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Re: [Maria-developers] [Commits] Rev 3353: Performed re-factoring and re-structuring of the code for mwl#248: in file:///home/igor/maria/maria-5.5-mwl248-changes/
by Kristian Nielsen 03 Aug '12

03 Aug '12

Davi Arnaut <davi(a)twitter.com> writes: > On Thu, Jul 26, 2012 at 5:50 PM, Igor Babaev <igor(a)askmonty.org> wrote: >> + bzero(column_stats, sizeof(Column_statistics) * cnt); > > That's not allowed for non-POD types. Can you elaborate on exactly when bzero() (or memset() or similar) is allowed or not allowed? I searched in my C++ reference, and did not really find anything ... in fact I did not find anything that said memset(p, 0, sizeof(*p)) would _ever_ be allowed for a class. It is my understanding that even for C, memset(..., 0, ...) is only valid for integer types. Initialising with memset() floating-point and even pointers values is not well-defined! Or did I miss something? I think this is an important issue, as memset() of a C++ class is certainly wrong in many cases, and can lead to subtle and platform-dependent failures. So let's point out clearly the rules that apply, or define such rules if necessary: 1. Does the C and C++ standards define suitable rules? If so, we should use them. However, I suspect that memset() is invalid in standard C and C++ except for arrays of integers, which is excessively restrictive. 2. If C/C++ standard is not sufficient, we need to agree on a coding style (and stay within what works on all reasonable compilers/platforms). I would much prefer to find an existing standards rule or convention. But failing that I would suggest: - Only memset() and memcpy() structs. - Virtual functions are definitely out (in struct as well as members). - Constructors and destructors also must not be defined for such structs (or its members). - Derived classes also should never be memset()'ed. Class inheritance is likely to need extra info on some (present or future) platforms and compilers. - Do not have private: methods in such memset() structs. I do not think it matters to the code generated, but private: is meaningless if arbitrary code is manipulating the memory of the struct directly. Usually I would have no methods at all in structs that I plan to do memset() on. But I suppose we also need to look at what existing code does. Comments? - Kristian.

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Re: [Maria-developers] [Commits] Rev 3353: Performed re-factoring and re-structuring of the code for mwl#248: in file:///home/igor/maria/maria-5.5-mwl248-changes/
by Michael Widenius 31 Jul '12

31 Jul '12

Hi! >>>>> "Davi" == Davi Arnaut <davi(a)twitter.com> writes: Davi> On Mon, Jul 30, 2012 at 7:34 AM, Oleksandr Byelkin Davi> <sanja(a)montyprogram.com> wrote: >> 27.07.2012 20:57, Davi Arnaut пишет: >>> >>> Also, bzero is deprecated. >> AFAIK bzero is macro in our sources. Davi> It is a macro if not available. Which then becomes a problem because Davi> the bzero interface is not well defined (first argument begin char Davi> pointer versus void pointer). It should be pretty simple, let's not Davi> use deprecated and broken interfaces. Actually, in mariadb code (and original mysql code) we use bzero a lot and it's a stable, well tested, well known and well defined function. Better to always use the same code to reset memory than doing it many different ways. In MySQL code bzero() has been the offical and recommended way to reset memory. Regards, Monty

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Re: [Maria-developers] [Commits] Rev 3453: MWL#182: Explain running statements
by Sergei Golubchik 28 Jul '12

28 Jul '12

Hi, Sergey! On Jul 17, Sergey Petrunya wrote: > ------------------------------------------------------------ > revno: 3453 > revision-id: psergey(a)askmonty.org-20120717192703-bgt3xgkbs8qvz3tc > parent: psergey(a)askmonty.org-20120717175208-ruovz91shg0ph875 > committer: Sergey Petrunya <psergey(a)askmonty.org> > branch nick: 5.5-show-explain-r21 > timestamp: Tue 2012-07-17 23:27:03 +0400 > message: > MWL#182: Explain running statements > Address feedback from the second code review: > - Make SHOW EXPLAIN code convert the query string before pushing it as a warning text. > @@ -2135,8 +2135,35 @@ int fill_show_explain(THD *thd, TABLE_LI > } > else > { > + /* > + Push the query string as a warning. The query may be in a different > + charset than the charset that's used for error messages, so, convert it > + if needed. > + */ there's no test case for this. was it too difficult to create? Regards, Sergei

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[Maria-developers] question about MTR
by Rich Prohaska 25 Jul '12

25 Jul '12

Hello, It appears that MTR looks at a test and figures out the appropriate mysqld configuration needed to run the test. For example, if I have lines like "source include/have_XYZ.inc" in my test, MTR will run the test with the right storage engines loaded (and only those storage engines). Is this accurate? Thanks Rich Prohaska

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[Maria-developers] Please test: BUG#992942 & MDEV-325 patch
by Sergei Petrunia 19 Jul '12

19 Jul '12

Hi Elena, I've made a patch that fixes both BUG#992942 and MDEV-325. It is rather risky, as it touches the part of the code whose interaction with other parts of the code is not very well defined. This is why I request RQG testing. Could you please run some test that would use ORDER BY ... LIMIT, GROUP BY, subqueries, tables that may or may not be read with range/index_merge access, index condition pushdown, etc? (Yes, you may really need all of the above to trigger the problem. Check out analysis comments in the bug). The code is at: bzr+ssh://bazaar.launchpad.net/~maria-captains/maria/5.5-show-explain-test1 it is based on 5.5-show-explain, so SHOW EXPLAIN part can be tested, too. BR Sergei -- Sergei Petrunia, Software Developer Monty Program AB, http://askmonty.org Blog: http://s.petrunia.net/blog

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[Maria-developers] Statistics tables show up in userstat - intentional?
by Sergei Petrunia 12 Jul '12

12 Jul '12

Hello Igor, I've noticed that engine-independent statistics show up in userstats: +--------------+-------------+-----------+--------------+-------------------------+ | Table_schema | Table_name | Rows_read | Rows_changed | Rows_changed_x_#indexes | +--------------+-------------+-----------+--------------+-------------------------+ | bug929732 | c2 | 249 | 0 | 0 | | mysql | index_stat | 84 | 0 | 0 | | bug929732 | v | 276 | 0 | 0 | | mysql | column_stat | 44 | 0 | 0 | | bug929732 | c | 249 | 0 | 0 | | bug929732 | v3 | 837280 | 0 | 0 | | mysql | table_stat | 12 | 0 | 0 | | bug929732 | v4 | 3994 | 0 | 0 | | bug929732 | v2 | 53506 | 0 | 0 | +--------------+-------------+-----------+--------------+-------------------------+ Is this intentional? I've also started collecting some minimal docs at http://kb.askmonty.org/en/engine-independent-table-statistics/ BR Sergei -- Sergei Petrunia, Software Developer Monty Program AB, http://askmonty.org Blog: http://s.petrunia.net/blog

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[Maria-developers] 10.0-base tree created and is in buildbot
by Sergei Petrunia 11 Jul '12

11 Jul '12

Hello, As discussed before, I have created a 10.0-base tree at lp:~maria-captains/maria/10.0-base I've pushed there contents of 10.0-monty tree and have added the new tree to buildbot. lp:~maria-captains/maria/10.0 tree was deleted (it was created in error) BR Sergei -- Sergei Petrunia, Software Developer Monty Program AB, http://askmonty.org Blog: http://s.petrunia.net/blog

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Re: [Maria-developers] problem with savepoints in mariadb 5.5.25
by Rich Prohaska 11 Jul '12

11 Jul '12

Hello, Thanks. Per Elena's request, i created bug #1023404. Rich Prohaska On Wed, Jul 11, 2012 at 7:27 AM, Michael Widenius <michael.widenius(a)gmail.com> wrote: > > Hi! > >>>>>> "Rich" == Rich Prohaska <prohaska(a)tokutek.com> writes: > > Rich> Hello, > Rich> I posted our fix at lp:~prohaska7/maria/5.5-savepoint-offset-fix. > Rich> Does it make sense? > Rich> Thanks > Rich> Rich Prohaska > > Sergei, who wrote the handlerton interface, is just now on his way > home from his conference trip to China. He should be able to help you > with this issue as soon as he is back. > > Regards, > Monty

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[Maria-developers] problem with savepoints in mariadb 5.5.25
by Rich Prohaska 10 Jul '12

10 Jul '12

Hello, We observed a problem with savepoints in Mariadb 5.5.25. The problem at the SQL layer is that a "rollback to savepoint" statement would get an error after the savepoint was created. The problem was caused by the savepoint name in the savepoint stack getting overwritten by the handlerton savepoint_set method. Here is what we think is going on: 1. space is reserved in the savepoint memory for each handlerton in the ha_initialize_handlerton function. 2. then space is reserved for the SAVEPOINT object in ha_init. (Yes, ha_init gets called AFTER the ha_initialize_handlerton calls. 3. ha_savepoint computes the address of the handlerton's object as (uchar*)(sv+1) + ht->savepoint_offset. this assumes that the SAVEPOINT object is laid out first, followed by the handlerton's space. unfortunately, step (1) occurs before step (2) so this is not the case. Here is a possible fix: Move the base initialization of the savepoint_alloc_size from ha_init to the global intiializer. With this change, the handlerton's offsets are computed AFTER the SAVEPOINT space is reserved. Is this correct? Thanks Rich Prohaska

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[Maria-developers] Please test: Rev 3458: MDEV-376: Wrong result (missing rows) with index_merge+index_merge_intersection, join
by Sergei Petrunia 04 Jul '12

04 Jul '12

Hi Elena, Could you please re-run the tests with this fix: ----- Forwarded message from Sergey Petrunya <psergey(a)askmonty.org> ----- From: Sergey Petrunya <psergey(a)askmonty.org> To: commits(a)mariadb.org X-Mailer: mail (GNU Mailutils 1.2) Date: Wed, 4 Jul 2012 13:34:48 +0300 (EEST) Subject: [Commits] Rev 3458: MDEV-376: Wrong result (missing rows) with index_merge+index_merge_intersection, join in file:///home/psergey/dev2/5.5-look6/ At file:///home/psergey/dev2/5.5-look6/ ------------------------------------------------------------ revno: 3458 revision-id: psergey(a)askmonty.org-20120704103445-ro4sk3cwbbzn3t4p parent: psergey(a)askmonty.org-20120623161254-ido3pf16l31psyyv committer: Sergey Petrunya <psergey(a)askmonty.org> branch nick: 5.5-look6 timestamp: Wed 2012-07-04 14:34:45 +0400 message: MDEV-376: Wrong result (missing rows) with index_merge+index_merge_intersection, join - Let QUICK_RANGE_SELECT::init_ror_merged_scan() call quick->reset() only after we've set the column read bitmaps. === modified file 'mysql-test/r/index_merge_innodb.result' --- a/mysql-test/r/index_merge_innodb.result 2012-06-06 19:26:40 +0000 +++ b/mysql-test/r/index_merge_innodb.result 2012-07-04 10:34:45 +0000 @@ -777,4 +777,19 @@ commit; select * from t1 where t1.zone_id=830 AND modified=9; pk zone_id modified drop table t0, t1; +# +# MDEV-376: Wrong result (missing rows) with index_merge+index_merge_intersection, join +# +CREATE TABLE t1 ( +a INT, b CHAR(1), c CHAR(1), KEY(a), KEY(b) +) ENGINE=InnoDB; +INSERT INTO t1 VALUES (8,'v','v'),(8,'m','m'),(9,'d','d'); +SELECT ta.* FROM t1 AS ta, t1 AS tb +WHERE ( tb.b != ta.b OR tb.a = ta.a ) +AND ( tb.b = ta.c OR tb.b = ta.b ); +a b c +8 v v +8 m m +9 d d +DROP TABLE t1; set optimizer_switch= @optimizer_switch_save; === modified file 'mysql-test/t/index_merge_innodb.test' --- a/mysql-test/t/index_merge_innodb.test 2012-06-04 15:26:11 +0000 +++ b/mysql-test/t/index_merge_innodb.test 2012-07-04 10:34:45 +0000 @@ -156,6 +156,21 @@ select * from t1 where t1.zone_id=830 AN drop table t0, t1; +--echo # +--echo # MDEV-376: Wrong result (missing rows) with index_merge+index_merge_intersection, join +--echo # +CREATE TABLE t1 ( + a INT, b CHAR(1), c CHAR(1), KEY(a), KEY(b) +) ENGINE=InnoDB; + +INSERT INTO t1 VALUES (8,'v','v'),(8,'m','m'),(9,'d','d'); + + +SELECT ta.* FROM t1 AS ta, t1 AS tb +WHERE ( tb.b != ta.b OR tb.a = ta.a ) + AND ( tb.b = ta.c OR tb.b = ta.b ); + +DROP TABLE t1; set optimizer_switch= @optimizer_switch_save; === modified file 'sql/opt_range.cc' --- a/sql/opt_range.cc 2012-06-04 15:26:11 +0000 +++ b/sql/opt_range.cc 2012-07-04 10:34:45 +0000 @@ -2008,7 +2008,7 @@ int QUICK_RANGE_SELECT::init_ror_merged_ if (reuse_handler) { DBUG_PRINT("info", ("Reusing handler 0x%lx", (long) file)); - if (init() || reset()) + if (init()) { DBUG_RETURN(1); } @@ -2043,7 +2043,7 @@ int QUICK_RANGE_SELECT::init_ror_merged_ if (file->ha_external_lock(thd, F_RDLCK)) goto failure; - if (init() || reset()) + if (init()) { file->ha_external_lock(thd, F_UNLCK); file->ha_close(); @@ -2090,7 +2090,18 @@ int QUICK_RANGE_SELECT::init_ror_merged_ head->key_read= org_key_read; bitmap_copy(&column_bitmap, head->read_set); head->column_bitmaps_set(&column_bitmap, &column_bitmap); - + + if (reset()) + { + if (!reuse_handler) + { + file->ha_external_lock(thd, F_UNLCK); + file->ha_close(); + goto failure; + } + else + DBUG_RETURN(1); + } DBUG_RETURN(0); failure: _______________________________________________ commits mailing list commits(a)mariadb.org https://lists.askmonty.org/cgi-bin/mailman/listinfo/commits ----- End forwarded message ----- -- BR Sergei -- Sergei Petrunia, Software Developer Monty Program AB, http://askmonty.org Blog: http://s.petrunia.net/blog

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