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Displaying posts with tag: Savepoint (reset)
Fun with Bugs #37 - Bugs fixed in MySQL 5.6.27

MySQL 5.6.27 was released on September 30 formally. Source code is also available on GitHub, and I have it compiled (some users are less lucky) and running for a couple of days already. In this post I'll comment on some bugs reported by MySQL Community that are fixed there.

I'd like to start with a couple of bugs where patches were also contributed. First of all, the fix suggested by Stewart Smith in Bug #72811, "Set NUMA mempolicy for optimum mysqld performance", helps to allocate memory in a more reasonable way on NUMA-enabled systems. Previously it was like all interleaved or nothing, now there is a way to apply this only …

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SAVEPOINTs just got more problematic

A few days ago I reported on a problem with savepoints, but all that it appeared to be was an extemporaneous warning message. Well, I just found out that InnoDB can actually lose the savepoints! The overall transaction can still be rolled back successfully, but the savepoints themselves are completely gone. This only occurs after the warning: "Got error 153 from storage engine" happens twice in one transaction (if it only happens once, the savepoints still work) which requires that alternating savepoints be set 6 times. See the full report here: http://bugs.mysql.com/bug.php?id=38187.

Error 153 when creating savepoints

One of our developers ran into the strangest error a few days ago, which neither the MySQL manual nor Google searching could find any information on. When he called certain stored procedures in a certain order, he got "Error 153 returned from storage engine." It's been reduced to a very simple test case, and a bug report has been filed. Here's the test case:

DROP TABLE IF EXISTS foo;
CREATE TABLE `foo` (
`a` int(11) NOT NULL auto_increment,
PRIMARY KEY (`a`)
) ENGINE=InnoDB;

begin;
insert into foo values();
savepoint a1;
insert into foo values();
savepoint a2;
insert into foo values();
savepoint a1;
insert into foo values();
savepoint a2;
show warnings;
rollback;

The very last "savepoint" generates the warning "Got error 153 from storage engine". Any other MySQL'ers use savepoints and …

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Reporting MySQL Internals with Information Schema plug-ins

Last week, I described how to use the MySQL plug-in API to write a minimal 'Hello world!' information schema plug-in. The main purpose of that plug-in is to illustrate the bare essentials of the MySQL information schema plug-in interface.

In this article, I'd like to take that to the next level and demonstrate how to write an information schema plug-in that can access some of the internals of the MySQL server. For this particular purpose, we will focus on a plug-in that reports all the SAVEPOINTs available in the current session. This …

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Showing entries 1 to 4