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Displaying posts with tag: mysql (reset)

MySQL 5.6.21 Overview and Highlights
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MySQL 5.6.21 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here.

For this release, there was 1 “InnoDB Notes” and 1 “Functionality Added or Changed” bug fix (and 0 “Security Fix”), so not much there, but of course they should be noted:

  • InnoDB Note: The –skip-innodb option is now deprecated and its use results in a warning. It will be removed in a future MySQL release. This also applies to its synonyms (–innodb=OFF, –disable-innodb, and so forth).
  • Functionality Added: Internally, spatial data types such as Geometry are represented as BLOB values, so when invoked with the –hex-blob option, mysqldump now displays spatial values in hex. (Bug
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    libAttachSQL Benchmarks With Sysbench
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    This week I have been spending a little bit of time creating a module for Sysbench so that it can use libAttachSQL as a database driver. The reason for doing this is twofold:

  • Brian (my boss at HP's Advanced Technology Group) said now would be a good time to benchmark libAttachSQL
  • I really needed more than a few basic queries to shake out bugs in the library, and a benchmark is a good way to shove a few million through it
  • On the bug front, it did find a total of 5 bugs, a couple of them serious. Which is great, the more testing and bug finding the better. These have all been fixed in GitHub and will be part of the upcoming 0.5.0 release.

    The Test Setup

    To

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    HAProxy: Give me some logs on CentOS 6.5!
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    HAProxy is frequently used as a load-balancer in front of a Galera cluster. While diagnosing an issue with HAProxy configuration, I realized that logging doesn’t work out of the box on CentOS 6.5. Here is a simple recipe to fix the issue.

    If you look at the top of /etc/haproxy/haproxy.cfg, you will see something like:

    global
        log         127.0.0.1 local2
    [...]

    This means that HAProxy will send its messages to rsyslog on 127.0.0.1. But by default, rsyslog doesn’t listen on any address, hence the issue.

    Let’s edit /etc/rsyslog.conf and uncomment these lines:

    $ModLoad imudp
    $UDPServerRun 514

    This will make rsyslog listen on UDP port 514 for all IP

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    Generated Columns in MySQL 5.7.5
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    Generated Columns is a new feature available in the latest lab release. This work is based on a contribution by Andrey Zhakov. Thanks, Andrey! The Optimizer team modified it to follow the current MySQL design, and to lift a number of limitations.

    The syntax is:

    <type>   [ GENERATED ALWAYS ]   AS   ( <expression> )   [ VIRTUAL|STORED ]
    [ UNIQUE [KEY] ]   [ [PRIMARY] KEY ]   [ NOT NULL ]   [ COMMENT <text> ]

    There are two kinds of Generated Columns: virtual (default) and stored. Virtual means that the column will be calculated on the fly when a record is read from a table. Stored means that


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    Low-concurrency performance for point lookups: MySQL 5.7.5 vs previous releases
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    My series on low-concurrency performance continues. Previously I compared results for sql-bench and here I use point queries run by mysqlslap for 1, 4 and 32 concurrent clients to compare MySQL versions 5.0, 5.1, 5.5, 5.6 and 5.7 for the InnoDB and Heap storage engines. All binaries (mysqlslap, mysqld) ran on the same host. The test table has 64,000 rows. The test binaries are described here. Compared to MySQL 5.0.85, for the workload with 1 thread:

    • Response time for 5.7.5 is 1.47X worse without the PS and 1.51X worse with the PS
    • Response time for 5.6.21 is 1.37X worse without


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    libAttachSQL Benchmarks With Sysbench
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    libAttachSQL Benchmarks With Sysbench

    This week I have been spending a little bit of time creating a module for Sysbench so that it can use libAttachSQL as a database driver. The reason for doing this is twofold:

  • Brian (my boss at HP’s Advanced Technology Group) said now would be a good time to benchmark libAttachSQL
  • I really needed more than a few basic queries to shake out bugs in the library, and a benchmark is a good way to shove a few million through it
  • On the bug front, it did find a total of 5 bugs, a couple of them serious. Which is great, the more testing and bug finding the better. These have all been fixed in GitHub and will be part of the upcoming

      [Read more...]
    InnoDB Native Partitioning – Early Access
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    The InnoDB labs release includes a snapshot of the InnoDB Native Partitioning feature.

    To better understand why we implemented this, we need to start with some background on tables, storage engines, and handlers. In MySQL an open instance of a table has a handler object as an interface to the table’s storage engine. For a partitioned table there is a main table handler that implements the partitioning feature, but for storage, each partition has its own handler. This worked fairly well, but the more partitions you had the more overhead from the per partition handlers. So to remove this overhead for partitioned InnoDB tables we’re introducing Native Partitioning support! This means a new InnoDB partitioning aware handler, so that we have a single handler object for a partitioned table and not one handler object per

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    Visualizing the impact of ordered vs. random index insertion in InnoDB
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    [This post refers to innodb_ruby version 0.9.11 as of October 2, 2014.]

    Many DBAs know that building indexes in “random” order (or really any order that greatly differs from ordered by key) can be much less efficient. However, it’s often hard to really understand why that is. With the “-illustrate” visualization modes available in innodb_ruby, it’s possible to quite easily visualize the structure of indexes. The space-lsn-age-illustrate mode to innodb_space allows visualization of all pages in a space file by “LSN age”, generating something like a heatmap of the space file based on how recently each page was modified.

    (Note that a

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    Single thread performance in MySQL 5.7.5 versus older releases via sql-bench
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    MySQL 5.7 does much better on benchmarks with high-concurrency. It might do worse on benchmarks with low-concurrency. I am not surprised as this has been true across many releases. The question is whether anything can be done to reverse it. When testing 5.6 I filed bugs 68825 and 69236 for this problem. Maybe it is time for new bug reports. I measure the following from sysbench for InnoDB but must add the disclaimer that I have yet to explain these results and I am wary of unexplained benchmark results. And also note that these overheads are for the sql-bench workload. Your workload might have a smaller overhead. By the same token, if you have less overhead when running TPC-D queries that  [Read more...]
    Is the HTTP Plugin for MySQL secure?
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    The HTTP Plugin for MySQL offers three APIs: REST-like CRUD, REST-like JSON DOCUMENT and SQL. The SQL API lets you run any SQL you want. Including, for example, DROP mysql.users if you mess up your setup. Insecure? It depends on your viewpoint.

    It’s more than just another protocol…

    On the first look HTTP is just another network protocol for sending requests to MySQL. HTTP is the protocol of the web. Whether you need to integrate MySQL in a larger setup and use web services for data exchange or you want to access MySQL from a JavaScript client that is restricted to HTTP/Websocket. HTTP is the natural choice. CouchDB convinced many when it introduced the idea.

    HTTP Client   Standard client |   |  [Read more...]
    10 Newer Entries Showing entries 61 to 70 of 16449 10 Older Entries

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