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Re: Question about GTIDs in MariaBD
With autocommit=1 every statement runs in its own transaction, so
obviousluy .. yes!
MyISAM is/used to be completely 'transaction-agnosstic'. But GTIDs seem
to confict with non-transactional storage engines (as far as I can
understand). MySQL/Oracle have "solved" (!) this by not allowing updates to
tables using transactional engines and non-transactional storage engines
in same transaction.
However to me it is nonsense that transactions apply (have any effect at
all) for non-transactional storage engines. As a consequence I consider
this solution (what must have been enforced in the server layer and not the
storeage engine layer) by Oracle 'a dirty hack' (unless somewone can
explain me why it it necessary).
On Sun, May 11, 2014 at 4:42 PM, Roberto Spadim <roberto@xxxxxxxxxxxxx>wrote:
> With autoclmmit=1 works?
> Em domingo, 11 de maio de 2014, Peter Laursen <peter_laursen@xxxxxxxxxx>
> Thanks for the reply, but I am afraid I don't fully understand.
>> Here is a simple test case with mySQL 5.6.17:
>> You need all those in configuration [mysqld) section
>> gtid_mode = ON
>> enforce_gtid_consistency = ON
>> Then this small script will reproduce:
>> DROP DATABASE IF EXISTS `gtid_test`;
>> CREATE DATABASE `gtid_test`;
>> USE `gtid_test`;
>> CREATE TABLE `tab1` (
>> `a` INT DEFAULT NULL
>> ) ENGINE=MYISAM ;
>> CREATE TABLE `tab2` (
>> `b` INT
>> ) ENGINE=INNODB;
>> --start a transaction
>> SET autocommit=0;
>> INSERT INTO `tab1` VALUES (1);
>> INSERT INTO `tab2` VALUES (1);
>> -- now the first UPDATE to the MyISAM table in the transaction triggers
>> this error:
>> UPDATE `tab1` SET `a` = 5 WHERE `a` = 1;
>> -- and you'll get:
>> -- Error Code: 1785
>> -- When @@GLOBAL.ENFORCE_GTID_CONSISTENCY = 1, updates to
>> non-transactional tables can only be done in either autocommitted
>> statements or single-statement transactions, and never in the same
>> statement as updates to transactional tables.
>> ShouldI understand that MariaDB dos not prevent this (does not raise an
>> error), but it is still unsafe as binlog - and thus replication - may be
>> -- Peter
>> On Sat, May 10, 2014 at 6:09 PM, Pavel Ivanov <pivanof@xxxxxxxxxx> wrote:
>>> There is no such limitation in MariaDB as well as no limitation on
>>> CREATE TABLE ... SELECT.
>>> Although beware that mixing statements changing MyISAM and InnoDB
>>> tables in statement binlog mode you may get different results from the
>>> statements on slaves.
>>> On Sat, May 10, 2014 at 3:48 AM, Peter Laursen <peter_laursen@xxxxxxxxxx>
>>> > GTID implementation in MySQL 5.6 has the limitation as described here:
>>> > "nontransactional storage engines such as MyISAM cannot be made in the
>>> > statement or transaction as updates to tables using transactional
>>> > engines such as InnoDB."
>>> > If you try you will get the error:
>>> > Error Code: 1785
>>> > When @@GLOBAL.ENFORCE_GTID_CONSISTENCY = 1, updates to
>>> > tables can only be done in either autocommitted statements or
>>> > single-statement transactions, and never in the same statement as
>>> updates to
>>> > transactional tables.
>>> > Is there same or similar/other limitations with GTID in MariaDB 10?
>>> > -- Peter Laursen
>>> > -- Webyog
>>> > _______________________________________________
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> Roberto Spadim
> Eng. Automação e Controle