>>>>> "Hugo" == Hugo van der Sanden <hugo@stripped>
> writes:
Hugo> In <14272.14293.779425.635005@stripped>, Michael Widenius writes:
Hugo> Were that the case, I would have expected the same to happen in my
Hugo> test table with one record. However, it is not how I understand the SQL
Hugo> should work: regardless of implementation, I would expect the effect to
Hugo> be the same as if the where clause were first applied to find the set
Hugo> of matching records, and then the update clause applied (once!) to each
Hugo> member of the matching set.
Hugo> I suspect the fact that I am updating one field of a multi-field key is
Hugo> part of the reason for the problem.
Monty> Yes, this explain this case (This is fixed in 3.23.2)
Hugo> I've finally managed to get 3.23.2 installed here, and confirmed that
Hugo> the update works correctly with that version. Is there any prospect that
Hugo> the relevant patches will make it into a 3.22 release at some point in
Hugo> the near future? If not, I'd appreciate being pointed at the patches
Hugo> so I can attempt to retrofit them myself.
The problem is that there was a lot of things involved in this patch.
If we would put this in 3.22, then 3.22 have to be declared as 'alpha'
:(
You can find 'most things' that changed by doing:
diff -c mysql-3.22.25/sql/sql_update.c mysql-3.23.2/sql/sql_update.c
Some calls have got more parameters (like make_select), so to get this
to work in 3.22 you have to change the call back to the old format and
check that everything still works.
Hugo> As well as the reluctance to touch software marked 'alpha', the person
Hugo> who installed 3.23.2 on a test machine here also thought to check the
Hugo> benchmarks comparing 3.22.25 and 3.23.2, and while most operations are
Hugo> as fast or faster, there are a couple of worrying anomalies:
Hugo> Benchmark DBD suite: 2.2
Hugo> Running tests on: SunOS 5.7 sun4u
Hugo> alpha: Server version: MySQL 3.23.2 alpha
Hugo> stable: Server version: MySQL 3.22.25
Hugo> [...]
Hugo> alpha: All 8 test executed successfully
Hugo> stable: All 8 test executed successfully
Hugo> Tests with estimated time have a + at end of line
Hugo> Totals per operation:
Hugo> Operation seconds usr sys cpu tests
Hugo> [...]
Hugo> alpha: select_key 91476 123.29 53.27 0.00 200000 +
Hugo> stable: select_key 300 138.33 56.57 0.00 200000
Hugo> alpha: select_range 1945 38.02 30.16 0.00 25410 +
Hugo> stable: select_range 509 36.60 24.98 0.00 25420
Hugo> alpha: select_range_prefix 9551 13.44 7.20 0.00 25000 +
Hugo> stable: select_range_prefix 60 13.01 6.58 0.00 25010
Hugo> [...]
Hugo> alpha: TOTALS 111222 747.01 569.89 0.00 1511298 ++++
Hugo> stable: TOTALS 10908 781.22 489.97 0.00 1511318 +
I agree; There seems to be something wrong in the above. On the
other hand, I don't have this problems with my copy of 3.23.3.
I would suggest that you for a while remove the second part of the
index (message) until 3.23 reaches beta (hopefully within a couple of weeks).
Regards,
Monty
