diff options
| author | Bruce Momjian | 2004-11-04 03:57:58 +0000 |
|---|---|---|
| committer | Bruce Momjian | 2004-11-04 03:57:58 +0000 |
| commit | 4fbdfbffc64d3d5b64e6758d4795a8316636f1a1 (patch) | |
| tree | 5a9a09950be9522032b858de7eb5a5466014f8d6 | |
| parent | c21214f1c0e4fb206d7286c6f0bf95fe94627527 (diff) | |
Update:
< * Use bitmaps to combine existing indexes [performance]
> * Allow the creation of bitmap indexes which can be quickly combined
> with other bitmap indexes
255,257c256,266
< Bitmap indexes allow single indexed columns to be combined to
< dynamically create a composite index to match a specific query. Each
< index is a bitmap, and the bitmaps are AND'ed or OR'ed to be combined.
> Bitmap indexes index single columns that can be combined with other bitmap
> indexes to dynamically create a composite index to match a specific query.
> Each index is a bitmap, and the bitmaps are bitwise AND'ed or OR'ed to be
> combined. Such indexes could be more compact if there are few unique
> value. Also, perhaps they can be lossy requiring a scan of the heap page
> to find matching rows.
>
> * Allow non-bitmap indexes to be combined
>
> Do lookups on non-bitmap indexes and create bitmaps in memory that can be
> combined with other indexes.
| -rw-r--r-- | doc/TODO | 12 |
1 files changed, 8 insertions, 4 deletions
@@ -5,7 +5,7 @@ TODO list for PostgreSQL Bracketed items "[]" have more detail. Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) -Last updated: Wed Nov 3 17:20:38 EST 2004 +Last updated: Wed Nov 3 22:57:53 EST 2004 The most recent version of this document can be viewed at the PostgreSQL web site, http://www.PostgreSQL.org. @@ -253,14 +253,18 @@ Indexes * Allow the creation of bitmap indexes which can be quickly combined with other bitmap indexes - Bitmap indexes index single columns and can be combined with other bitmap + Bitmap indexes index single columns that can be combined with other bitmap indexes to dynamically create a composite index to match a specific query. Each index is a bitmap, and the bitmaps are bitwise AND'ed or OR'ed to be - combined. + combined. Such indexes could be more compact if there are few unique + value. Also, perhaps they can be lossy requiring a scan of the heap page + to find matching rows. * Allow non-bitmap indexes to be combined - Do loUse bitmaps to combine non-bitmap indexes + Do lookups on non-bitmap indexes and create bitmaps in memory that can be + combined with other indexes. + * Allow use of indexes to search for NULLs One solution is to create a partial index on an IS NULL expression. |