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Current maintainer:Bruce Momjian (pgman@candle.pha.pa.us)

Last updated:Wed Nov3 22:57:53 EST 2004

Last updated:Thu Nov4 11:19:28 EST 2004

The most recent version of this document can be viewed at the PostgreSQL web

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order. Another method would be to sort heap ctids matching the index

before accessing the heap rows.

* Allow the creation of bitmap indexes which can be quickly combined

with other bitmap indexes

* Allow non-bitmap indexes to be combined by creating bitmaps in memory

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.

combined. They can index by tid or can be lossy requiring a scan of the

heap page to find matching rows.

* Allow non-bitmap indexes to be combined

* Allow the creation of on-disk bitmap indexes which can be quickly

combined with other bitmap indexes

Do lookups on non-bitmap indexes and create bitmaps in memory that can be

combined with other indexes.

Such indexes could be more compact if there are few unique value.

* Allow use of indexes to search for NULLs