Re: postgresql13-llvm jit-13.5-1PGDG.rhel8.x86_64

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 11/15/21 00:04, Pavel Stehule wrote:

Hi


There is a CentOS8-stream version which solves the problem but I cannot
use that in the office. I will probably have to wait for another month
before OL8 has everything that I need in its repositories. Now, the
question is what kind of an impact will running without llvm-jit have?
According to the links below, llvm-jit effects are quite spectacular:

https://llvm.org/devmtg/2016-09/slides/Melnik-PostgreSQLLLVM.pdf

https://www.pgcon.org/2017/schedule/events/1092.en.html

When JIT was used on very large query with a lot of CASE expr, then JIT has a positive effect about 50%. On usual large queries, the effect of JIT was about 20%. Unfortunately, JIT is sensitive to estimation, and the JIT sometimes increases seconds to queries, although without JIT this query is executed in ms. When you use a query that can be well calculated in parallel, then positive effect of JIT is less.

Regards

Pavel

Thanks Pavel, you answered my question. I'll wait with the upgrade.

Regards

--

Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com

[Postgresql General]     [Postgresql PHP]     [PHP Users]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Yosemite]

  Powered by Linux