Now it's time to release something useful! At least I hope so. I have been going through how I came up with this idea and how I came up with the implementation in a series of blog posts:
But now it's time for the real deal, the software itself. This is an Alpha 1.0 release but it should work OK in the more basic setups. It's available for download from sourceforge, and here you find the source package which uses GNU autotools to build. The manual is part of this download, but is also available as a separately.
You do need MariaDB libraries and includefiles to build it, but no Oracle specific libraries are needed, only Oracle itself of course. There are build instructions in the documentation.
Cheers and happy replication folks
/Karlsson
Thursday, October 2, 2014
Wednesday, October 1, 2014
Replication from Oracle to MariaDB the simple way - Part 4
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:
This looks more complex than it is, actually, all that is needed is some smart PL/SQL and this will work. I have not done much of any kind of testing, except checking that the basics work, but the PL/SQL needed I have done for you, and the order table triggers and what have you not is also created for you by a shell script that can do this for any table.
As for the DUMMY table that I have to use to get a trigger on COMMIT, this doesn't have to have that many rows, I actually just INSERT into it once per transaction, and then I INSERT the transaction id, which I get from Oracle. This table will have some junk in it after a while, all the transactions that were started and COMMITted will have an entry here. But in my code for this, I have included a simple job that purges this table from inactive transactions.
Best of all is that this works even with Oracle Express, so no need to pay for "Advanced Replication", not that I consider it really advanced or anything. I'd really like to know what you think about these ideas? Would it work? I know it's not perfect, far from it, for for the intent of having a MariaDB table reasonable well syncronized with an Oracle, this should work. Or? The solution is on one hand simple and lightweight, but I have given up on the number of features and possibly also the design affects performance a bit.But it should be good enough for many uses I think?
Let me hear what you think, I'm just about to release this puppy!
/Karlsson
As for the DUMMY table that I have to use to get a trigger on COMMIT, this doesn't have to have that many rows, I actually just INSERT into it once per transaction, and then I INSERT the transaction id, which I get from Oracle. This table will have some junk in it after a while, all the transactions that were started and COMMITted will have an entry here. But in my code for this, I have included a simple job that purges this table from inactive transactions.
Best of all is that this works even with Oracle Express, so no need to pay for "Advanced Replication", not that I consider it really advanced or anything. I'd really like to know what you think about these ideas? Would it work? I know it's not perfect, far from it, for for the intent of having a MariaDB table reasonable well syncronized with an Oracle, this should work. Or? The solution is on one hand simple and lightweight, but I have given up on the number of features and possibly also the design affects performance a bit.But it should be good enough for many uses I think?
Let me hear what you think, I'm just about to release this puppy!
/Karlsson
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