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[Maria-developers] [GSoC] Week Five!
by sriram patil 23 Jun '14

23 Jun '14

Hi All, Following is the link to my blog post of fifth week into GSoC. http://goo.gl/x7dtcn Suggestions and/or review are welcome! Thanks, Sriram

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[Maria-developers] Java Connector Coding till 21st June
by Puneet Dewan 21 Jun '14

21 Jun '14

Hi Everyone. Test case class(ServersidePreparedStatementTest.java) was written for checking the value of statement id. This week code review was done by Massimo and Georg. There pointers were really valuable as data was not being send in a proper format to the server for execute(com_stmt_execute) method : 1.NullBitMap was set incorrectly. 2.Creation of a new class extending PacketOuptutStream e.g integer of 4 bytes can be sent.Currently if an integer is sent it is sent as a byte. 3.Also I was expecting when we do a *prepare* for a statement like insert into XYZ(id) values(?) where id is of type Integer. Then server shall be returning integer as a type. This was a false assumption.It does not return the type. So now on the basis of value set for *id as example*,decide on the type to be sent from execute. So this week will fix the above things. Looking forward for suggestions. Regards Puneet.

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Re: [Maria-developers] [Commits] 22f532c: MDEV-4260 Don't create frm files for temporary tables
by Sergey Vojtovich 20 Jun '14

20 Jun '14

Hi Sergei, ok to push. One note inline. On Fri, Jun 20, 2014 at 11:29:36AM +0200, serg(a)mariadb.org wrote: > revision-id: 22f532cfb2f40132e2f7b079a3aafb109af92c26 > parent(s): fb8818c1aff9ce67b74f965c019cad93addd811e > committer: Sergei Golubchik > branch nick: maria > timestamp: 2014-06-20 11:29:12 +0200 > message: > > MDEV-4260 Don't create frm files for temporary tables > > * Don't write frm for tmp tables > * pass frm image down to open_table_uncached, when possible > * don't use truncate-by-recreate for temp tables - cannot recreate > without frm, and delete_all_rows is faster anyway > * remove HTON_FLUSH_AFTER_RENAME (BDB-ism, unused for years) > > --- > mysql-test/r/temp_table_frm.result | 20 +++++++++++ > mysql-test/t/temp_table_frm.test | 13 ++++++++ > sql/handler.h | 2 +- > sql/sql_base.cc | 14 +++++++- > sql/sql_base.h | 3 +- > sql/sql_table.cc | 27 +++------------ > sql/sql_truncate.cc | 68 +------------------------------------- > sql/unireg.cc | 3 +- > 8 files changed, 56 insertions(+), 94 deletions(-) > ...skip... > diff --git a/sql/sql_base.cc b/sql/sql_base.cc > index 0558066..7d69ccb 100644 > --- a/sql/sql_base.cc > +++ b/sql/sql_base.cc > @@ -5561,7 +5563,17 @@ TABLE *open_table_uncached(THD *thd, handlerton *hton, > strend(saved_cache_key)+1, tmp_path); > share->db_plugin= ha_lock_engine(thd, hton); > > - if (open_table_def(thd, share, GTS_TABLE | GTS_USE_DISCOVERY)) > + /* > + Use the frm image, if possible, open the file otherwise. > + > + The image might be unavailable in ALTER TABLE, when the discovering > + engine took over the ownership (see TABLE::read_frm_image). > + */ > + int res= frm->str > + ? res= share->init_from_binary_frm_image(thd, false, frm->str, frm->length) Excessive "res="? Regards, Sergey

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[Maria-developers] [GSoC] Week Four!
by sriram patil 19 Jun '14

19 Jun '14

Hi All, Sorry for a little delay in posting the blog link this week. Following is the blog link about my fourth week into GSoC. http://goo.gl/W54cvE Suggestions and/or reviews are welcome! Thanks, Sriram

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Re: [Maria-developers] [Commits] Rev 4258: MDEV-6039 - WebScaleSQL patches in lp:maria/10.0
by Sergei Golubchik 18 Jun '14

18 Jun '14

Hi, Sergey! On Jun 18, Sergey Vojtovich wrote: > At lp:maria/10.0 > > ------------------------------------------------------------ > revno: 4258 > revision-id: svoj(a)mariadb.org-20140618141504-kqq6ws9gm93r2b2d > parent: svoj(a)mariadb.org-20140618081243-jxs6yo9tx9cahdv6 > committer: Sergey Vojtovich <svoj(a)mariadb.org> > branch nick: 10.0 > timestamp: Wed 2014-06-18 18:15:04 +0400 > message: > MDEV-6039 - WebScaleSQL patches > > Stop spawning dummy threads on client library initialization > > Let's revert the fix for Bug#24507. To quote Monty from 2006: > > "After 1/2 a year, when all glibc versions are updated, we can delete > this code." > > Note: The upstream glibc bug was fixed in 2006. Ok to push Regards, Sergei

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Re: [Maria-developers] [GSoC] self-tuning optimizer
by Sergei Golubchik 18 Jun '14

18 Jun '14

Hi, Anshu! Please, don't forget to cc: maria-developers@ when discussing development topics. On Jun 18, Anshu Avinash wrote: > > What I meant to say was we need N "linearly independent" equations to > solve for N variables and that might not be the case. Some of the > queries might not use any factor at all or use one factor more often. Yes, you're right, of course. > > Later we'll see what to do - perhaps we'll need to decrease the limit, > > or set it exactly to N (which means, the solution won't be "best > > fitting" anymore). But this will be not in this GSoC, not your project. > > I'm sure that in this project we won't have enough factors for memory > > usage to become an issue :) > > Yes, I'll start with a basic least squares fitting model without caring > much about the memory usage for now. Sounds good. Regards, Sergei

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Re: [Maria-developers] [GSoC] self-tuning optimizer
by Sergei Golubchik 18 Jun '14

18 Jun '14

Hi, Anshu! On Jun 18, Anshu Avinash wrote: > Hi serg, > > Sorry that I had been out of touch for 1-2 days. I got caught up in some > other work. > > I have read through the comments you made on MDEV and I have just started > the implementation for the first approach, the approximate method. I have > pushed a prototype at: > https://github.com/igniting/server/commit/3bd4f5b6fd20d11575207ac36e8a3cc2c… > > Here is what I'm thinking, we add to the array of measurement data, after > each query and try to solve the system of equations because we don't know > when the system of equations would become solvable. Eh. To solve a system of linear equations with N unknowns, you need N equations. So, you wait until you get N equations and solve it. Few thoughts: 1. it might be that out of all factors that you have in your data structures (currently it's 2 + 2 * MAX_HA), only few will be actually used in queries (for example, only TIME_FOR_COMPARE and read_time for InnoDB). Then you only need two queries to solve that, not 2+2*MAX_HA. But it's an optimization, try to do the basic implementation without it first. 2. You normally store these data (for N queries) in the THD, right? It might be that the thread will disconnect before it'll do the required number of queries. To avoid throwing the useful data away, you can store one extra set of data globally and when some THD disconnects and it doesn't have enough data to solve the equation, you append this data to the global set and solve that as a whole. Again, this is an extension, only do it when the basic implementation works. > However this might be time consuming, trying to solve equations after > each query. Can we store the entire data (from all the queries) and > apply a best fitting model, instead of solving them exactly? This we > will do at disconnect. I don't have a good answer for that. It's a trade-off. Either you collect exactly N equations and solve them. Then you collect the next N equations (or you get another one and delete the first one) - and solve that. And so on. Or you collect many equations, more than N. And find a best fitting solution. This way you do less solving, but you'll need more memory. I think, for now you can do that - use a best fitting solution. We only have very few factors at the moment. Still, even now you'll need some limit to how many equations you'll collect. Later we'll see what to do - perhaps we'll need to decrease the limit, or set it exactly to N (which means, the solution won't be "best fitting" anymore). But this will be not in this GSoC, not your project. I'm sure that in this project we won't have enough factors for memory usage to become an issue :) > Should it be in ~THD() or somewhere else? Yes, ~THD is fine, just make sure you only do it for real connection THD's, where SELECT queries were issues and optimizer was run. Not for various internal THD's, like the one you create in cost_factors::init. For example, as you've noticed, I've mentioned in the last comment about using read_time() result and Nrows_estimated (the same applies to scan_time(), of course). So, when ha_read_time() is called, you need to remember (in your data set) the return value of read_time() and Nrows_estimated (that's the last argument of read_time()). This way, you only solve your equations if you have this read_time() and Nrows_estimated (or scan_time()) stored. If not - the optimizer was never run and you don't do anything. Regards, Sergei

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Re: [Maria-developers] [Commits] Rev 4257: Empty commit to check email setting in commit mails in http://bazaar.launchpad.net/~maria-captains/maria/10.0
by Roberto Spadim 18 Jun '14

18 Jun '14

working :) 2014-06-18 7:53 GMT-03:00 <knielsen(a)knielsen-hq.org>: > At http://bazaar.launchpad.net/~maria-captains/maria/10.0 > > ------------------------------------------------------------ > revno: 4257 > revision-id: knielsen(a)knielsen-hq.org-20140618105333-44ez01iye29sljur > parent: knielsen(a)knielsen-hq.org-20140618090308-frd0tuo8rycgyi32 > committer: Kristian Nielsen <knielsen(a)knielsen-hq.org> > branch nick: work-10.0 > timestamp: Wed 2014-06-18 12:53:33 +0200 > message: > Empty commit to check email setting in commit mails > _______________________________________________ > commits mailing list > commits(a)mariadb.org > https://lists.askmonty.org/cgi-bin/mailman/listinfo/commits > -- Roberto Spadim SPAEmpresarial Eng. Automação e Controle

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[Maria-developers] [MDEV-4903] Regarding range support for multi-column IN predicates
by Sergey Petrunia 18 Jun '14

18 Jun '14

Hi, So, MySQL 5.7 has got support for range optimization for multi-column IN predicates: http://optimize-this.blogspot.ru/2013/12/range-access-now-in-in-predicate-n… We've also got a user issue about it: https://mariadb.atlassian.net/browse/MDEV-4903. I'm looking at their IN handling. I don't see anything apparently wrong with it. They don't process multi-column NOT IN, but one can say that they just have a limited scope. Relevant code in opt_range.cc for single-column IN: case Item_func::IN_FUNC: { Item_func_in *func=(Item_func_in*) cond_func; if (inv) { // complicated code to handle NOT IN } else { tree= get_mm_parts(param, cond_func, field, Item_func::EQ_FUNC, func->arguments()[1], cmp_type); if (tree) { Item **arg, **end; for (arg= func->arguments()+2, end= arg+func->argument_count()-2; arg < end ; arg++) { tree= tree_or(param, tree, get_mm_parts(param, cond_func, field, Item_func::EQ_FUNC, *arg, cmp_type)); } } } mysql-5.7 extends this approach to handle multi-column case (by invoking get_mm_parts() for each compared value, then doing tree_and(), and then tree_or()). Should we just go ahead and backport it? BR Sergei -- Sergei Petrunia, Software Developer MariaDB | Skype: sergefp | Blog: http://s.petrunia.net/blog

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[Maria-developers] problem with update and myisam
by Roberto Spadim 18 Jun '14

18 Jun '14

hi guys, could anyone help me with https://mariadb.atlassian.net/browse/MDEV-6355 thanks -- Roberto Spadim

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