Bug #61060 Mixed direction indexes
Submitted: 4 May 2011 16:43 Modified: 4 May 2011 19:48
Reporter: Stephen Jackson Email Updates:
Status: Duplicate Impact on me:
None 
Category:MySQL Server Severity:S3 (Non-critical)
Version:All OS:Any
Assigned to: CPU Architecture:Any
Tags: INDEX

[4 May 2011 16:43] Stephen Jackson 
Description:
Mixed direction indexes do not work when specifying (a asc, b desc, c asc) for example. The documentation states that asc / desc is there for future implementations. When can we see this implemented? For large datasets which are queried often in the same way ex "order by a asc, b desc, c asc" this would be a major boost to mysql performance.

How to repeat:
create a test table with columns a,b,c.

create index test_index on test_table (a asc, b desc, c desc);

fill with some data.

do a query which orders by a asc, b desc, c desc

direction is ignored, query result in filesort.

Suggested fix:
Please implement mixed direction indexes.
[4 May 2011 19:48] MySQL Verification Team 
duplicate of bug #13375