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10 Newer Entries Showing entries 41 to 50 of 33318 10 Older Entries
Recover orphaned InnoDB partition tablespaces in MySQL
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A few months back, Michael wrote about reconnecting orphaned *.ibd files using MySQL 5.6. I will show you the same procedure, this time for partitioned tables. An InnoDB partition is also a self-contained tablespace in itself so you can use the same method described in the previous post.

To begin with, I have an example table with a few orphaned partitions and we will reconnect each partition one by one to the original table.

mysql [localhost] {msandbox} (recovery) > SHOW CREATE TABLE t1 G
*************************** 1. row ***************************
Table: t1
Create Table: CREATE TABLE `t1` (
KEY `h_date` (`h_date`)
/*!50100 PARTITION BY RANGE (year(h_date))
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libAttachSQL 0.9.0 RC - Connection Groups
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It has been just over 4 months since I started working on libAttachSQL for HP's Advanced Technology Group. Today marks the first (and hopefully only) RC release of the library.

Connection Groups

The only real new feature that has been added to 0.9.0 is the concept of connection groups which is something I'm pretty excited about. Internally libAttachSQL uses event loops to supply the non-blocking API. Connection Groups join a bunch of connections together into a group that uses a single event loop. This makes things much more efficient internally and makes applications easier to code too.

Here is a simplified example of how to use it (for a more detailed example see our example in the documentation).

First we

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InnoDB General Tablespaces – Preview
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The new InnoDB Labs release contains the ability to create and use independent multi-table general tablespaces.

This feature will provide a way to group tables together into tablespaces at a location and filename of your choosing.  Tables using row formats of Redundant, Compact, and Dynamic can be combined together into the same general tablespace. Compressed tables with the same key_block_size can also be combined together.

The SQL syntax for creating an empty general tablespaces is:

CREATE TABLESPACE `tblspace_name` ADD DATAFILE 'tablespace.ibd' [FILE_BLOCK_SIZE=n];

The filename can contain an

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Sysbench cached updates: MySQL 5.7 vs previous releases
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I used MySQL 5.7.5 to repeat tests I did for MySQL 5.7.2 and 5.6.10 with the sysbench client and a cached database to compare performance for low and high concurrency. My configuration was optimized for throughput rather than crash safety. The performance summary:
  • MySQL 5.7.5 is 1.47X slower than 5.0.85 at 1 thread
  • MySQL 5.7.5 is a bit slower than 5.6.21 at 8 and 16 threads
  • MySQL 5.7.5 is faster than others at 32 threads

I used my sysbench 0.4 fork and set the value of the c column to 0 in the sbtest tables as that column is incremented during the test. The

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How to avoid hash collisions when using MySQL’s CRC32 function
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Percona Toolkit’s  pt-table-checksum performs an online replication consistency check by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master – and the tool pt-table-sync synchronizes data efficiently between MySQL tables.

The tools by default use the CRC32. Other good choices include MD5 and SHA1. If you have installed the FNV_64 user-defined function, pt-table-sync will detect it and prefer to use it, because it is much faster than the built-ins. You can also use

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Today’s startups: assemble at your own risk
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I was talking with Todd Hoff recently over at High Scalability about a trend I’ve seen of late. ME: I really liked this post by Zoli Kahan from  AWS, cloudflare, docker, haproxy, mysql, mongo, memcache, ansible.  They use just about every technology being talked about these days.   Todd: Yah, that’s why I asked […]
orchestrator 1.1.18: new features, support for orchestrator-agent
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Outbrain's orchestrator 1.1.18 is released:

  • Support for orchestrator-agent (see announcement): agent pages, support for agent actions, initiation of seeds (provisioning of new/corrupted servers), auditing of seeds.
  • Clusters dashboard
  • Support for long query auditing
  • SSL
  • Proxy authentication (e.g. apache2 serving as reverse-proxy with LDAP)
  • User control
  • Better slave moving rules.

Quick links:

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Announcing orchestrator-agent
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orchestrator-agent is a side-kick, complementary project of orchestrator, implementing a daemon service on one's MySQL hosts which communicates with and accepts commands from orchestrator, built with the original purpose of providing an automated solution for provisioning new or corrupted slaves.

It was built by Outbrain, with Outbrain's specific use case in mind. While we release it as open source, only a small part of its functionality will appeal to the public (this is why it's not strictly part of the orchestrator project, which is a general purpose, wide-audience solution). Nevertheless, it is a simple implementation of a daemon, such that can be easily extended by

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#DBHangOps 10/16/14 -- MySQL SYS, Graphs, and more!
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#DBHangOps 10/16/14 -- MySQL SYS, Graphs, and more!

Hello everybody!

Join in #DBHangOps this Thursday, October, 16, 2014 at 11:00am pacific (18:00 GMT), to participate in the discussion about:

  • New in TokuDB 7.5 (rescheduled for next time!)
  • MySQL SYS features and discussion -- what do you want to see in MySQL SYS?
  • What graphs make a good dashboard?

You can check out the event page at on Thursday to participate.

As always, you can still watch the #DBHangOps twitter search, the @DBHangOps twitter feed, or this blog post to get a link for the google hangout on Thursday as well.

See all of you on Thursday!

Page read performance: MySQL 5.7 vs previous releases
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For this test I used sysbench to determine the peak rate for disk reads per second from InnoDB with fast storage. Fast storage in this case is the OS filesystem cache. I want to know the peak for MySQL 5.7.5 and whether there is a regression from 5.6. My summary is:
  • 5.7.5 is 12% to 15% worse than 5.6.21 at 1 thread. I hope we can fix this via bug 74342.
  • 5.7.5 is 2% to 4% worse than 5.6.21 at 8, 16 and 32 threads
  • 5.6/5.7 are much better than 5.0 especially at high concurrency
  • Page size (16k, 8k, 4k) has a big impact on the peak only when compression is used. 

The test server has 40 hyperthread cores and is shared by the sysbench client and mysqld server.

I used my sysbench 0.4

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10 Newer Entries Showing entries 41 to 50 of 33318 10 Older Entries

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