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This commit is contained in:
Sergei Petrunia
2014-09-25 14:29:14 +04:00
parent f5d845426e
commit e74bf07982
1 changed files with 9 additions and 6 deletions
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15
sql/sql_select.cc
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@@ -25224,15 +25224,18 @@ uint get_index_for_order(ORDER *order, TABLE *table, SQL_SELECT *select,
return MAX_KEY;
}
/*
Count how much times conditions are true for several first rows of the table
Count how many times the specified conditions are true for first rows_to_read
rows of the table.
@param thd thread handle
@param rows_to_read how much rows to check
@param table table which should be checked
@conds conds list of conditions and countars for them
@param thd Thread handle
@param rows_to_read How many rows to sample
@param table Table to use
@conds conds INOUT List of conditions and counters for them
@return number of really checked rows or 0 in case of error or empty table
@return Number of we've checked. It can be equal or less than rows_to_read.
0 is returned for error or when the table had no rows.
*/
ulong check_selectivity(THD *thd,