MySQL Community Server 5.5.6-rc 放出

〇〇

mysql> create table t5_3_1 as
    -> select ID1,
    -> sum(case when ID1<>0 then cnt end) c1,
    -> sum(case when ha3=1   then cnt end) c2,
    -> sum(case when ha3=2   then cnt end) c4,
    -> sum(case when ha3=3   then cnt end) c6,
    -> sum(case when ha3=4   then cnt end) c8
    -> from (
    -> select substr(ID,1,6) ID1,count(*)cnt,ha3
    -> from hu
    -> group by ID1,ha3
    -> )a
    -> group by ID1
    -> order by ID1 ;
Query OK, 25 rows affected (9.49 sec)
Records: 25  Duplicates: 0  Warnings: 0

jinguanding

原帖由 〇〇 于 2010-9-21 10:12 发表
汇总性能也不错，但不知怎么用上并行
mysql> create table t5_3_0 as
    -> select ID,
    -> sum(case when ID0 then cnt end) c1,
    -> sum(case when ha3=1   then cnt end) c2,
    -> sum(case when ha3=2   then cnt end) c4,
    -> sum(case when ha3=3   then cnt end) c6,
    -> sum(case when ha3=4   then cnt end) c8
    -> from (
    -> select substr(ID,1,2) ID,count(*)cnt,ha3
    -> from hu
    -> group by substr(ID,1,2),ha3
    -> )a
    -> group by ID
    -> order by ID ;
Query OK, 1 row affected (9.14 sec)
Records: 1  Duplicates: 0  Warnings: 0

加强了对SMP架构的支持，以及其写I/O改进方法，所以导入也会快很多....要是InnoDB引擎哦...

jinguanding

另外看过其RC版本的BUG LIST，看来到GA版本出来还有不少差距，因为BUG不少.....

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关于多核的说法
http://dev.mysql.com/doc/refman/5.5/en/smp-improvements.html

1.5.1. Scalability Improvements
MySQL 5.5 modifications improve performance on SMP systems to increase scalability on multi-core systems. The changes affect InnoDB locking and memory management.
MySQL 5.5 incorporates changes in InnoDB that improve the performance of RW-locks by using atomic CPU instructions (on platforms where they are available), rather than less scalable mutexes. It is also possible for InnoDB memory allocation to be disabled and replaced by the normal malloc library, or by a different library that implements malloc such as tcmalloc on Linux or mtalloc on Solaris.
The reimplementation of RW-locks requires atomic instructions. A status variable, Innodb_have_atomic_builtins, shows whether the server was built with atomic instructions

ruochen-pb

我安装过5.5.4-M3版本，bug确实不少

5.5版本是原来的6.0版本来的，吸收了很多开源的patch，光这些patch的整合和优化又得一段时间了，再加上给复制增加的复杂度，应该还得不短的时间用于生产了

另外最近的L2 cache也很热，percona已经在5.1.49已经增加了这个功能，不知道最后mysql会不会增加进去

感觉percona的版本很有诱惑力

ruochen-pb

原帖由 〇〇 于 2010-9-21 13:05 发表
关于多核的说法
http://dev.mysql.com/doc/refman/5.5/en/smp-improvements.html

1.5.1. Scalability Improvements
MySQL 5.5 modifications improve performance on SMP systems to increase scalability on multi-core systems. The changes affect InnoDB locking and memory management.
MySQL 5.5 incorporates changes in InnoDB that improve the performance of RW-locks by using atomic CPU instructions (on platforms where they are available), rather than less scalable mutexes. It is also possible for InnoDB memory allocation to be disabled and replaced by the normal malloc library, or by a different library that implements malloc such as tcmalloc on Linux or mtalloc on Solaris.
The reimplementation of RW-locks requires atomic instructions. A status variable, Innodb_have_atomic_builtins, shows whether the server was built with atomic instructions

smp的patch好像是google贡献的，之前看有测试16 core的cpu

ucgary

希望明年3月份能够出来.