From: Bruce Momjian Date: Thu, 1 Dec 2005 22:30:43 +0000 (+0000) Subject: Add all heap page rows visible bitmap idea: X-Git-Tag: REL9_0_0~8812 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=113ece8f3d704cdcf20f2865d1ea8964159ee476;p=pg-rex%2Fsyncrep.git Add all heap page rows visible bitmap idea: < the heap. One way to allow this is to set a bit to index tuples > the heap. One way to allow this is to set a bit on index tuples < be cleared when a heap tuple is expired. < > be cleared when a heap tuple is expired. Another idea is to maintain > a bitmap of heap pages where all rows are visible to all backends, > and allow index lookups to reference that bitmap to avoid heap > lookups, perhaps the same bitmap we might add someday to determine > which heap pages need vacuuming. --- diff --git a/doc/TODO b/doc/TODO index 22c6e3c461..c3bf43a5f8 100644 --- a/doc/TODO +++ b/doc/TODO @@ -2,7 +2,7 @@ PostgreSQL TODO List ==================== Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) -Last updated: Thu Dec 1 17:12:27 EST 2005 +Last updated: Thu Dec 1 17:30:23 EST 2005 The most recent version of this document can be viewed at http://www.postgresql.org/docs/faqs.TODO.html. @@ -859,11 +859,14 @@ Cache Usage Currently indexes do not have enough tuple visibility information to allow data to be pulled from the index without also accessing - the heap. One way to allow this is to set a bit to index tuples + the heap. One way to allow this is to set a bit on index tuples to indicate if a tuple is currently visible to all transactions when the first valid heap lookup happens. This bit would have to - be cleared when a heap tuple is expired. - + be cleared when a heap tuple is expired. Another idea is to maintain + a bitmap of heap pages where all rows are visible to all backends, + and allow index lookups to reference that bitmap to avoid heap + lookups, perhaps the same bitmap we might add someday to determine + which heap pages need vacuuming. * Consider automatic caching of queries at various levels: diff --git a/doc/src/FAQ/TODO.html b/doc/src/FAQ/TODO.html index 7bb7cd2842..7e4961eaa7 100644 --- a/doc/src/FAQ/TODO.html +++ b/doc/src/FAQ/TODO.html @@ -8,7 +8,7 @@

PostgreSQL TODO List

Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
-Last updated: Thu Dec 1 17:12:27 EST 2005 +Last updated: Thu Dec 1 17:30:23 EST 2005

The most recent version of this document can be viewed at
http://www.postgresql.org/docs/faqs.TODO.html. @@ -778,10 +778,14 @@ first.

Allow data to be pulled directly from indexes

Currently indexes do not have enough tuple visibility information to allow data to be pulled from the index without also accessing - the heap. One way to allow this is to set a bit to index tuples + the heap. One way to allow this is to set a bit on index tuples to indicate if a tuple is currently visible to all transactions when the first valid heap lookup happens. This bit would have to - be cleared when a heap tuple is expired. + be cleared when a heap tuple is expired. Another idea is to maintain + a bitmap of heap pages where all rows are visible to all backends, + and allow index lookups to reference that bitmap to avoid heap + lookups, perhaps the same bitmap we might add someday to determine + which heap pages need vacuuming.

Consider automatic caching of queries at various levels: