Fix memory leak in xlogreader facility.

hlinnaka · hlinnaka · commit 03a0a3532b47 · 2015-07-27T18:30:27.000+03:00
XLogReaderFree failed to free the per-block data buffers, when they
happened to not be used by the latest read WAL record.

Michael Paquier. Backpatch to 9.5, where the per-block buffers were added.
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
@@ -126,11 +126,8 @@ XLogReaderFree(XLogReaderState *state)
 
 	for (block_id = 0; block_id <= state->max_block_id; block_id++)
 	{
-		if (state->blocks[block_id].in_use)
-		{
-			if (state->blocks[block_id].data)
-				pfree(state->blocks[block_id].data);
-		}
+		if (state->blocks[block_id].data)
+			pfree(state->blocks[block_id].data);
 	}
 	if (state->main_data)
 		pfree(state->main_data);

Original file line number	Diff line number	Diff line change
`@@ -126,11 +126,8 @@ XLogReaderFree(XLogReaderState *state)`
`126`	`126`
`127`	`127`	`for (block_id = 0; block_id <= state->max_block_id; block_id++)`
`128`	`128`	`{`
`129`		`- if (state->blocks[block_id].in_use)`
`130`		`- {`
`131`		`- if (state->blocks[block_id].data)`
`132`		`- pfree(state->blocks[block_id].data);`
`133`		`- }`
	`129`	`+ if (state->blocks[block_id].data)`
	`130`	`+ pfree(state->blocks[block_id].data);`
`134`	`131`	`}`
`135`	`132`	`if (state->main_data)`
`136`	`133`	`pfree(state->main_data);`