Federated engine status?

[bugi]

How does the federated engine in Percona 5.7 compare to the one in MariaDB?

Federated in mariadb 5.5 works fine for my case, but I recall mysql 5.1’s federated crashing a lot. I’m preparing an upgrade to a more recent mysql, and whether we choose percona or mariadb hinges largely on this question.

[George_Lorch]

A quick git diff between PS 5.5 and 5.7 on ha_federated.cc shows very few changes (well, none that I could see) that are not directly related to changes to server code (performance schema, etc…). So I believe that unless MariaDB has done any work to the federated engine, it should be relatively the same across PS 5.5, 5.6, 5.7 and MariaDB 5.5 and 10.x.

[bugi]

Thank you for the response.

MariaDB uses the FederatedX engine when a user calls for Federated. That’s an effort by the authors of Federated to address shortcomings of that engine.
[LIST]
[]So this in mariadb: https://github.com/MariaDB/server/tree/10.1/storage/federatedx/
[]and this in percona: https://github.com/percona/percona-server/tree/5.7/storage/federated/
[*]and in percona’s 5.1 tree: https://github.com/percona/percona-server/tree/5.1/Percona-Server/storage/federated/
[/LIST] The federated engines used in mariadb and percona are much different, enough so that it seems pointless to compare their code.

One could simply compare the 5.1 code with the 5.7 code, but I’m not familiar enough with mysql code to judge it in any kind of detail. I do see it’s changed quite a bit (diffstat below). How much of that is 5.1->5.7 drift and how much is fixing the crashes and other misery that was in 5.1’s Federated?

$ diff -u ha_federated.cc-5.1 ha_federated.cc-5.7 |diffstat
ha_federated.cc-5.7 | 502 +++++++++++++++++++++++++++-------------------------
1 file changed, 268 insertions(+), 234 deletions(-)

Or, is there a list of bugs that’ve been addressed in Federated over the years?