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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2002-08-06 02:36:35 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2002-08-06 02:36:35 +0000 |
| commit | 5df307c7782518c4a3c19ffd05c7cb591b97e23c (patch) | |
| tree | 0ff988dc5b7b115e9f6bbf29852dd4bad7fcaeea /src/backend/access/heap/hio.c | |
| parent | 35cd432b185938c33967c9fa48223ce33e1c66bd (diff) | |
| download | postgresql-5df307c7782518c4a3c19ffd05c7cb591b97e23c.tar.gz postgresql-5df307c7782518c4a3c19ffd05c7cb591b97e23c.zip | |
Restructure local-buffer handling per recent pghackers discussion.
The local buffer manager is no longer used for newly-created relations
(unless they are TEMP); a new non-TEMP relation goes through the shared
bufmgr and thus will participate normally in checkpoints. But TEMP relations
use the local buffer manager throughout their lifespan. Also, operations
in TEMP relations are not logged in WAL, thus improving performance.
Since it's no longer necessary to fsync relations as they move out of the
local buffers into shared buffers, quite a lot of smgr.c/md.c/fd.c code
is no longer needed and has been removed: there's no concept of a dirty
relation anymore in md.c/fd.c, and we never fsync anything but WAL.
Still TODO: improve local buffer management algorithms so that it would
be reasonable to increase NLocBuffer.
Diffstat (limited to 'src/backend/access/heap/hio.c')
| -rw-r--r-- | src/backend/access/heap/hio.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/backend/access/heap/hio.c b/src/backend/access/heap/hio.c index 602ad748d9b..67eb4ad7e24 100644 --- a/src/backend/access/heap/hio.c +++ b/src/backend/access/heap/hio.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Id: hio.c,v 1.45 2002/06/20 20:29:25 momjian Exp $ + * $Id: hio.c,v 1.46 2002/08/06 02:36:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -102,6 +102,7 @@ RelationGetBufferForTuple(Relation relation, Size len, Size pageFreeSpace; BlockNumber targetBlock, otherBlock; + bool needLock; len = MAXALIGN(len); /* be conservative */ @@ -231,9 +232,12 @@ RelationGetBufferForTuple(Relation relation, Size len, * * We have to use a lock to ensure no one else is extending the rel at * the same time, else we will both try to initialize the same new - * page. + * page. We can skip locking for new or temp relations, however, + * since no one else could be accessing them. */ - if (!relation->rd_myxactonly) + needLock = !(relation->rd_isnew || relation->rd_istemp); + + if (needLock) LockPage(relation, 0, ExclusiveLock); /* @@ -249,7 +253,7 @@ RelationGetBufferForTuple(Relation relation, Size len, * Release the file-extension lock; it's now OK for someone else to * extend the relation some more. */ - if (!relation->rd_myxactonly) + if (needLock) UnlockPage(relation, 0, ExclusiveLock); /* |