Rework handling of OOM when allocating record buffer in XLOG reader.

MasaoFujii · MasaoFujii · commit 9b8d4782ba0f · 2015-04-03T18:29:38.000+09:00
Commit 2c03216 changed allocate_recordbuf() so that it uses a palloc to allocate the read buffer and fails immediately when an out-of-memory error shows up, even though its callers still expect that NULL is returned in that case. This bug is fixed making allocate_recordbuf() use a palloc_extended with MCXT_ALLOC_NO_OOM flag and return NULL in OOM case. Michael Paquier
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
@@ -146,7 +146,13 @@ allocate_recordbuf(XLogReaderState *state, uint32 reclength)
 
 	if (state->readRecordBuf)
 		pfree(state->readRecordBuf);
-	state->readRecordBuf = (char *) palloc(newSize);
+	state->readRecordBuf =
+		(char *) palloc_extended(newSize, MCXT_ALLOC_NO_OOM);
+	if (state->readRecordBuf == NULL)
+	{
+		state->readRecordBufSize = 0;
+		return false;
+	}
 	state->readRecordBufSize = newSize;
 	return true;
 }
