Re: Including Snapshot Info with Indexes
От | Csaba Nagy |
---|---|
Тема | Re: Including Snapshot Info with Indexes |
Дата | |
Msg-id | 1191834497.16320.18.camel@PCD12478 обсуждение исходный текст |
Ответ на | Re: Including Snapshot Info with Indexes ("Heikki Linnakangas" <heikki@enterprisedb.com>) |
Ответы |
Re: Including Snapshot Info with Indexes
|
Список | pgsql-hackers |
On Mon, 2007-10-08 at 09:40 +0100, Heikki Linnakangas wrote: > This idea has been discussed to death many times before. Please search > the archives. Somewhat related to the "visibility in index" thing: would it be possible to have a kind of index-table ? We do have here some tables which have 2-4 fields, and the combination of them forms the primary key of the table. There are usually no other indexes on the table, and the net result is that the PK index duplicates the heap. So it would be cool if the index would be THE heap somehow... The most prominent example of this in our DBs is this table: db> \d table_a Table "public.table_a" Column | Type | Modifiers -----------+--------+----------- id_1 | bigint | not null id_2 | bigint | not null Indexes: "pk_table_a" PRIMARY KEY, btree (id_1, id_2) db> select reltuples::bigint, relpages from pg_class where relname='table_a';reltuples | relpages -----------+----------445286464 | 710090 (1 row) db> select reltuples::bigint, relpages from pg_class where relname='pk_table_a';reltuples | relpages -----------+----------445291072 | 599848 (1 row) This postgres install is compiled with 32K page size (for the ones who wonder about the page counts). In any case, it is clear that the index basically duplicates the heap... Cheers, Csaba.
В списке pgsql-hackers по дате отправления: