David Shadovitz wrote, On 1/11/2004 7:10 PM:
I understand that COUNT queries are expensive. So I'm looking for advice on displaying paginated query results.
I display my query results like this:
Displaying 1 to 50 of 2905. 1-50 | 51-100 | 101-150 | etc.
I do this by executing two queries. One is of the form:
SELECT <select list> FROM <view/table list> WHERE <filter> LIMIT m OFFSET n
The other is identical except that I replace the select list with COUNT(*).
yes, you need 2 query. Or select it from one: select *, (select count(*) from table) as count from table...
pg will optimize this query, and do the count only once
And an unrelated question:
I'm running PG 7.2.2 and want to upgrade to 7.4.1. I've never upgraded PG before and I'm nervous. Can I simply run pg_dumpall, install 7.4.1, and then feed the dump into psql? I'm planning to use pg_dumpall rather than pg_dump because I want to preserve the users I've defined. My database is the only one on the system.
yes. But check tha faq and the manual for a better explain.
C.
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