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10 Newer Entries Showing entries 91 to 100 of 947 10 Older Entries

Displaying posts with tag: Uncategorized (reset)

MySQL Enterprise Monitor 3.0: viewing Query Analyzer for 5.5.x servers.
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So, the good thing about MEM 3.0 is that it’s agentless, i.e. you don’t need an agent to use Query Analyzer data and see when performance is at it’s worst and dive into the offending SQL’s and explain plans to see what’s happening.

That’s great, however, sometimes it’s not always an easy road to migrate to 5.6 and even if you’re doing so, there’s nearly always a time when you want to continue viewing things in 5.5.x and compare performance between the 2.

The thing is, that in order to see the Explain Plans we need 5.6.14 or upwards (and setting “UPDATE …

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Introducing the MySQL High Availability Blog
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Welcome to the MySQL High Availability Blog. This blog is maintained by the High Availability team at Oracle to give our readers a bit of inside information regarding various topics around the MySQL high availability features.

MySQL 5.7 & Fabric in Sunnyvale May 22nd
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MySQL Fabric and 5.7 will be the topics of presentations this Thursday (5/22) at the Plug and Play Tech Center in Sunnyvale, California. Lee Stigile is presenting: What’s new in MySQL 5.7, and Sastry Vendantam is presenting MySQL Fabric.

Agenda is as follows:

5:00-5:30 Networking/Socialize over food and drinks
5:30-6:00 Lee will present MySQL 5.7
6:00-6:30 Sastry will present Fabric
6:30-7:00 Q&A and Socialize over food and drinks

Here is the link to register/RSVP




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Triggers — MySQL 5.6 and 5.7
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MySQL Triggers are changing in 5.7 in a big way. Triggers have been around since 5.0 and have not changed much up to 5.6 but will gain the ability to have multiple triggers on the same event. Previously you had ONE trigger maximum on a BEFORE UPDATE, for example, and now you can have multiple triggers and set their order.

So what is a trigger? Triggers run either BEFORE or AFTER an UPDATE, DELETE, or INSERT is performed. You also get access to the OLD.col_name and NEW.col_name variables for the previous …

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Re-factoring some internals of prepared statements in 5.7
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When the MySQL server receives a SELECT query, the query goes through several consecutive phases:

  • parsing: SQL words are recognized, the query is split into different parts following the SQL grammar rules: a list of selected expressions, a list of tables to read, a WHERE condition, …
  • resolution: the output of the parsing stage contains names of columns and names of tables. Resolution is about making sense out of this. For example, in “WHERE foo=3“, “foo” is a column name without a table name; by applying SQL name resolution rules, we …
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MySQL EXPLAIN Explained
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In years past, MySQL was a bit of a black box when it came to understanding what was happening and why. In MySQL 5.6 and 5.7, we’ve added many new features that provide much needed transparency and insight into the inner workings of MySQL. The single biggest feature was the new Performance Schema, but some other examples are:

  1. The ability to see what query generated a row based binary log event.
  2. The ability to …
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Interview with John Partridge, President & CEO of Tokutek, Inc.
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“As the database gets used, shards can grow at an uneven rate and one shard might carry a majority of the load. MongoDB corrects this by balancing shards, but because of MongoDB’s lack of concurrency this operation can stall the database unacceptably.”–John Partridge.

I have interviewed John Partridge, President & CEO of Tokutek, Inc.

RVZ

Q1. Tokutek recently announced to have eliminated performance issues of MongoDB sharding. What was the problem?

John …

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Slides from PLMCE 2014 breakout session
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As many of you already know, PLMCE is an annual MySQL
community conference and Expo organized by Percona in the month of April
(usually). It is a great conference, not only to meet new and eminent people in
MySQL and related database fields, but also to attend interesting talks, and
also to give some.

This year I spoke about synchronous replication at a higher level. The talk was
titled …





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MySQL file limit, table cache and max_connections
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MySQL variables open_files_limit, table_open_cache and max_connections are
inter-related, and this is for obvious reasons: all deal with file descriptors
one way or another.

If one of the value is provided but others are left out, mysqld calculates
others using a formula and in some cases, emits a warning if not possible.

The whole calculation behind obtaining the final file descriptor limit is a bit
byzantine and is as follows (for Linux):





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Use MySQL to store NoSQL and SQL data in the same database using memcached and InnoDB
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MySQL is a great relational database, but at some point someone (management) in your company is probably going to say that they need to use NoSQL to store their data. After all, NoSQL is one of the latest buzzwords, so it must be good (correct?). Basically, NoSQL allows you to store data without all of the characteristics of a relational database. A very simple explanation is that you are storing all of a data set with just one primary key, and the primary key is how you also retrieve the data. While NoSQL may be good in some cases, it is hard to beat …

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10 Newer Entries Showing entries 91 to 100 of 947 10 Older Entries

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