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[Maria-developers] MariaDB scalability: mutexes
by Sergey Vojtovich 16 Apr '14

16 Apr '14

Hi Axel, I benchmarked various mutexes available to MariaDB. Results are here: http://svoj-db.blogspot.ru/2014/02/mariadb-mutexes-scalability.html Among other things I noticed that normal mutexes scale better than adaptive. And it looks like it gives over 5 000 TPS in my benchmarks: Original -------- 64 threads, time spent: 60s, queries executed: 11500723, qps: 191678, 1 thread qps: 2994, tps: 13691 64 threads, time spent: 60s, queries executed: 10983665, qps: 183061, 1 thread qps: 2860, tps: 13075 64 threads, time spent: 60s, queries executed: 11080325, qps: 184672, 1 thread qps: 2885, tps: 13190 slow LOCK_open -------------- 64 threads, time spent: 60s, queries executed: 12948365, qps: 215806, 1 thread qps: 3371, tps: 15414 64 threads, time spent: 60s, queries executed: 13191584, qps: 219859, 1 thread qps: 3435, tps: 15704 64 threads, time spent: 60s, queries executed: 13050647, qps: 217510, 1 thread qps: 3398, tps: 15536 slow LOCK_open + THR_LOCK::mutex -------------------------------- 64 threads, time spent: 60s, queries executed: 15863174, qps: 264386, 1 thread qps: 4131, tps: 18884 64 threads, time spent: 60s, queries executed: 15761944, qps: 262699, 1 thread qps: 4104, tps: 18764 64 threads, time spent: 60s, queries executed: 15773239, qps: 262887, 1 thread qps: 4107, tps: 18777 Could you do official benchmarks (patch attached)? It would be nice to also benchmark MySQL-5.6 with thr_lock part of the patch. Thanks, Sergey

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[Maria-developers] Error on 'make' of mariadb source
by Kesha Shah 14 Apr '14

14 Apr '14

Hi all, I did some changes with in the sql_yacc.yy. During building the source , I am getting following error (attached screenshot) when I try to execute the "make" command after doing a cmake of the source. It says permission denied while trying to make jemalloc-configure. Although i am executing the make command with root user. [image: Inline image 1] [image: Inline image 2] Can somebody provide/help me with some pointers on how to proceed to resolve it ? -- Thanks and Regards, Kesha Shah. www.keshashah.com

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[Maria-developers] MariaDB release and support policies
by Otto Kekäläinen 14 Apr '14

14 Apr '14

Hello! Does MariaDB promise a 8 year release cycle for 5.5 as MySQL does? Does all of the points listed at https://lists.ubuntu.com/archives/technical-board/2014-February/001812.html apply for MariaDB as well? Can we promise Ubuntu that all MariaDB minor releases fulfill the quality requirements listed above? If so, I'll then file a micro release update permission request for Ubuntu. AFAIK as I know it is the only way to get security releases to users anyway. PS. Do you people know about semver.org and try to follow the general versioning policy? -- Check out our blog at http://seravo.fi/blog and follow @ottokekalainen

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[Maria-developers] Third bunch of unmerged items
by Sergey Vojtovich 14 Apr '14

14 Apr '14

Hi Sergei, here comes third bunch of items which I'm unsure about: WL#5706/Bug#58712/Bug#11746378 - Encrypt or remove passwords from slow, query, and binary logs WL#4677 - Unique Server Ids for Replication Topology (UUIDs) WL#6004 - Server extension for allowing user tables to be put into transactional SE Bug #14112682 : MYSQLTEST: PROVIDE ACCESS TO ERROR NAMES THROUGH NUMERIC CODES AND VICE VERSA Bug #11747313 31741: MYSQLTEST - DEPRECATE "SYSTEM" COMMAND WL#2739: Auditing Password Security (plugin + API) WL#6587: disconnect_on_expired_password WL#5825 Using C++ Standard Library with MySQL code WL#2111: #6 Set CLASS_ORIGIN and SUBCLASS_ORIGIN Regards, Sergey

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Re: [Maria-developers] MariaDB 10.x GTID
by Kristian Nielsen 11 Apr '14

11 Apr '14

Jan Lindström <jplindst(a)mariadb.org> writes: > some background, lets assume we have two galera clusters that are > geographically distributed (lets say for example that cluster A is on Europe > and cluster B on USA). Inside a cluster all nodes are set up so that server_id > and domain_id are the same and we will use strict GTID mode (for a example on > cluster A server_id = 1 and domain_id =1 and in cluster B server_id = 2 and > domain_id = 2). In cluster we naturally use Galera replication. Additionally, > we have asynchronous replication (MySQL replication) between these clusters. > 1) We would like to have some special domain_id (i.e. GTID) for transactions > that are executed only on certain cluster e.g. on cluster A. This would mean > that there is some dynamic option to enable "local" transaction execution mode, > where transactions are executed on cluster A but not on cluster B. I know that > this kind of feature does not exists but is it even possible ? Basically, this > would mean for MySQL replication point of view a fact that if GTID is formed > like this special GTID, they are not replicated to slave, but they are written > to binlog. It sounds like what you want is some option on the slave that would cause it to ignore all GTIDs with some specific domain id, similar to how it is currently possible to filter on server id. That seems a reasonable request; such option does not exist currently though. Another option is to use the @@skip_replication variable. Set this for the sessions doing the "local" transactions. Then set replicate_events_marked_for_skip to either FILTER_ON_SLAVE or FILTER_ON_MASTER, as you like. This is specifically designed to allow to log certain transactions to the binlog but not replicate them, so it sounds like it is what you asked for. > 2) There will be some challenge in maintaining the sequence number for GTID > correctly: for global GTID purposes, we can just count commits, and skip every > local transaction commit, but, we must also initialize the sequence for every > node joining the cluster. In MySQL-5.6 this happens by copying binlog files > (only header part needed) to joining node. I wonder if same strategy works for > MGC-10, is MariaDB GTID is stored in binlog header ? Yes, the GTID is stored in the binlog header. It is also stored in a file master-bin.state. This file is read at server start to initialise the GTID sequence numbers. However, if the file is not found for any reason, the information is extracted from the last binlog file (the master-bin.state is just a cache). However, you need the whole binlog file (if master-bin.state is missing), not just the header. I am sure it must be the same for MySQL-5.6 - you need to scan to the end of the binlog file, as there may be extra GTIDs logged in the file that were not there when the header was written. Of course, just after server start, the most recent binlog file is empty, so just the header works. It sounds like you would want to just copy over the master-bin.state file. However, this whole approach sounds wrong to me. The current GTID state is a cluster-wide property, not a local property, I do not understand why you want to maintain it locally. As I understand it, Galera decides on commit order. The certification process decides for parallel transactions T1 and T2 which one will be committed before the other. The GTID sequence has to match the commit order. So the GTIDs need to be generated by Galera, at the point in the code where the commit order is decided. This Galera code then also needs to do the binlog writing, so that binlog order matches GTID order and commit order. With Galera handling GTID number allocations, I do not understand why you would need to worry about binlog headers. But maybe I have misunderstood, I do not know Galera in details. Maybe you could explain how Galera ensures matching commit order, binlog order, and GTID order? Or alternatively, explain how things work without such ensurance? > 3) Independent table (in data dictionary) or file for replication filters. I > can change the replication filters dynamically, but if the server crash and i > don?t report to my.cnf it?s lost. Therefore, there is a need to store > replication filters persistently and these should be loaded automatically when > server is restarted. Currently we do not have this, replication filters are configuration options, and those are stored in the config file, not in dynamic tables or files. The server_id filters are set by CHANGE MASTER though, IIRC, so they are stored in master.info / relay_log.info. > 4) Dynamic binlog. Currently options are read-only. This we do not have. There has been talk of allowing it under global read lock; this might work, but it would require some work to carefully check all of the code for possible issues. There are a lot of places in the code where expensive synchronisation/locking is avoided based on the knowledge that the binlog can not be enabled or disabled on-the-fly. Hope this helps, - Kristian.

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[Maria-developers] debugging MDEV-5932, wrong result set for tokudb
by Rich Prohaska 10 Apr '14

10 Apr '14

Hello, TokuDB generates an empty result set for a select with sub-select, but generated a non-empty result set for the same query when creating a new table. The result set should be the same in both cases. What is going on here? InnoDB computes an empty result set for both cases. I traced the problem to the tokudb::index_read function. The tokudb::index_read does not handle the null byte key prefix. Unfortunately, I do not understand how the null byte (byte 0) in the key handed to the ::index_read function is supposed to work. Most of the time, the value of this byte is 0. Sometimes it is set to 1. How should the storage engine work WRT this? BTW, this problem exists with TokuDB in MySQL 5.5.36, MySQL 5.6.16. I have not been able to consistently see this on MariaDB 5.5.36 for some reason. In any case, I am interested in how the handler's index_read function is supposed to process the null byte. Thanks

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[Maria-developers] Buildbot machines
by Rasmus Johansson 09 Apr '14

09 Apr '14

Hi, I discussed both with Dbart and Serg last week about the situation with buildbot. Kristian and Elena also had similar discussion on IRC today. To sum it up, there seems to be two aspects to it; 1) more machines, i.e. slaves could/should be added immediately and 2) some development work could/should be done on buildbot to support some other ways of building, like automatically spinning up and down platform specific virtual machines in a public cloud somewhere whenever they are needed. I looked into alternatives for the 1) immediate need of more machines and thought. I found a pretty interesting alternative from OVH.COM, who offers dedicated servers to a very reasonable price. Here is a good example of what they can offer: https://www.ovh.com/us/dedicated-servers/infra/2014-EG-32.xml . I would be prepared to give it a try. Do you think the specs are good enough to help with the load buildbot currently has? BR, Rasmus -- Rasmus Johansson, VP Engineering MariaDB | t: +358 50 499 9589 | Skype: ratzpo

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Re: [Maria-developers] [Commits] Rev 3991: MDEV-5138 Numerous test failures in "mtr --ps --embedded"
by Sergei Golubchik 09 Apr '14

09 Apr '14

Hi, Alexey! On Apr 02, Alexey Botchkov wrote: > > Still, another question, why did you have to rename net_store_data() to > > net_store_data_cs() ? > > That's personal. > I really don't like functions with exactly same names - makes code harder to > understand and debug. > Do you belive it's better not to rename these here? That's up to you. Sometimes I create functions with the same name, sometimes I don't. For example, tdc_acquire_share() - there are few functions with the same name, because they do exactly the same. Actually, one of tdc_acquire_share() is a real function, others are inline convenience wrappers - they eventually call the "real" one. But tdc_acquire_share_shortlived() - while also only a convenience wrapper - has a different name to emphasize that it has different semantics. But anyway, that's your patch. If you'd like to rename - go ahead. Regards, Sergei

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[Maria-developers] INT thread variables in mysql and mariadb (all versions as far as i know)
by Rich Prohaska 09 Apr '14

09 Apr '14

suppose that I have a THDVAR_INT variable with min = -1 and max = 1, and i set it to -1. how come select @@var returns 4294967295 instead of -1?

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[Maria-developers] Error in "make install"
by sriram patil 09 Apr '14

09 Apr '14

Hello all, I have had built and installed the mariadb source code before, no hassles whatsoever. I was trying to install it again but getting the following error when trying to "make install" ....... -- Installing: /usr/local/mysql/mysql-test/././var/tmp -- Installing: /usr/local/mysql/mysql-test/././var/tmp/mysqld.2 -- Installing: /usr/local/mysql/mysql-test/././var/tmp/mysqld.1.sock CMake Error at mysql-test/cmake_install.cmake:36 (FILE): file INSTALL cannot copy file "/home/sriram/Downloads/mariadb/10.0/mysql-test/./var/tmp/mysqld.1.sock" to "/usr/local/mysql/mysql-test/././var/tmp/mysqld.1.sock". Call Stack (most recent call first): cmake_install.cmake:119 (INCLUDE) make: *** [install] Error 1 I have changed the owner and group of the folder "/usr/local/mysql", so root access is not an issue. I am using Ubuntu 12.04. Did anyone get such error while installing and was able to solve it? Thanks, Sriram

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