"Because it's policy" is rarely a good design decision :-) Lose the FK
constraints, and make up for them with integrity checking queries.
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.
On Wed, May 5, 2010 at 3:25 PM, Richard Yen <dba(at)richyen(dot)com> wrote:
> 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.
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