Yearly Archives - 2015

Percona XtraBackup 2.3.3 is now available

Percona is glad to announce the release of Percona XtraBackup 2.3.3 on December 17th, 2015. Downloads are available from our download site or Percona Software Repositories.
Percona XtraBackup enables MySQL backups without blocking user queries, making it ideal for companies with large data sets and mission-critical applications that cannot tolerate long periods of downtime. […]

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Using dbsake to recover table structure from .frm files and process mysqldump output

We work on data recoveries quite often. In many cases, we recover table structures from the .frm files because there was no backup available. There is already a great blog post by my colleague Miguel Ángel Nieto about how we can recover structures from .frm files using MySQL utilities.
This works pretty well and we prefer […]

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Act Quickly for Percona Live Super Saver rate – Plus an added incentive!

Our Super Saver discount rate for Percona Live 2016 is only available ‘til December 31st! This rate gets you all the excellent and amazing opportunities that Percona Live offers, at a discount.
The Percona Live Data Performance Conference is the premier open source event for the data performance ecosystem. It is the place to be […]

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MongoDB 3.2 WiredTiger in iiBench

MongoDB 3.2 was recently released with WiredTiger as the default storage engine.
In just over five years, MongoDB has evolved into a popular database. MongoDB 3.0 supported “pluggable storage engines.” The B-Tree-based WiredTiger should outperform IO-optimized RocksDB and PerconaFT in in-memory workloads, but it demonstrates performance degradation when we move into IO workloads.
There are reports that WiredTiger 3.2 […]

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used_columns: EXPLAIN FORMAT=JSON tells when you should use covered indexes

In the “MySQL Query tuning 101” video, Alexander Rubin provides an excellent example of when to use a covered index. On slide 25, he takes the query
select name from City where CountryCode = ’USA’ and District = ’Alaska’ and population > 10000 and adds the index
cov1(CountryCode, District, population, name) on table
City. With Alex’s query […]

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Percona Server 5.7.10-1 first RC available

Percona is glad to announce the first release candidate of Percona Server 5.7.10-1 on December 14, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories.
This release contains all the bug fixes from latest Percona Server 5.6 release (currently Percona Server 5.6.27-76.0).
New Features:

Percona Server 5.7.10-1 is not available on RHEL 5 […]

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rows_examined_per_scan, rows_produced_per_join: EXPLAIN FORMAT=JSON answers on question “What number of filtered rows mean?”

At the end of my talk “Troubleshooting MySQL Performance” at the LinuxPiter conference, a user asked me a question: “What does the EXPLAIN ‘filtered’ field mean, and how do I use it?” I explained that this is the percentage of rows that were actually needed, against the equal or bigger number of resolved rows. While the user was […]

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attached_condition: How EXPLAIN FORMAT=JSON can spell-check your queries

When you work with complicated queries, especially ones which contain subqueries, it is easy to make a typo or misinterpret column name. While in many cases you will receive a 
column not found error, sometimes you can get strange results instead.
Like finding 4079 countries in Antarctica:


mysql> select count(*) from City where CountryCode in (select CountryCode from Country […]

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Percona Server 5.6.27-76.0 is now available

Percona is glad to announce the release of Percona Server 5.6.27-76.0 on December 4, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories.
Based on MySQL 5.6.27, including all the bug fixes in it, Percona Server 5.6.27-76.0 is the current GA release in the Percona Server 5.6 series. Percona Server is open-source […]

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