Sunday, July 19, 2015

2015-07-19 Sunday - MySQL Federated Engine

I'm doing some research this weekend on MySQL's Federated Engine.  This posting is placeholder for collecting various information I find that might be of interest to others.

https://en.wikipedia.org/wiki/MySQL_Federated

http://dev.mysql.com/

http://dev.mysql.com/doc/refman/5.7/en/federated-storage-engine.html

https://dev.mysql.com/doc/refman/5.7/en/federated-usagenotes.html

  • FEDERATED table does not support indexes in the usual sense; because access to the table data is handled remotely, it is actually the remote table that makes use of indexes. This means that, for a query that cannot use any indexes and so requires a full table scan, the server fetches all rows from the remote table and filters them locally. This occurs regardless of any WHERE or LIMIT used with this SELECT statement; these clauses are applied locally to the returned rows
  • Queries that fail to use indexes can thus cause poor performance and network overload. In addition, since returned rows must be stored in memory, such a query can also lead to the local server swapping, or even hanging.

http://dba.stackexchange.com/questions/10850/any-disadvantages-to-enabling-federated-storage-engine

http://www.fromdual.com/federated-storage-engine

http://stackoverflow.com/questions/5210309/how-can-i-enable-federated-engine-in-mysql-after-installation

http://www.xaprb.com/blog/2007/01/29/mysqls-federated-storage-engine-part-1/
http://www.xaprb.com/blog/2007/01/31/mysqls-federated-storage-engine-part-2/

http://mihasya.com/blog/abusing-mysql-the-federated-engine/

https://blog.engineyard.com/2012/mysql-table-engines

  • "a number of limitations and due to network latency are rarely used...not enabled by default and is no longer maintained by Oracle and it's use is discouraged"

No comments: