Search Results for: mysql set line

Why base64-output=DECODE-ROWS does not print row events in MySQL binary logs

Lately I saw many cases when users specified option --base64-output=DECODE-ROWS  to print out a statement representation of row events in MySQL binary logs just to get nothing. Reason for this is obvious: option --base64-output=DECODE-ROWS  does not convert row events into its string representation, this is job of option --verbose . But why users mix these […]

Multi-source replication in MySQL 5.7 vs Tungsten Replicator

MySQL 5.7 comes with a new set of features and multi-source replication is one of them. In few words this means that one slave can replicate from different masters simultaneously. During the last couple of months I’ve been playing a lot with this trying to analyze its potential in a real case that I’ve been […]

MySQL QA Episode 8: Reducing Testcases for Engineers: tuning reducer.sh

Welcome to MySQL QA Episode 8: Reducing Testcases for Engineers: tuning reducer.sh Advanced configurable variables & their default/vanilla reducer.sh settings FORCE_SKIPV FORCE_SPORADIC TIMEOUT_COMMAND & TIMEOUT_CHECK MULTI_THREADS MULTI_THREADS_INCREASE QUERYTIMEOUT STAGE1_LINES SKIPSTAGE FORCE_KILL Some examples FORCE_SKIPV/FORCE_SPORADIC TIMEOUT_COMMAND/TIMEOUT_CHECK Full-screen viewing @ 720p resolution recommended.

MySQL QA Episode 7: Reducing Testcases for Beginners – single-threaded reducer.sh!

Welcome to MySQL QA Episode #7 – Reducing Testcases for Beginners: single-threaded reducer.sh! In this episode we’ll learn how to use reducer.sh. Topics discussed; reducer.sh introduction/concepts Basic configurable variables & their default reducer.sh settings INPUTFILE options MODE=x TEXT=”text” WORKDIR_LOCATION & WORKDIR_M3_DIRECTORY MYEXTRA MYBASE PQUERY_MOD & PQUERY_LOC MODE5_COUNTTEXT, MODE5_ADDITIONAL_TEXT & MODE5_ADDITIONAL_COUNTTEXT How to learn more about each […]

Using Cgroups to Limit MySQL and MongoDB memory usage

Quite often, especially for benchmarks, I am trying to limit available memory for a database server (usually for MySQL, but recently for MongoDB also). This is usually needed to test database performance in scenarios with different memory limits. I have physical servers with the usually high amount of memory (128GB or more), but I am […]

New PERFORMANCE_SCHEMA defaults in MySQL 5.7.7

I thought it was worth a moment to reiterate on the new Performance Schema related defaults that MySQL 5.7.7 brings to the table, for various reasons. For one, most of you might have noticed that profiling was marked as deprecated in MySQL 5.6.7. So it is expected that you invest into learning more about Performance […]

MySQL 5.7 key features

The other day I was discussing new features of MySQL 5.7 with a Percona Support customer. After that conversation, I thought it would be a good idea to compile list of important features of MySQL 5.7. The latest MySQL 5.7.6 release candidate (RC) is out and is packed with nice features. Here’s a list of […]

Optimizer hints in MySQL 5.7.7 – The missed manual

In version MySQL 5.7.7 Oracle presented a new promising feature: optimizer hints. However it did not publish any documentation about the hints. The only note which I found in the user manual about the hints is: It is now possible to provide hints to the optimizer by including /*+ … */ comments following the SELECT, […]

Generated (Virtual) Columns in MySQL 5.7 (labs)

About 2 weeks ago Oracle published the MySQL 5.7.7-labs-json version which includes a very interesting feature called “Generated columns” (also know as Virtual or Computed columns). MariaDB has a similar feature as well: Virtual (Computed) Columns. The idea is very simple: if we store a column

in our table we may want to filter or group […]