Showing entries 1 to 7
Displaying posts with tag: shard-query (reset)
WarpSQL now has SQL shim plugins

I made some improvements to the 'proxy' inside of MySQL 5.7 that I've created for WarpSQL (Shard-Query 3).  I've made the MySQL proxy/shim pluggable and I moved the SQLClient to sql/  I've merged these changes into 'master' in my fork.

Now you can create "SQL shim" plugins (SHOW PASSWORD is implemented in plugin/sql_shim) and install them in the server like regular plugins:

-- command doesn't work
mysql> show password;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'password' at line 1

-- install the example sql_shim plugin:
mysql> install plugin sql_shim soname '';                                                                 Query OK, 0 rows affected (0.00 sec)

-- now the command works
mysql> show password;
|  |
|  |
1 row in set (0.00 sec)

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SQL injection in the MySQL server! (of the proxy kind)

[this is a repost of my blog post, because it did not syndicate to]

As work on WarpSQL (Shard-Query 3) progresses, it has outgrown MySQL proxy.  MySQL proxy is a very useful tool, but it requires LUA scripting, and it is an external daemon that needs to be maintained.  The MySQL proxy module for Shard-Query works well, but to make WarpSQL into a real distributed transaction coordinator, moving the proxy logic inside of the server makes more sense.

The main benefit of MySQL proxy is that it allows a script to "inject" queries between the client and server, intercepting the results and possibly sending back new results to the client.  I would like similar functionality, but inside of the server.

For example, I would like to implement new SHOW commands, and these commands do not need to be …

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Parallel Query for MySQL with Shard-Query

While Shard-Query can work over multiple nodes, this blog post focuses on using Shard-Query with a single node.  Shard-Query can add parallelism to queries which use partitioned tables.  Very large tables can often be partitioned fairly easily. Shard-Query can leverage partitioning to add paralellism, because each partition can be queried independently. Because MySQL 5.6 supports the partition hint, Shard-Query can add parallelism to any partitioning method (even subpartioning) on 5.6 but it is limited to RANGE/LIST partitioning methods on early versions.

The output from Shard-Query is from the commandline client, but you can use MySQL proxy to communicate with Shard-Query too.

In the examples I am going to use the schema from the Star Schema Benchmark.  I generated data for scale factor 10, which means about 6GB of data in the largest table. I am going to show a few different queries, and …

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Shard-Query supports background jobs, query parallelism, and all SELECT syntax

SkySQL just blogged about a tool to schedule long running MySQL jobs, prevent too many queries from running simultaneously, and stores the results in tables.  It even uses Gearman.  You will note that the article says that it uses PAQU, which uses Shard-Query.

I think PAQU was created for two reasons.  A) Shard-Query lacked support for fast aggregation of STDDEV and VARIANCE (this has been fixed), and B) their data set requires “cross-shard queries”.  From what I can see though, their type of cross-shard queries can be solved using subqueries in the FROM clause using Shard-Query, instead of using a customized (forked) version of Shard-Query.  It is unfortunate, because my recent improvements to Shard-Query have to be ported into PAQU by the PAQU authors.

I’d like to encourage you to look at Shard-Query if you need to run complex jobs in the background and get the results later.  As a bonus, you …

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Shard-Query 2.0 Beta 1 released

It is finally here.  After three years of development, the new version of Shard-Query is finally available for broad testing.

This new version of Shard-Query is vastly improved over previous versions in many ways.  This is in large part due to the fact that the previous version of Shard-Query (version 1.1) entered into production at a large company.  Their feedback during implementation was invaluable in building the new Shard-Query features.   The great thing is that this means that many of the new 2.0 features have already been tested in at least one production environment.

This post is intended to highlight the new features in Shard-Query 2.0.  I will be making posts about individual features as well as posting benchmark results.

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Shard-Query EC2 images available

Infobright and InnoDB AMI images are now available

There are now demonstration AMI images for Shard-Query. Each image comes pre-loaded with the data used in the previous Shard-Query blog post. The data in the each image is split into 20 “shards”. This blog post will refer to an EC2 instances as a node from here on out. Shard-Query is very flexible in it’s configuration, so you can use this sample database to spread processing over up to 20 nodes.

The Infobright Community Edition (ICE) images are available in 32 and 64 bit varieties. Due to memory requirements, the InnoDB versions are only available on 64 bit instances. MySQL will fail to start on a micro instance, simply decrease the values in the /etc/my.cnf file if you really want to try micro instances.

The storage worker currently logs too much …

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Intra-query parallelism for MySQL queries without an appliance or closed source database

*edit* I want to point out that this test was done on a single database server which used MySQL partitioning. This is a demonstration of how Shard-Query can improve performance in non-sharded databases too.*edit*.

Over the weekend I spent a lot of time improving my new Shard-Query tool ( and the improvements can equate to big performance gains on partitioned data sets versus executing the query directly on MySQL.

I'll explain this graph below, but lower is better (response time) and Shard-Query is the red line.

MySQL understands that queries which access data in only certain partitions don't have to read the rest of the table. This partition elimination works well, but MySQL left a big optimization out of partitioning: …

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Showing entries 1 to 7