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Displaying posts with tag: configuration (reset)
Building MySQL Server with CMake on Linux/Unix

CMake is a cross-platform, open-source build system, maintained by Kitware, Inc.

From the home page:

CMake is a family of tools designed to build, test and package software. CMake is used to control the software compilation process using simple platform and compiler independent configuration files. CMake generates native makefiles and workspaces that can be used in the compiler environment of your choice.

It has been used for building the MySQL Server on Windows since MySQL 5.0 – the initial CMake build support was added in August 2006.

For …

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Quick reminder: avoid using binlog-do-db

Nothing new about this warning; but it’s worth repeating:

Using binlog-do-db is dangerous to your replication. It means the master will not write to binary logs any statement not in the given database.

Ahem. Not exactly. It will not write to binary logs any statement which did not originate from the given database.

Which is why a customer, who was using Toad for MySQL as client interface to MySQL, and by default connected to the mysql schema, did not see his queries being replicated. In fact, he later on got replication errors. If you do:

USE test;
INSERT INTO world.City VALUES (...)

Then the statement is assumed to be in the test database, not in the world database.

Slightly …

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To not yum or to not apt-get?

I’ve written shortly on this before. I like yum; I love apt-get; I prefer not to use them for MySQL installations. I consider a binary tarball to be the best MySQL installation format (source installations being a different case altogether).


I use yum and apt-get whenever I can and for almost all needs (sometimes preferring CPAN for Perl installations). But on a MySQL machine, I avoid doing so. The reason is either dependency hell or dependency mismatch.

Package managers are supposed to solve the dependency hell issue. But package managers will rarely have an up to date MySQL version.

I’ve had several experiences where a simple yum installation re-installed the MySQL version. I’ve had …

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MySQL Cluster Configurator v3

Version 3.0 of the severalnines/Configurator has been released:

  • Improved scripts (a lot of cleanup), prefixing the script output with the hostname:
    Cluster: Cluster Start
    ps-ndb01: Starting management server (nodeid=1)
    ps-ndb01: Copying ../config/config.ini to /etc/mysql
    ps-ndb01: Started management server (nodeid=1, pid=28253)

  • Reduced number of scripts --> --initial --> --initial
    start-ndbd-<host>-<id> --> start-ndbd-<host>-<id>.sh --initial
  • Better error handling during rolling …
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Be sure to know your my.cnf [sections]

The MySQL configuration file, e.g. /etc/my.cnf has a number of different section headings including [mysql], [mysqld], [mysqld_safe]. It is important that you ensure you put the right variables into the right section. For example, the following my.cnf configuration file will not operate as the user probably expects.

query_cache_size = 100M
query_cache_type = 1



In this example, this configuration does not give you a MyISAM key buffer of 600M, it’s actually the default of 8M.

mysql> show global variables like 'key_buffer_size';
| Variable_name   | Value   |
| key_buffer_size | 8388600 |

Be sure to add the right options to the [mysqld] section.

What I didn’t know until yesterday was that some programs read from …

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Announcing mycheckpoint: lightweight, SQL oriented monitoring for MySQL

I’m proud to announce mycheckpoint, a monitoring utility for MySQL, with strong emphasis on user accessibility to monitored data.

mycheckpoint is a different kind of monitoring tool. It leaves the power in the user’s hand. It’s power is not with script-based calculations of recorded data. It’s with the creation of a view hierarchy, which allows the user to access computed metrics directly.

mycheckpoint is needed first, to deploy a monitoring schema. It may be needed next, so as to INSERT recorded data (GLOBAL STATUS, GLOBAL VARIABLES, MASTER STATUS, SLAVE STATUS) — but this is just a simple INSERT; anyone can do that, even another monitoring tool.

It is then that you do not need it anymore: everything is laid at your fingertips. Consider:

SELECT innodb_read_hit_percent, DML …
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MySQL and hardware information

People often ask “what’s the best hardware to run a database on?” And the answer, of course, is “it depends”. With MySQL, though, you can get good performance out of almost any hardware.

If you need *great* performance, and you have active databases with a large data set, here are some statistics on real life databases — feel free to add your own.

We define “large data set” as over 100 Gb, mostly because smaller data sets have an easier time with the available memory on a machine (even if it’s only 8 Gb) and backups are less intrusive — InnoDB Hot Backup and Xtrabackup are not really “hot” backups, they are “warm” backups, because there is load on the machine to copy the data files, and on large, active servers we have found that this load impacts query performance. As for how active a database is, we’ve found that equates to a peak production load of over 3,000 queries per second on a transactional …

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Configuring for large databases in MySQL Cluster

If you need to create a big database into MySQL Cluster with:

  • A lot of tables indexes, columns, and tables
  • A lot of records

there are a few things to think about:

  • If a table has > ~90M records, you have to create the table with MAX_ROWS=<amount of records in table anticipating growth>:
    CREATE TABLE t1(...) ENGINE=ndbcluster MAX_ROWS=200000000;
    This way the data node will allocate more partitions for the table, since there is a limitation in how many records that can be stored in one partition (and the limit is around 90M records).
  • Many tables / table objects --> Make sure you increase MaxNoOfTables (kernel limit is 20320 tables). This creates a table object pool of size MaxNoOfTables.
    • Each table you create will use one table object. …
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MySQL related bookmark collection

I am publishing my MySQL related bookmark collection

Feel free to send me links you think might be good to add in order to help others.

Remember, SHARING IS CARING!!! …. we get so much for free, why shouldn’t we give some back?


Have you checked your MySQL error log today?

As a consultant I would be rich if I made money every time when asking “Have you checked the MySQL error log?”

Today’s special found in a 13GB MySQL server error log.

090819 22:49:37InnoDB: Warning: difficult to find free blocks from
InnoDB: the buffer pool (1101071 search iterations)! Consider
InnoDB: increasing the buffer pool size.
InnoDB: It is also possible that in your Unix version
InnoDB: fsync is very slow, or completely frozen inside
InnoDB: the OS kernel. Then upgrading to a newer version
InnoDB: of your operating system may help. Look at the
InnoDB: number of fsyncs in diagnostic info below.
InnoDB: Pending flushes (fsync) log: 0; buffer pool: 0
InnoDB: 167 OS file reads, 1 OS file writes, 1 OS fsyncs
InnoDB: Starting InnoDB Monitor to print further
InnoDB: diagnostics to the standard output.
090819 22:49:37InnoDB: Warning: difficult to find free blocks from
InnoDB: the buffer pool (1101051 search iterations)! Consider
InnoDB: increasing …
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