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10 Newer Entries Showing entries 61 to 70 of 131 10 Older Entries

Displaying posts with tag: bugs (reset)

Granting privileges may break replication in MySQL 5.6.10
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MySQL lets database administrators define access rights on many levels – from the ability to run global commands down to access to individual columns. Some rights can be applied to many different objects, such as for example SELECT or UPDATE, which can be granted globally or restricted only to certain databases or tables, while others are only meant for one specific purpose. An example of the latter could be FILE privilege, which permits user to interact with the file system from inside a database instance. It only makes sense as the global right and not anywhere else.

As any other activity that produces changes, GRANT …

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17 Famous MySQL Bug Reporters
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Every good bug report at http://bugs.mysql.com matters and may have important findings or useful information inside (even if it is declared as "Not a bug" or "Unsupported"), but based on my experience reports from some people should become a mandatory reading for both MySQL users who care about there servers, and Oracle engineers who process bugs.

Let me name a few of these people, "Top 17" of them based on my totally non-scientific, experience-based approach. You can click on the name to see the list of all bugs reported by this person, started from the recent ones (this may help to …

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Fun with Bugs, Issue #5, February 2013
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This week we had finally got MySQL 5.6.10 released as GA. It's a big deal, first MySQL GA release with the entire development process happened in Oracle from day one, quantum leap (as every second blog post says these days) in many areas, from scalability to replication performance, with InnoDB fulltext indexes and PERFORMANCE_SCHEMA improvements in between... So, this week it makes sense to concentrate on 5.6 GA and nothing else.

As one of my former colleagues noted, no GA is bug free. Surely there are known and verified bugs in 5.6.10, but not that many. Let me just give you a list to check, in case you plan to upgrade/switch …

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Fun with Bugs, Issue #4, January 2013
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This post will cover bugs I've "escalated" on Facebook during the period from January 28 till January 31. There were several serious bug reports noted, but many were taken from this great page that was created by Hartmut and updates every day. I had to find new source of fun, as Oracle reduced number of open and unassigned server bugs even more and processes new ones really fast this week. So, let's speak about some "Oldies but Goldies"...

I'd like to start with  …

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Fun with Bugs, Issue #3, January 2013
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This week in my posts on Facebook I paid attention mostly to bugs in MySQL 5.6.x, as I really expected to see 5.6 GA announcement soon. Maybe some of the bugs were the reason to postpone release a bit. Anyway, let's start with serious bug reports and some trends I've noted.

I've noted that some of "Verified" bug reports somehow silently miss comments about their status in MySQL 5.6. Check Bug #68137, for example. It is repeatable on 5.5.31 (yet to be released, but it means 5.5.30 is …

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Fun with Bugs, Issue #2, January 2013
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Looks like Issue #1 was popular enough based on number of reviews, so let me continue and tell you what kinds of fun I had with MySQL bug reports between January 12 and today. Once again, this is a kind of digest for my bugs related posts on Facebook during this period.

I'd like to start with the latest open bug at the moment, Bug #68127. Looks like one can easily crash MySQL 5.6.9 by running few concurrent  SELECT * from threads queries against PERFORMANCE_SCHEMA. As …

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Life cycle of a MySQL bug
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I had already written once on how to report bugs to http://bugs.mysql.com to have high chances for the bug report to be noted and processed fast. But why this matters at all? Because chances are high that bug report will never be opened and read by any MySQL developer in Oracle while its status is just "Open"! This is a short answer.

If you are surprised (the story is different with, say, Percona Server …

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How to use PERFORMANCE_SCHEMA to check InnoDB mutex waits
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SummaryTo set up InnoDB mutex waits monitoring via PERFORMANCE_SCHEMA in general with MySQL 5.6.9 you should do at least the following:

  1. Start MySQL server with all mutex related instruments enabled at startup (performance_schema=ON by default on recent 5.6.x), like this:

    mysqld_safe --performance_schema_instrument='wait/synch/mutex/innodb/%=on' &
  2. Connect to server and set up proper consumers explicitly, like this:

    UPDATE performance_schema.setup_consumers SET enabled = 'YES' WHERE name like 'events_waits%';
  3. Run your problematic load. …





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MySQL, the strange case of a timestamp field
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I discovered a feature (or bug) of MySQL timestamp fields. Maybe is documented in some place what I not read yet:

When I add a new timestamp field to a table, MySQL magically adds some features to new timestamp field like a “trigger” and a default value to CURRENT_TIMESTAMP.

There is test-case script:

-- CREATING TABLE AND INSERT SOME DUMMY DATA
mysql> CREATE TABLE t(
    -> id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
    -> val VARCHAR(50)
    -> );
Query OK, 0 ROWS affected (0.15 sec)
 
mysql> INSERT INTO t (val) VALUES ("foo") ,("var");
Query OK, 2 ROWS affected (0.08 sec)
Records: 2  Duplicates: 0 …
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My take on privatized MySQL security bugs
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A couple weeks ago I submitted Bug #67315: Crashing server by stored function referencing user defined variable in query. If you press that link, you can't see the bug (though I can as I submitted it).

This is due to Oracle's policy for security-related bugs. Tomas Ulin, Vice President MySQL Development at Oracle , was kind enough to discuss Oracle's policy with me, and these are the key points as I understand them:

Oracle's basic approach is to protect its customers. By publicizing security-bugs, Oracle's customers are vulnerable to black hatters attacks. …

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10 Newer Entries Showing entries 61 to 70 of 131 10 Older Entries

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