diff options
| author | Teodor Sigaev <teodor@sigaev.ru> | 2005-09-16 14:40:54 +0000 |
|---|---|---|
| committer | Teodor Sigaev <teodor@sigaev.ru> | 2005-09-16 14:40:54 +0000 |
| commit | f4516f87322b87ff40ce76cd51b71efe02ad1886 (patch) | |
| tree | 16b33d4d8084e3b53372aa8def0544b6f1aa3ce0 /src/backend/access/gist | |
| parent | 3f558e3daeec6e87b509d4c816480edf1931b609 (diff) | |
| download | postgresql-f4516f87322b87ff40ce76cd51b71efe02ad1886.tar.gz postgresql-f4516f87322b87ff40ce76cd51b71efe02ad1886.zip | |
Small fixes
Diffstat (limited to 'src/backend/access/gist')
| -rw-r--r-- | src/backend/access/gist/README | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/src/backend/access/gist/README b/src/backend/access/gist/README index b47c5d330aa..1d828b30ffe 100644 --- a/src/backend/access/gist/README +++ b/src/backend/access/gist/README @@ -1,4 +1,4 @@ -$PostgreSQL: pgsql/src/backend/access/gist/README,v 1.2 2005/09/15 17:44:27 neilc Exp $ +$PostgreSQL: pgsql/src/backend/access/gist/README,v 1.3 2005/09/16 14:40:54 teodor Exp $ This directory contains an implementation of GiST indexing for Postgres. @@ -21,7 +21,9 @@ The current implementation of GiST supports: * Concurrency * Recovery support via WAL logging -The support for concurrency implemented in PostgreSQL was developed based on the paper "Access Methods for Next-Generation Database Systems" by Marcel Kornaker: +The support for concurrency implemented in PostgreSQL was developed based on +the paper "Access Methods for Next-Generation Database Systems" by +Marcel Kornaker: http://www.sai.msu.su/~megera/postgres/gist/papers/concurrency/access-methods-for-next-generation.pdf.gz @@ -31,11 +33,11 @@ The original algorithms were modified in several ways: algorithm was considerably changed, because in PostgreSQL function search should return one tuple (next), not all tuples at once. Also, it should release page locks between calls. -* Since we added support for variable length keys, it's not possible to guarantee - enough free space for all keys on pages after splitting. User defined function - picksplit doesn't have information about size of tuples (each tuple may - contain several keys as in multicolumn index while picksplit could work with - only one key) and pages. +* Since we added support for variable length keys, it's not possible to + guarantee enough free space for all keys on pages after splitting. User + defined function picksplit doesn't have information about size of tuples + (each tuple may contain several keys as in multicolumn index while picksplit + could work with only one key) and pages. * We modified original INSERT algorithm for performance reason. In particular, it is now a single-pass algorithm. * Since the papers were theoretical, some details were omitted and we @@ -197,7 +199,7 @@ placetopage(page, keysarray) if ( no space left on page ) keysarray = pageSplit(page, [ extract_keys(page), keysarray]) last page in chain gets old NSN, - original and others - new NSN from current LSN + original and others - new NSN equals to LSN if ( page is root ) make new root with keysarray end |