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MDEV-5846 MySQL Bug #18144 - Cost with FORCE/USE index seems incorrect in some cases.

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This commit is contained in:
Sergei Golubchik
2014-03-20 23:27:08 +01:00
parent dee0fd4233
commit 3bb249612f
4 changed files with 69 additions and 2 deletions
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12
sql/handler.h
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@ -2721,6 +2721,18 @@ public:
}
virtual double scan_time()
{ return ulonglong2double(stats.data_file_length) / IO_SIZE + 2; }
/**
The cost of reading a set of ranges from the table using an index
to access it.
@param index The index number.
@param ranges The number of ranges to be read.
@param rows Total number of rows to be read.
This method can be used to calculate the total cost of scanning a table
using an index by calling it using read_time(index, 1, table_size).
*/
virtual double read_time(uint index, uint ranges, ha_rows rows)
{ return rows2double(ranges+rows); }