I just did a major refactor and shard on our PG schema and the performance improvement was dramatic ... a big plus for PG, if it is e.g. time-series data is to shard by time and make the tables write-once. The same applies to any record id that doesn't get re-used. PG doesn't do in-place record updates, so tables with lots of row changes can get order-fragmented.
If not, also check out the "cluster table on index" command.
Cheers
Dave
On Wed, May 5, 2010 at 3:25 PM, Richard Yen <dba@xxxxxxxxxxx> wrote:
Hello,
I'm about to embark on a partitioning project to improve read performance on some of our tables:
db=# select relname,n_live_tup,pg_size_pretty(pg_relation_size(relid)) from pg_stat_all_tables where schemaname = 'public' order by n_live_tup desc limit 10;
relname | n_live_tup | pg_size_pretty
-------------------------------------+------------+----------------
objects | 125255895 | 11 GB
papers | 124213085 | 14 GB
stats | 124202261 | 9106 MB
exclusions | 53090902 | 3050 MB
marks | 42467477 | 4829 MB
student_class | 31491181 | 1814 MB
users | 19906017 | 3722 MB
view_stats | 12031074 | 599 MB
highlights | 10884380 | 629 MB
Problem is, I have foreign keys that link almost all of our tables together (as a business requirement/IT policy). However, I know (er, I have a gut feeling) that many people out there have successfully deployed table partitioning, so I'm hoping to solicit some advice with respect to this. I've looked at documentation, tried creating a prototype, etc...looks like foreign keys have to go. But do they? What have other people out there done to get their tables partitioned?
Any input would be much appreciated.
Thanks!
--Richard
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