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Few simple performance fixes found with sysbench oltp.lua and Oprofile:

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- Avoid needless load/stores in my_hash_sort_simple due to possible aliasing
 - Avoid expensive Join_plan_state constructor in choose_subquery_plan when no subquery
 - Avoid calling update_virtual_fields for every row when no virtual fields.
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unknown
2012-03-21 09:55:48 +01:00
parent 9a04194428
commit 07de9ab7fc
6 changed files with 41 additions and 27 deletions
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13
strings/ctype-simple.c
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@ -306,19 +306,24 @@ void my_hash_sort_simple(CHARSET_INFO *cs,
{
register const uchar *sort_order=cs->sort_order;
const uchar *end;
ulong n1, n2;
/*
Remove end space. We have to do this to be able to compare
'A ' and 'A' as identical
*/
end= skip_trailing_space(key, len);
n1= *nr1;
n2= *nr2;
for (; key < (uchar*) end ; key++)
{
nr1[0]^=(ulong) ((((uint) nr1[0] & 63)+nr2[0]) *
((uint) sort_order[(uint) *key])) + (nr1[0] << 8);
nr2[0]+=3;
n1^=(ulong) ((((uint) n1 & 63)+n2) *
((uint) sort_order[(uint) *key])) + (n1 << 8);
n2+=3;
}
*nr1= n1;
*nr2= n2;
}