Re:R17 on spinning disk faster than PostgreSQL on SSD
by molecule on Monday August 15, 2011 @11:48PM
(#2889780)
In default configuration for mysql and postgresql daemons, these benchmarks don't do anything to make full use of the hardware cited.
Here are guides for the respective db configs.
http://www.revsys.com/writings/postgresql-performance.html
http://www.mysqlperformanceblog.com/2006/09/29/what-to-tune-...
Re:R17 on spinning disk faster than PostgreSQL on SSD
by jpitz on Monday August 15, 2011 @11:56PM
(#2889804)
The effective_cache_size and shared_buffers settings from the revsys link are good, but thats generally older guidance ( max_fsm_pages is gone now )
If r17 doesn't use fsync.... Well. Perhaps you could show a postgres benchmark with that off. That's "Eat my data" mode. I don't recommend that mode, but it is faster, and might be more apples-to-apples.
MAINTENANCE_WORK_MEM and WORK_MEM could also help. Maybe. Thats a big dataset.
On SSD, random_page_cost may need tuned closer to sequential_page_cost.
[re reasonableness PostgreSQL being 20-40x slower] Yes, but only at some things. In the first bakeoff (http://www.rseventeen.com/blog/bakeoff_part_1_mysql_postgres...) PostgreSQL was clearly "better" than MySQL. And r17 can't do transactions and is useless for anything "on line", which is where PostgreSQL really shines. (As commented below) next up I'll be baking off against Hadoop, which is a more apples<->apples comparison.
[re misconfiguration] is there a specific configuration that you would prefer that I use? I'm also happy to show the EXPLAIN output if that would help.