0
votes
0answers
32 views

Speed up sorting in this query

I'm trying to optimize the following plan and noticed that PostgreSQL spends a lot of time (relatively speaking) on sorting before the merge joins. Is there a way (using indexes, cluster the table, ...
1
vote
0answers
88 views

Can't get rid of filesort on joined query sorting on second table

For some reason, this query: EXPLAIN SELECT * FROM biz as b INNER JOIN listings as l ON b.id = l.biz_id WHERE l.pub_id = 14 AND b.cat_id=310 ORDER BY l.level DESC, l.random DESC LIMIT 5; says it ...
2
votes
1answer
101 views

Are two indexes needed?

Our MySQL database will contain an encyclopedia. The encyclopedia will be shown in pages where every page contains entries starting from a letter. Which indexes should I use? Should I have two ...