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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...]
Probably the best European conference on MySQL is coming this fall
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The full schedule for Percona Live London 2014 was revealed earlier this month.
Congratulation to all selected speakers and a big thanks to those who submitted a talk.

I have many reasons to believe that this conference will be a very good year.
Let me explain why:

A community event made by community members

If you didn’t know who selected the talks for the conference, have a look to the conference committee page.
This committee is a perfect mixed between community members and evangelists.
As chairman of this conference, I can say that these guys made an amazing job to rate and comment this huge amount of  submitted talks.

I particularly want to point out that despite





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Ambiguous column names (not that kind)
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Time for another quiz to impress your friends, if you have that kind of friends.

The manual page in question

mysql --skip-enable-disable-column-names=0 -e "select 1"
mysql --skip-disable-enable-column-names=0 -e "select 1"
mysql --loose-disable-enable-skip-column-names=0 -e "select 1"

What's the result? An error about unknown options? A warning? Column headers enabled? Disabled?

Answer ▼

mysql --skip-enable-disable-column-names=0 -e "select 1"
+---+
| 1 |
+---+
| 1 |
+---+

mysql --skip-disable-enable-column-names=0 -e "select 1"
+---+
| 1 |
+---+

mysql --loose-disable-enable-skip-column-names=0 -e "select 1"
mysql: option '--skip-column-names' cannot take an argument

The Query Rewrite Plugins
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Why Query Rewrites?

Now that the cost model project is progressing, most of you are going to notice execution plan changes. In the vast majority of the cases, the changes will be for the better, and some bugs with a long history will finally be closed. In some cases, however, you will notice that your queries run slower. This is inevitable: even if the MySQL optimizer is doing a much better job with the information it has, it may still be the case that the information was incomplete and that the best plan was, in fact, found by not trusting that information! Normally, we would just say “add an optimizer hint” and be over with it. But sometimes you can’t do that. For instance your query could be auto-generated from an application that you have no control over.

  [Read more...]
Replication from Oracle to MariaDB the simple way - Part 4
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Now it's time to get serious about replicating to MariaDB from Oracle, and we are real close now, right? What I needed was a means of keeping track of what happens in a transaction, such as a LOG table of some kind, and then an idea of applying this log to MariaDB when there is a COMMIT in Oracle. And thing is, these two don't have to be related. So I can have a table which I write to and also have a Materialized View that is refreshed on COMMIT on, and I need a log table or something. And when the Materialized View is refreshed, as there is a COMMIT, then the log can be applied. From a schematic point-of-view, it looks something like this:

  [Read more...]
Connector/Python 2.1 with C Extension using Connector/C
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In time for Oracle OpenWorld 2014, we released Connector/Python 2.0. We also released a labs release Connector/Python 2.1 and we have a new feature: a C Extension which uses Connector/C.

This C Extension is an optional, alternative to the pure Python MySQL Client protocol implementation. One of the reasons to implement it was to improve performance in some situations, for example, when huge result sets are returned. Pure Python is still default, if C Extension is not available.

The following post will get your through downloading and installing the MySQL Connector/Python 2.1.0 labs release.

Requirements

  • Windows users at of luck;
  [Read more...]
MySQL Workbench 6.2: Fabric and Client Connection Browser
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MySQL Fabric Support

MySQL Fabric (http://www.mysql.com/products/enterprise/fabric.html" target="_blank) servers can now be added to the Workbench home screen. When clicked, these connections will dynamically query the Fabric server and individual connections for all the managed MySQL servers will be created. You can then connect to each instance as usual. 

Metadata Lock Browser

MySQL uses metadata locking to manage access to objects (tables, triggers, and so forth). Sometimes that can be puzzling, as your query may block waiting on an object being manipulated by another connection from maybe another user. The Client Connections list was updated

  [Read more...]
Online Truncate of InnoDB UNDO Tablespaces
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We have received a lot of requests from our user community regarding the ability to  truncate UNDO tablespaces (‘truncate’ here means that the size of the tablespace is reset back to what it was when it was first created). We are happy to say that we’ve now been able to implement this anticipated feature.

Introduction

The InnoDB UNDO tablespace(s) host rollback segments that hold rollback information related to database changes. This information is used to rollback a transaction and to retrieve the previous version of a record that has been updated or deleted for multi-version concurrency control (MVCC). Once a transaction is committed, InnoDB will discard the related UNDO log records. UNDO log records for updates or deletes will be kept around as long as there exists an open transaction that may access older versions of the records. When all

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MySQL Group Replication – Transaction life cycle explained
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The multi master plugin for MySQL is here. MySQL Group Replication provides virtually synchronous updates on any node in a group of MySQL servers, with conflict handling and automatic group membership management and failure detection.

For a better understanding on how things work, we go under the hood in this post and will analyse the transaction life cycle on multi master and which components does it interact with. But before that we need to understand first what a group is.

Group Communication Toolkit

The multi master plugin is powered by a group communication toolkit. This is what decides which servers belong to the group, performs failure detection and orders server messages. Being the ordered messaging the magic thing that allows the data to be consistent across all nodes. You can check the details of the group communication

  [Read more...]
Showing entries 1 to 10 of 33191 10 Older Entries

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