diff options
Diffstat (limited to 'src/backend/storage/smgr/md.c')
| -rw-r--r-- | src/backend/storage/smgr/md.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c index b9c1273702f..643c75e538b 100644 --- a/src/backend/storage/smgr/md.c +++ b/src/backend/storage/smgr/md.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.143 2009/01/01 17:23:48 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.144 2009/01/12 05:10:44 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -551,6 +551,26 @@ mdclose(SMgrRelation reln, ForkNumber forknum) } /* + * mdprefetch() -- Initiate asynchronous read of the specified block of a relation + */ +void +mdprefetch(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum) +{ +#ifdef USE_PREFETCH + off_t seekpos; + MdfdVec *v; + + v = _mdfd_getseg(reln, forknum, blocknum, false, EXTENSION_FAIL); + + seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)); + Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE); + + (void) FilePrefetch(v->mdfd_vfd, seekpos, BLCKSZ); +#endif /* USE_PREFETCH */ +} + + +/* * mdread() -- Read the specified block from a relation. */ void |