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Diffstat (limited to 'doc/TODO')
| -rw-r--r-- | doc/TODO | 15 |
1 files changed, 9 insertions, 6 deletions
@@ -2,7 +2,7 @@ PostgreSQL TODO List ==================== Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) -Last updated: Thu Dec 1 17:30:23 EST 2005 +Last updated: Thu Dec 1 23:28:03 EST 2005 The most recent version of this document can be viewed at http://www.postgresql.org/docs/faqs.TODO.html. @@ -862,11 +862,14 @@ Cache Usage 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. 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. + 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. Frequently + accessed bitmaps would have to be stored in shared memory. One 8k + page of bitmaps could track 512MB of heap pages. * Consider automatic caching of queries at various levels: |