[CONC-12] Support hash based aggregation method for GROUP BY Created: 2013-02-12 Updated: 2013-02-12 Resolved: 2013-02-12 |
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| Status: | Closed |
| Project: | MariaDB Connector/C |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Task | Priority: | Major |
| Reporter: | Mathew Johnston | Assignee: | Rasmus Johansson (Inactive) |
| Resolution: | Duplicate | Votes: | 0 |
| Labels: | None | ||
| Description |
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The current sort based GROUP BY implementation performs badly when source data is large and expected output is small. An alternative method, supported by Oracle, Postgres, SQL Server, etc. is to use hash aggregation, as described here: http://blogs.msdn.com/b/craigfr/archive/2006/09/20/hash-aggregate.aspx |
| Comments |
| Comment by Mathew Johnston [ 2013-02-12 ] |
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Shoot! Created against the wrong project - should be against the server. I don't seem to have any way of moving it. Apologies! |
| Comment by Mathew Johnston [ 2013-02-12 ] |
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Please close this one - I'll open another against the right project. Thanks! |
| Comment by Elena Stepanova [ 2013-02-12 ] |
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Duplicate of |