diff options
Diffstat (limited to 'src/backend/storage/smgr/smgr.c')
| -rw-r--r-- | src/backend/storage/smgr/smgr.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c index c9efd6341bc..aba6b4a7d8e 100644 --- a/src/backend/storage/smgr/smgr.c +++ b/src/backend/storage/smgr/smgr.c @@ -11,7 +11,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.77 2004/07/17 03:28:55 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.78 2004/08/15 23:44:46 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -621,14 +621,15 @@ smgrtruncate(SMgrRelation reln, BlockNumber nblocks, bool isTemp) * * Synchronously force all of the specified relation down to disk. * - * This is really only useful for non-WAL-logged index building: - * instead of incrementally WAL-logging the index build steps, - * we can just write completed index pages to disk with smgrwrite + * This is useful for building completely new relations (eg, new + * indexes). Instead of incrementally WAL-logging the index build + * steps, we can just write completed index pages to disk with smgrwrite * or smgrextend, and then fsync the completed index file before * committing the transaction. (This is sufficient for purposes of * crash recovery, since it effectively duplicates forcing a checkpoint - * for the completed index. But it is *not* workable if one wishes - * to use the WAL log for PITR or replication purposes.) + * for the completed index. But it is *not* sufficient if one wishes + * to use the WAL log for PITR or replication purposes: in that case + * we have to make WAL entries as well.) * * The preceding writes should specify isTemp = true to avoid * duplicative fsyncs. |