I'm facing a new challenge here.
I can't seem to find precedence for replication from MySQL, running on a Linux box to MS SQL Server.
Has anybody done this before?
Most importantly all changes made to the MySQL database should be replicated on the MS database realtime or close. MS database are not likely to be updated in any other way, so a bidirectional facility is not required.
I thought one way is to read the changes out of the binary log.
Has anyone parsed one before?
Thanks for your help guys.
Triggers in MySQL could be used to catch changes and call a UDF, which could then execute ODBC queries to MSSQL. Likely terrible for performance, though.
If immediate replication isn't required:
Write triggers in MySQL that capture insert, update, and delete statements in a log table.
Poll the log table from MSSQL using ODBC and execute them, then delete those log entries.
Of course, T-SQL and MySQL's variant of SQL isn't exactly the same, but it should be close for trivial CUD operations.
Check to see if DBSync will help you do what you want
I had similar task, but I had to replicate from MSSQL 2008 to Mysql in real time.
I tried this application http://enterprise.replicator.daffodilsw.com/ and it worked but it didn't look reliable. But you can check I may be wrong.
Finally I decided to use interface OLE DB and postgress instead instead of Mysql. It works properly.
Related
I am investigating a legacy app that uses an Oracle 8i database in a test environment, specifically trying to find out what tables are accessed for read, insert, update or delete when the user performs an app function.
What is the best/easiest way to do this? Can I simply get a list of all sql statements sent to the database? Can I see when stored procedures are called?
Having little experience with Oracle but getting help from a DBA, I'm thinking I should either use a trace or look at the redo log with LogMiner, but how?
Thanks!
What you could do is to harvest the sql's from v$sql. If the SQL's are properly written - using bind variables - you should be able to catch most of the statements in a table for this. I currently have no running v8 at hand but this should be possible.
In order to get most of them, you probably need to repeat the harvesting during the various workloads that run on the database.
I'm currently running Microsoft SQL Express Server.
When one user performs a query without committing it, it locks the entire table.
The problem is that malicious users might "ruin" the database by doing so on purpose.
How can I prevent this from happening?
You need to understand database isolation levels http://en.wikipedia.org/wiki/Isolation_(database_systems). Most likely you are running queries as seralizable which will have that effect. Try submitting some code.
I have a database with a rather large number of tables, about 3500, and an application that needs to access a table list.
On a particular server this takes over 2.5 min to return.
EXEC sp_tables #table_type="'TABLE'"
I know there are faster ways to do that but sadly I'm not in a position to modify the application and need to find a way to push it below 30 seconds so the application doesn't throw timeout errors.
So. What, if anything, can I do to improve the performance of this sp within sql server?
I have seen these stored procedures run slow if you do not have the GRANT VIEW DEFINITION permission set on your user account. From what I read, this will cause a security check to occur slowing down the query.
Maybe a SQL guru can comment on why, if this does help your problem.
Well, sp_tables is system code and can't be changed (could workaround in SQL Server 2000, not SQL Server 2005+)
Your options are
Change the SQL
Change command timeout
Bigger server
You've already said "no" to the obvious solutions...
You need to approach this just like any other performance problem. Why is it slow? Namely, where does it block? Disk IO? CPU? Network? Lock contention? The scientific method is to use a methodology like Waits and Queues, or its newer SQL 2008 equivalent Troubleshooting Performance Problems in SQL Server 2008. The lazy way is to simply check the wait_type, wait_time and wait_resource columns in sys.dm_exec_requests for the session executing the sp_tables call. Once you find out what is blocking the execution, you can proceed accordingly.
If I'd venture a guess, you'll discover contention as the cause: other sessions are locking table's metadata exclusively and thus block the execution of sp_tables, which has to wait until all operations in front of it finish.
I was asked in the interview tell me the different ways of exporting database from one sql server to another, I knew only about creating a .bak file and then restoring it to another sql server which I told them. However, they asked me about a single SQL INSERT command which will perform this task.
I have googled it and can not find it. Please tell me if there is any such command ?
I have never heard of such a command and this is the MS support article that tells you how to move database between servers. It gives three options none of which are a single insert statement, the closest is using sp_detach_db and sp_attach_db.
Well with a SQL Statement you can do a backup and a restore. Doing it with one SQL INSERT... I've never heard something like this. Maybe one table. But not the whole database.
The other way would be to use the "Copy Database Wizzard".
I am doing also interviews and sometimes you just ask stuff that does not exist or does not work and see what is happening.
If you had a linked server already, I would guess you could use sp_msforeachtable around an INSERT INTO server2.tbl SELECT * FROM tbl.
But that's not going to handle referential integrity order dependencies or scenarios where you might need IDENTITY INSERT, disabling triggers or whatever. Handling trivial cases is usually, by definition, trivial.
you need to say linked server
http://www.databasejournal.com/features/mssql/article.php/3085211/Linked-Servers-on-MS-SQL-Part-1.htm
http://www.databasejournal.com/features/mssql/article.php/3691721/Setting-up-a-Linked-Server-for-a-Remote-SQL-Server-Instance.htm
Are there any good database schema comparison tools out there that support Sybase SQL Anywhere version 10? I've seen a litany of them for SQL Server, a few for MySQL and Oracle, but nothing that supports SQL Anywhere correctly.
I tried using DB Solo, but it turned all my non-unique indexes into unique ones, and I didn't see any options to change that.
If you are willing to download SQL Anywhere Version 11, and Compare It!, check out the comparison technique shown here:
http://sqlanywhere.blogspot.com/2008/08/comparing-database-schemas.html
You don't have to upgrade your SQL Anywhere Version 10 database.
The new kid on the block is Qwerybuilder. It supports SQL Server, Sybase ASE, Sybase SQL Anywhere and Oracle. I've used it successfully with SQL Anywhere to track schema changes.
Two I've come across that support SQL Anywhere:
Upscene Database Workbench - http://www.upscene.com/products.dbw.sqlanywhere.php
Aquafold - http://www.aquafold.com/index-sybaseany.html
Each one appears has a schema comparison tool, however I have not used either to compare schemas.
SQLDelta is awesome. It is for SQL Server. I've used it with SQL 2000 and 2005. It will compare stored procedures, tables, views, permissions, indexes, etc. It can also compare data between tables I believe. You can sync the changes or generate SQL Scripts for later use. I use it often to script out db changes in development to production.
Ah...missed the Sybase remark. Not sure if SQLDelta can talk to it..but I'd probably give it a shot since Sybase is similar.
Try erwin (CA AllFusion ERwin Data Modeler). It supports quite a lot of different DBs, including SQL Anywhere, and is quite good in reverse/forward engineering and schema comparison. However, you may find it a bit too complex to use for the comparison...
I use SQL Data Compare from Red Gate along with SQL Compare the data compare allows you to Compare the contents of two databases and Automatically synchronize your data.
SQL compare allows you to do the same but with the database tables. Nice GUI on each and very easy setup. they also work on a remote database.
There not cheap but each has a 30 trail so you can get a feel if you like it or not.
Sybase PowerDesigner can also Compare or Merge your Database Schema.
It can also Load the Schema from various Databases by ODBC if you have Schema generation Scripts you can also load them into a Model.
Its an expensive tool but great to document and develop you schema changes IMHO.
Breck Carter's idea is a good one. For quick scans, I have an old product that is called DBDelta. I have it installed on an old Windows 2000 machine because the install I have will not work on an XP machine. It's a very small app that compares two SQL Anywhere databases across an ODBC connection.
I've done some searches to try and find a later copy, but have not been able to. The developer was Charles Butcher. I think he supported it for a while and then stopped back in 2002 or so.
I'll continue to look for a link. If I find something I will post it here.
QweryBuilder 5.5.0 will allow you to compare all procedures, functions, views, tables and triggers in one shot. This release is scheduled for mid May, 2010.
It hasn't been finalized yet but we are also looking at adding an option to turn the diff results into a script that can be executed on a target database.