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Displaying posts with tag: commit (reset)
The strange commit behavior and the invisible Xid_log_event

Did you see this when you are migrating from your lovely MySQL 5.1 to MySQL 5.5?
Oh, sorry, you remain attached to your pretty 4.1. Yes, I know, MyISAM has become so important in your life…

Ok, seriously, I would like to share this little observation I made recently when switching to MySQL 5.5 on one slave.
You can see below two graphs for the transactional activity, there is exactly the same volume of update, delete and insert queries :

MySQL 5.1

MySQL 5.5

But the gray area represents the number of commit per second.
I find that I have much more commit with MySQL 5.5, why? …

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MySQL 5.6 Replication – New Early Access Features

At OSCON 2011 last week, Oracle delivered more early access (labs) features for MySQL 5.6 replication. These features are focused on better integration, performance and data integrity:

- The Binlog API: empowering the community to seamlessly integrate MySQL with other applications and data stores;

- Binlog Group Commit and Enhanced Multi-Threaded Slaves: continuing to deliver major improvements to replication performance;

- Durable Slave Reads: further enhancing data integrity.

These new features build on the significant replication enhancements announced as part of the MySQL 5.6.2 Development Milestone Release back in April.

We are always listening to our customers and community. And, based on their needs and input, the MySQL engineering team continues to take …

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A rollback query on innodb does not reset the auto_increment counter?!?!?

So, this is a small blog that I felt necessity to do cause I am seeing many tweets on twitter (obviously) talking about that “a rollback query on innodb does not reset the auto_increment counter”. I quickly went test it and really didn’t understand what happened with this user environment, due to it I decided [...]

Implicit COMMIT considered harmful.

If you execute the following, what does your RDBMS do?

CREATE TABLE t1 (a int);
START TRANSACTION;
INSERT INTO t1 (a) VALUES (1);
START TRANSACTION;
INSERT INTO t1 (a) VALUES (2);
ROLLBACK;
SELECT * FROM t1;

The answer may surprise you.

Benchmarking MySQL ACID performance with SysBench

A couple of question I get a lot from MySQL customers is “how will this hardware upgrade improve my transactions per second (TPS)” and “what level of TPS will MySQL perform on this hardware if I’m running ACID settings?” Running sysbench against MySQL with different values for per-thread and global memory buffer sizes, ACID settings, and other settings gives me concrete values to bring to the customer to show the impact that more RAM, faster CPUs, faster disks, or cnf changes have on the server. Here are some examples for a common question: “If I’m using full ACID settings vs non-ACID settings what performance am I going to get from this server?”

Let’s find out by running sysbench with the following settings (most are self explanatory – if not the man page can explain them):

  • sysbench –test=oltp –db-driver=mysql –oltp-table-size=1000000 –mysql-engine-trx=yes –oltp-test-mode=complex …
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Showing entries 1 to 5