PostgreSQL 11 preview - JIT接口放开
背景
LLVM对大量数据运算(比如说where条件中过滤大量的数据，聚合计算大量的数据等)的效率提升非常的明显。
原理参考
《分析加速引擎黑科技 - LLVM、列存、多核并行、算子复用 大联姻 - 一起来开启PostgreSQL的百宝箱》
PostgreSQL 11的JIT接口正在进行打磨，完善。借助LLVM，更多的并行计算的完善，PostgreSQL 11又会有一个质的飞越。解决企业OLTP和OLAP混合使用的需求。做到一个产品，解决小事务和大数据量密集计算的混合需求。
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=2a0faed9d7028e3830998bd6ca900be651274e27
Add expression compilation support to LLVM JIT provider.
author Andres Freund <andres@anarazel.de>
Tue, 20 Mar 2018 17:20:46 +0800 (02:20 -0700)
committer Andres Freund <andres@anarazel.de>
Fri, 23 Mar 2018 05:45:59 +0800 (14:45 -0700)
commit 2a0faed9d7028e3830998bd6ca900be651274e27
tree 0ab54ad8ac5c5d97d7a4dcee4c2d99c7959af2f6 tree | snapshot
parent 7ced1d1247286399df53823eb76cacaf6d7fdb22 commit | diff
Add expression compilation support to LLVM JIT provider.
In addition to the interpretation of expressions (which back
evaluation of WHERE clauses, target list projection, aggregates
transition values etc) support compiling expressions to native code,
using the infrastructure added in earlier commits.
To avoid duplicating a lot of code, only support emitting code for
cases that are likely to be performance critical. For expression steps
that aren't deemed that, use the existing interpreter.
The generated code isn't great - some architectural changes are
required to address that. But this already yields a significant
speedup for some analytics queries, particularly with WHERE clauses
filtering a lot, or computing multiple aggregates.
Author: Andres Freund
Tested-By: Thomas Munro
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
Disable JITing for VALUES() nodes.
VALUES() nodes are only ever executed once. This is primarily helpful
for debugging, when forcing JITing even for cheap queries.
Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
参考
《分析加速引擎黑科技 - LLVM、列存、多核并行、算子复用 大联姻 - 一起来开启PostgreSQL的百宝箱》
《PostgreSQL VOPS 向量计算 + DBLINK异步并行 - 单实例 10亿 聚合计算跑进2秒》