Josh Harrison escribió: > Another quick question...When you issue a query like this > select * from dummy limit 10 > What 10 rows are fetched? like first 10 or last 10 or the first 10 from > first block or.... ?
Any 10. (First 10 in the physical table _if_ a seqscan is used). > And this query always returns the same 10 rows (when there are no > updates/deletes) Yes, assuming there is no VACUUM or CLUSTER either. And no inserts either if there is free space on the first pages. You really shouldn't trust it. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
