diff options
Diffstat (limited to 'src/backend/access/transam/xlogreader.c')
| -rw-r--r-- | src/backend/access/transam/xlogreader.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 0781a7b9de9..03971485726 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -1277,7 +1277,22 @@ DecodeXLogRecord(XLogReaderState *state, XLogRecord *record, char **errormsg) { if (state->main_data) pfree(state->main_data); - state->main_data_bufsz = state->main_data_len; + + /* + * main_data_bufsz must be MAXALIGN'ed. In many xlog record + * types, we omit trailing struct padding on-disk to save a few + * bytes; but compilers may generate accesses to the xlog struct + * that assume that padding bytes are present. If the palloc + * request is not large enough to include such padding bytes then + * we'll get valgrind complaints due to otherwise-harmless fetches + * of the padding bytes. + * + * In addition, force the initial request to be reasonably large + * so that we don't waste time with lots of trips through this + * stanza. BLCKSZ / 2 seems like a good compromise choice. + */ + state->main_data_bufsz = MAXALIGN(Max(state->main_data_len, + BLCKSZ / 2)); state->main_data = palloc(state->main_data_bufsz); } memcpy(state->main_data, ptr, state->main_data_len); |