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The MariaDB CONNECT storage engine offers access to JSON file and allows you to see a external JSON file as a MariaDB table.
A nice feature of the CONNECT storage Engine is its capability to auto discover a table structure when the table correspond to external data. In our case the CONNECT storage engine will automatically define the columns based on the JSON file hierarchical structure.
This is possible thanks to a feature of MariaDB Storage Engine API. This auto discovery feature allows a create statement to delegate the discovery of the table structure to the chosen storage engine.
Keep on reading!

Can we output content of a mariaDB table into JSON using the CONNECT Storage Engine ?
MariaDB and MySQL are not currently JSON friendly databases. The usage of JSON in MySQL is almost inexistent with the excetion of the explain JSON output and of MariaDB dynamic column dump.
There also exist a few udf (in MySQL lab area) to help manipulate JSON strings(searching, modification …).
Keep on reading!

Today while browsing through my emails I was very happy to read this email from Sergei Golubchik :

I'm happy to announce that MariaDB-10.1 tree has been completely migrated to github. Since now on
 we'll use github for the new development in MariaDB. It's, 
go on, fork it, hack around, submit pull requests. Have fun!
Older trees (10.0, 5.5, 5.3, 5.2, 5.1) are not on github - we do hope to migrate 
them too eventually, but at the moment they are still on launchpad.
If you're a maria-captain on launchpad - for you to get write access to the mariadb repository 
on github you need to tell me your github account name.
P.S.: Don't forget that 10.1 is still *pre-alpha*. You've been warned.
Mailing list:
Post to     :
Unsubscribe :
More help   :

So if you want to embark the MariaDB adventure
it is here :

Go on,
Fork it,
Hack around,
Submit pull requests.
Have fun!

MaxScale is a Proxy for the MySQL protocol built with a modular architecture.
The underlying concept of modules allows to extend the MaxScale proxy services. The current version implements Read Write splitting and Connection Load Balancing. Internally MySQL queries go through a SQL parsing phase. This gives MaxScale great capabilities regarding queries routing.
Keep on reading!

The MariaDB CONNECT Storage Engine allows to access heterogeneous data sources. In my previous post I show you how to use the MariaDB CONNECT Storage Engine to access an Oracle database. This is quite easy through the CONNECT Storage Engine ODBC table type.
Keep on reading!

MariaDB CONNECT Storage Engine allows to access heterogeneous datasourses. This includes various file formats. But this also includes ODBC accessible datasources
The CONNECT Storage Engine ODBC table type allows to access SQLite, Excel, SQL Server or Oracle databases. Some nice features of the ODBC CONNECT table type are:
- Auto discovery of table structure. This means that you do not need to specify the columns of the target table.
- Condition push down. This is an optimization that push filtering conditions to the target database. This can avoid a lot of network roundtrips.

Let us have a look and test the Oracle access through the CONNECT Storage Engine. I downloaded, unzipped and installed Oracle 11gR2 in a virtual box.
Let us start Oracle 11gR2

[oracle@centos1 ~]$ sqlplus /nolog
SQL*Plus: Release Production on Fri Nov 29 15:15:59 2013
Copyright (c) 1982, 2009, Oracle.  All rights reserved.
SQL> connect sys/manager1 as sysdba
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area  617975808 bytes
Fixed Size		    2215864 bytes
Variable Size		  377487432 bytes
Database Buffers	  230686720 bytes
Redo Buffers		    7585792 bytes
Database mounted.
Database opened.
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

Now let us start the oracle listener (this concept doest not exist in MySQL).

[oracle@centos1 ~]$ lsnrctl start
LSNRCTL for Linux: Version - Production on 29-NOV-2013 20:08:20
Copyright (c) 1991, 2009, Oracle.  All rights reserved.
Starting /u01/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version - Production
System parameter file is /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/diag/tnslsnr/centos1/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=centos1)(PORT=1521)))
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version - Production
Start Date                29-NOV-2013 20:08:20
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/diag/tnslsnr/centos1/listener/alert/log.xml
Listening Endpoints Summary...
Services Summary...
Service "orcl" has 1 instance(s).
  Instance "orcl", status UNKNOWN, has 1 handler(s) for this service...
Service "plsextproc" has 1 instance(s).
  Instance "plsextproc", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
[oracle@centos1 ~]$

On the machine with the MariaDB CONNECT Storage Engine we need to install the Oracle ODBC Driver. We obtain it through the installation of the Oracle instant client. Let us download and unzip the instant client. Installation is just unzip of the instant client zip files.


We need to add the path of the ODBC driver shared library. Let us 'vi .bash_profile' and add the required LD_LIBRARY_PATH.

CLIENT_HOME=/home/oraclec/instantclient_12_1 ; export CLIENT_HOME

On linux we also need to install the unixODBC open source ODBC driver manager :

yum install unixODBC
yum install unixODBC-devel

The configuration of the unixODBC driver manager is simple and just requires 2 files updates:

/etc/odbcinst.ini wich points the driver to the installed shared library

[Oracle 12c ODBC driver]
Description     = Oracle ODBC driver for Oracle 12c
Driver          = /home/oraclec/instantclient_12_1/

/etc/odbc.ini wich defines here the DSN that will be used for the ODBC connection

Driver       = Oracle 12c ODBC driver
ServerName   = //centos1.localdomain:1521/oracle
DSN          = orcl
UserName = scott
Password = manager1

How to test that the unixODBC + oracle ODBC driver is correctly installed ?
The unixODBC includes an ODBC client tool 'isql'. Let us use it to test our installation and the DSN we just created.

root@centos1 ~]# isql orcl scott manager1
| Connected!                            |
|                                       |
| sql-statement                         |
| help [tablename]                      |
| quit                                  |
|                                       |
SQL> select * from emp;
| EMPNO | ENAME     | JOB      | MGR   | HIREDATE           | SAL
| 7369  | SMITH     | CLERK    | 7902  | 1980-12-17 00:00:00| 800
SQLRowCount returns -1
15 rows fetched

Now let us create a CONNECT table of ODBC type. we will make this MariaDB ODBC table point to the Oracle 11g 'scott.emp' table.

[root@centos1 ~]# mysql -u root -pmanager1 -S /usr/local/mariadb10data/mariadb10.sock
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 3
Server version: 10.0.6-MariaDB-log MariaDB Server
Copyright (c) 2000, 2013, Oracle, Monty Program Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]>
MariaDB [test]> create table emp  ENGINE=CONNECT TABLE_TYPE=ODBC tabname='emp' CONNECTION='DSN=orcl;UID=scott;PWD=manager1';
ERROR 1105 (HY000): Unsupported table type ODBC

Come on ! what happened ? I just installed the latest 10.0.6 MariaDB and the CONNECT storage Engine does not support the ODBC table type. That is true and that is an issue caused by old machine being used to build the binary the unnixODBC. This problem is not present in the MariaDB 10.0.6 rpm packages. But I have multiple tar based MariaDB version installed on my Centos box(in fact a virtual box vm) and I do not want any rpm based installation. Hopefully a storage engine is just a shared library.

Let us download MariaDB-10.0.6-centos6-x86_64-connect-engine.rpm and unpack the rpm without installing it :

[root@centos1 ~]# rpm2cpio ../MariaDB-10.0.6-centos6-x86_64-connect-engine.rpm | cpio --extract  --make-directories
8216 blocs
[root@centos1 plugin]# cp ./usr/lib64/mysql/plugin/ /usr/local/mariadb10/lib/plugin/

We now have the CONNECT storage with the support of the ODBC table type. Our second try :

[root@centos1 local]# mysql -u root -pmanager1 -S /usr/local/mariadb10data/mariadb10.sock
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 3
Server version: 10.0.6-MariaDB-log MariaDB Server
Copyright (c) 2000, 2013, Oracle, Monty Program Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> use test
Database changed
MariaDB [test]> create table toto  ENGINE=CONNECT TABLE_TYPE=ODBC tabname='emp' CONNECTION='DSN=orcl;UID=scott;PWD=manager1';
ERROR 1105 (HY000): [unixODBC][Driver Manager]Can't open lib '/home/oraclec/instantclient_12_1/' : file not found

I had forgotten that the mysql service is run under the mysql linux user. This user also needs to have access to the Oracle ODBC driver ( shared library provided by the Oracle instant client).

CLIENT_HOME=/home/oraclec/instantclient_12_1 ; export CLIENT_HOME

Once done everything should goes better:

MariaDB [test]> create table toto  ENGINE=CONNECT TABLE_TYPE=ODBC tabname='EMP' CONNECTION='DSN=orcl;UID=scott;PWD=manager1';Query OK, 0 rows affected (0.79 sec)
MariaDB [test]>
MariaDB [test]> select * from toto;
| EMPNO | ENAME  | JOB       | MGR  | HIREDATE   | SAL     | COMM    | DEPTNO |
|  7369 | SMITH  | CLERK     | 7902 | 1980-12-17 |  800.00 |    NULL |     20 |
|  7934 | MILLER | CLERK     | 7782 | 1982-01-23 | 1300.00 |    NULL |     10 |
14 rows in set (0.09 sec)
MariaDB [test]> insert into toto values ( 8000,'serge','peintre',7902,'1980-12-17',123,234,20);
Query OK, 1 row affected (0.15 sec)
MariaDB [test]> select * from toto;+-------+--------+-----------+------+------------+---------+---------+--------+
| EMPNO | ENAME  | JOB       | MGR  | HIREDATE   | SAL     | COMM    | DEPTNO |
|  8000 | serge  | peintre   | 7902 | 1980-12-17 |  123.00 |  234.00 |     20 |
|  7369 | SMITH  | CLERK     | 7902 | 1980-12-17 |  800.00 |    NULL |     20 |
|  7934 | MILLER | CLERK     | 7782 | 1982-01-23 | 1300.00 |    NULL |     10 |
15 rows in set (0.03 sec)

That looks nice. I have created an ODBC table pointing to a remote Oracle 11g table. That was quite simple as the auto discovery mechanism has automatically discovered the structure of the Oracle table and converted Oracle data types to compatible mysql column type.
Let us try to update Oracle data through MySQL :

MariaDB [test]> update toto set sal=999 where empno=8000;
ERROR 1296 (HY000): Got error 174 'No DELETE/UPDATE of ODBC tablesd' from CONNECT

This is not supported ! That is right. This ODBC table update feature has been developed and is currently only available in the launchpad repository of the CONNECT Storage Engine.
CONNECT Storage Engine Sources on launchpad

The slides and replay of yesterday's webinar on the MariaDB CONNECT storage engine have just been posted. First I want to thank the numerous attendees.
You have shown great interest on the parallel execution of query on distributed MySQL Servers. I agree this is cool.
The ODBC capabilities seems also to generate interest. This make it simple to access an ODBC datasource (SQLServer, Oracle ...) from plain MySQL syntax.

Here to view the replay
Here to get the slides

Let us know about your test. You just need to download MariaDB 10.0.5 which includes the CONNECT storage engine. Give us your feedback : positive, negative, improvement requests, bugs, doc pb, ...

Here to download the latest MariaDB 10.0.5 Beta release
Here to get the CONNECT Storage Engine Documentation

MySQL Fabric is a very promising sharding framework. If I take Ulf Wendel definition of MySQL Fabric :

MySQL Fabric is an administration tool to build large “farms” of MySQL servers. In its most basic form, a farm is a collection of MySQL Replication clusters. In its most advanced form, a farm is a collection of MySQL Replication clusters with sharding on top.

So MySQL Fabric takes care of two very orthogonal features :

  • High availability of servers
  • Sharding of data

Let us forget about sharding and look at the High availability infrastructure.

Servers are included in groups, called "High Availability Groups" when we talk about HA.
Each Server has an associated Status (or Role): primary secondary, spare
Each Server has also a mode : Offline, Read-only, and Read-Write.
The implementation has been made to allow various HA implementation patterns.
The most common HA pattern is the Master/Slave HA group ( in that case we should call it a "replica set" which is the terminology used in MongoDB or Facebook MySQL Pool Scanner (MPS).

Mats Kindahl in his blog post on MySQL Fabric High Availability Groups mentioned that other HA solutions are possible for an availability group :

  • Shared Storage with SAN or NAS
  • Replicated storage like DRBD
  • MySQL Cluster shared nothing cluster

In the case of a HA group based on MySQL Cluster the group is self-managing regarding HA and MySQL Fabric does not handles the failover. With the "Shared Storage" and "Replicated storage" availability groups the secondary servers will be offline.

So one of my ideas that I hope is feasible would be to use MariaDB Galera Cluster as another HA solution with MySQL Fabric. The main advantage of this solution relates to the characteristics of MariaDB Galera Cluster. MariaDB Galera Cluster is an Active-active multi-master topology with synchronous replication. MariaDB Galera Cluster being innoDB based does not carry all the usage limitations associated with MySQL Cluster (main one being limited join capabilities).

Regarding to MySQL fabric the behavior of an availability group based on MariaDB Galera Cluster is identical to MySQL Cluster. It is a self-managing availability group.

MariaDB Galera Cluster

MariaDB Galera Cluster
Getting Started with MariaDB Galera Cluster

MySQL Fabric

MySQL Fabric: A new kid in the MySQL sharding world  2013-10-09 Serge Frezefond
MySQL Fabric: High Availability Groups  2013-10-21 Mats Kindahl
A Brief Introduction to MySQL Fabric  2013-09-21 Mats Kindahl
MySQL Fabric - Sharding - Introduction  2013-09-21 VN (Narayanan Venkateswaran)
MySQL Fabric - Sharding - Simple Example  2013-09-22 VN (Narayanan Venkateswaran)
MySQL Fabric - Sharding - Shard Maintenance  2013-09-27 VN
MySQL Fabric - Sharding - Migrating From an Unsharded to a Sharded Setup  2013-09-22 VN
Installing MySQL Fabric on Windows  2013-10-03 Todd Farmer
MySQL 5.7 Fabric: any good?  2013-09-23 Ulf Wendel

Writing a Fault-tolerant Database Application using MySQL Fabric  2013-09-21 Alfranio Junior
Sharding PHP with MySQL Fabric  2013-10-09 Johannes Schlüter
MySQL Fabric support in Connector/Python  2013-09-22 Geert Vanderkelen
MySQL Connector/J with Fabric Support  2013-09-21 Jess Balint

When full auditing is activated with the the MariaDB Audit Plugin a large volume of audit data is generated and it can put an extra burden on the server. The MariaDB audit plugin offers the two following setup variables that allow to restrict what data will be logged.

MariaDB [test]> show variables like '%audit%users';
| Variable_name               | Value                 |
| server_audit_excl_users     |                       |
| server_audit_incl_users     |                       |
14 rows in set (0.00 sec)

These variables allow to restrict the data that is going to be pushed to the audit log.
You can say: I only want to log data from these users

MariaDB [test]> set global server_audit_syslog_incl_users='proxy';

Only activities coming from the user 'proxy' will be logged.

Or you can say : I want to log data except for these users.

MariaDB [test]> set global server_audit_excl_users='user2';

No activities coming from the user 'user2' will be logged.

What happens if a user is both included and excluded ? If a user is both included and excluded database activities for that user will be logged. Include has priority over exclude. It is important to notice that the audit plugin logs data only based on the username. This username is different from the MariaDB and MySQL user definition. For them a user is combination of the username and hostname ('user'@'host').

This capability to filter audit data is crucial to avoid too much burden on the audited server and to avoid generating too much volume of audit data.

By going to the download section of  SkySQL website  some users have noticed "MariaDB Audit Plugin". This auditing feature for MySQL has been requested by more and more customers. Legal constraints make it mandatory for more and more companies to keep logging information about database access and activity.

It is very important for the MySQL community to have an open source audit plugin available. MariaDB team has always stick to the principle of keeping MySQL 100% open source and has developed the MariaDB Audit Plugin according to these principles. The MariaDB Audit Plugin has been developed using the standard MySQL Audit Plugin API. Being based on standard API makes it run both with MariaDB and with Oracle MySQL Server. The MariaDB Audit Plugin also has some unique features only available for MariaDB.

To develop this plugin we have sticked to the principle of listening to our big customer to define the specifications. This is the first version and some more improvements will come. We will be pleased to hear your feedbacks. All bug reports and critics are welcomed. The MariaDB Audit Plugin already covers the main requests that have been expressed. But we have more to come and your improvement requests are welcomed.

The purpose of the MariaDB Audit Plugin is to log the server's activity. Who connected to the server, what queries ran and what tables were touched is stored to a rotating log file. The MariaDB Audit Plugin also supports output to the widely used syslogd system. It offers the option to include/exclude users from auditing.

Oracle has released an audit plugin available through its MySQL Enterprise Server version. This make it mandatory to have an active subscription. The version you run is then a fully closed source server under a commercial license. In that case you cannot rely on third party support like SkySQL or Percona.

The MariaDB Audit Plugin is delivered as a very light shared library that can be very easily downloaded and installed on any MariaDB/MySQL server.

Where to download the MariaDB Audit Plugin ?

Source Code of the MariaDB Audit Plugin :

Pointers :
MariaDB Audit Plugin Getting started guide
MariaDB Audit Plugin documentation

My blog post on other auditing techniques
Oracle MySQL Audit Plugin
Oracle MySQL Audit Plugin doc
Macfee Audit Plugin
Macfee Audit Plugin doc