Category Archives: Generic
Introduction
Fortran (FORmula TRANslating System) is a general-purpose, imperative programming language that is especially suited to numeric computation and scientific computing. History of FORTRAN can be tracked late 1953 when John W. Backus submitted a proposal to his superiors at IBM. The First FORTRAN compiler appeared in April 1957.
Some notable historical steps where:
- FORTRAN II in 1958
- FORTRAN III in 1958,
- FORTRAN IV in 1962.
- FORTRAN 66 or X3.9-1966 become the first industry-standard
- FORTRAN 77 or X3.9-1978. This is the version of the Fortran I learned 1996.
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Last week, a SSL connection security vulnerability was reported for MySQL and MariaDB. The vulnerability states that since MariaDB and MySQL do not enforce SSL when SSL support is enabled, it’s possible to launch Man In The Middle attacks (MITM). MITM attacks can capture the secure connection and turn it into an insecure one, revealing data going back and forth to the server.
Issue resolution in MariaDB is visible through the corresponding ticket in MariaDB’s tracking system (JIRA): https://mariadb.atlassian.net/browse/MDEV-7937
The vulnerability affects the client library of the database server in both MariaDB and MySQL. But, the vulnerability does not affect all the libraries, drivers or connectors for establishing SSL connections with the server. …
Continue reading “Information on the SSL connection vulnerability of MySQL and MariaDB”
About two and a half years ago I wrote about how the MariaDB project moved bug reporting from Launchpad to JIRA. Every now and then I get contacted about how it was done and whether I would be willing to share the tools used for doing it and of course I’ve done that. Especially in one occasion the scripts were even further developed by one company that was in the process of doing exactly the same, i.e. moving bugs from Launchpad to JIRA. Thanks for the enhancements Philip Colmer from Linaro!
In Launchpad there isn’t a readymade tool for exporting bugs and I didn’t find any 3rd party tools for doing it. …
Continue reading “Scripts for migrating bug reporting from Launchpad to JIRA”
Introduction
Causal consistency [1] is one of the consistency criteria that can be used on distributed databases as consistency criteria.
Distributed database provides causal consistency if read and write operations that are causally related are seen by every node of the distributed system in the same order. Concurrent writes may be seen in different order in diffrent nodes. Causal consistency is waker than sequential consistency [2] but stronger than eventual consistency [3]. See earlier blog for more detailed description on eventual consistency https://blog.mariadb.org/eventually-consistent-databases-state-of-the-art/.
When a transaction performs a read operation followed later by a write operation, even on different object, the first read is said to be causally ordered before the write. …
On February 26th 2015 the first meeting of Germany’s Rhein/Neckar User group will take place in Heidelberg.
Georg Richter, lead of MariaDB’s connectors team will give a talk “Don’t! No! Never!- common mistakes in relational database systems”.
Two special guests (Sanja Byelin, MariaDB Server Core Developer and Lawrin Novitsky, lead developer of MariaDB’s Connector/ODBC) will be available too for answering your questions and discussing/collecting your ideas around MariaDB, Percona, MySQL related and other database management systems.
Celebrate free speech, but also free beer (sponsored by MariaDB Corporation) and join on us on Feb. 26th in Heidelberg! …
Continue reading “MariaDB Rhein/Neckar Usergroup meeting in Heidelberg/Germany”
MariaDB Galera server logs all the cluster related information like node status, cluster status, membership, etc. in the error log. MariaDB 10.1.2 introduces a new INFORMATION SCHEMA plugin WSREP_INFO that enables querying these information via INFORMATION SCHEMA tables. The WSREP_INFO plugin adds two new tables to the Information Schema, WSREP_MEMBERSHIP and WSREP_STATUS. The plugin is not enabled by default, so in order to use it, it needs to be installed first :
MariaDB [test]> INSTALL SONAME ‘wsrep_status’;
Query OK, 0 rows affected (0.04 sec)
MariaDB [test]> SHOW PLUGINS;
+—————————–+———-+——————–+—————–+———+
| Name | Status | Type | Library | License |
+—————————–+———-+——————–+—————–+———+
… …
Continue reading “MariaDB 10.1.2 : INFORMATION_SCHEMA tables for Galera membership & status”
MariaDB 10.1 server is now “Galera ready” with the latest 10.1.1 release. It includes wsrep (write set replication) patch that enables server to load the wsrep provider (galera) library and interact with it to provide multi-master synchronous replication support. The patch implements hooks inside server and storage engines to populate and apply the write sets on sender and receiver nodes in a cluster respectively. The wsrep patch also adds a number of system and status variables (prefixed with wsrep) that can be used to configure and monitor the server acting as a node in Galera cluster.
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Sometimes users ask for something that doesn’t really make sense. On the first glance. But then you start asking and realize that the user was right, you were wrong, and it is, actually, a perfectly logical and valid use case.
I’ve had one of these moments when I’ve heard about a request of making triggers to work on the slave in the row-based replication. Like, really? In RBR all changes made by triggers are replicated from the master to slaves as row events. If triggers would be fired on the slave they would do their changes twice. And anyway, assuming that one only has triggers one the slave (why?) in statement-based replication triggers would run on the slave normally, wouldn’t they? …