Guilhem Bichot wrote:
> Hello Roy,
>
> Roy Lyseng a écrit, Le 08.10.2009 14:34:
>> #At file:///home/rl136806/mysql/repo/mysql-6.0-codebase-bugfixing/
>> based on revid:guilhem@stripped
>>
>> 3645 Roy Lyseng 2009-10-08
>> Turn off optimizer-related switches in the 6.0 codebase.
>> -static const char *optimizer_switch_str="firstmatch=on,"
>> - "index_merge=on,"
>> - "index_merge_union=on,"
>> - "index_merge_sort_union=on,"
>> - "index_merge_intersection=on,"
>> - "loosescan=on,"
>> - "materialization=on,"
>> - "semijoin=on";
>> +static const char *optimizer_switch_str="firstmatch=off,"
>> + "index_merge=off,"
>> + "index_merge_union=off,"
>> + "index_merge_sort_union=off,"
>> + "index_merge_intersection=off,"
>> + "loosescan=off,"
>> + "materialization=off,"
>> + "semijoin=off";
>
> I think the goal of your task is to create a version as close to 5.1 as
> possible, then we later add back 6.0 optimizations when we have fixed
> bugs in them.
> If that's the goal, you cannot disable those optimizations which exist
> and are enabled by default in 5.1 (or you create a crippled version
> compared to 5.1): so I think all index_merge* flags should be left "on"
> as in 5.1.
> Just like you didn't set the default of engine condition pushdown to 0,
> because that would have disabled the 5.1 feature.
>
Hi Guilhem,
thanks for noticing, new patch committed.
Roy
