-	}
 	if (node->prefixsort_state != NULL)
-	{
 		tuplesort_reset(node->prefixsort_state);
-		node->prefixsort_state = NULL;
-	}
 
 	/*
 	 * If chgParam of subnode is not null, then the plan will be re-scanned by


[parent: cb5fd121d539]