I have a table in Oracle db with a lot of inserts and updates. All these changes ends up in the archive log and makes the performance slow. How do I turn off archive logging for a table?
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We are building a system in our company which will need temporal tables in sql server and might need log shipping as well. I wanted to know if there are any unexpected impacts of log shipping on a temporal table that wouldn't happen on a normal table?
I would expect no impact in either direction (that is, log song won't change the temporal table nor will the temporal table change log shipping). At its core, log shipping is just restoring transaction logs on another server. And temporal tables are (more or less) a trigger that maintains another table on data mutations. That extra work will be present in the log backup and will restore just fine at the log shipping secondary
Previously in the company we used temporary tables, but when the volume of business data had to grow, we had to change the queries using WITH
WITH table_alias AS (SELECT ...)
I need some light here. I am working with SQL Server 2008.
I have a database for my application. Each table has a trigger to stores all changes on another database (on the same server) on one unique table 'tbSysMasterLog'. Yes the log of the application its stored on another database.
Problem is, before any Insert/update/delete command on the application database, a transaction its started, and therefore, the table of the log database is locked until the transaction is committed or rolled back. So anyone else who tries to write in any another table of the application will be locked.
So...is there any way possible to disable transactions on a particular database or on a particular table?
You cannot turn off the log. Everything gets logged. You can set to "Simple" which will limit the amount of data saved after the records are committed.
" the table of the log database is locked": why that?
Normally you log changes by inserting records. The insert of records should not lock the complete table, normally there should not be any contention in insertion.
If you do more than inserts, perhaps you should consider changing that. Perhaps you should look at the indices defined on log, perhaps you can avoid some of them.
It sounds from the question that you have a create transaction at the start of your triggers, and that you are logging to the other database prior to the commit transaction.
Normally you do not need to have explicit transactions in SQL server.
If you do need explicit transactions. You could put the data to be logged into variables. Commit the transaction and then insert it into your log table.
Normally inserts are fast and can happen in parallel with out locking. There are certain things like identity columns that require order, but this is very lightweight structure they can be avoided by generating guids so inserts are non blocking, but for something like your log table a primary key identity column would give you a clear sequence that is probably helpful in working out the order.
Obviously if you log after the transaction, this may not be in the same order as the transactions occurred due to the different times that transactions take to commit.
We normally log into individual tables with a similar name to the master table e.g. FooHistory or AuditFoo
There are other options a very lightweight method is to use a trace, this is what is used for performance tuning and will give you a copy of every statement run on the database (including triggers), and you can log this to a different database server. It is a good idea to log to different server if you are doing a trace on a heavily used servers since the volume of data is massive if you are doing a trace across say 1,000 simultaneous sessions.
https://learn.microsoft.com/en-us/sql/tools/sql-server-profiler/save-trace-results-to-a-table-sql-server-profiler?view=sql-server-ver15
You can also trace to a file and then load it into a table, ( better performance), and script up starting stopping and loading traces.
The load on the server that is getting the trace log is minimal and I have never had a locking problem on the server receiving the trace, so I am pretty sure that you are doing something to cause the locks.
Usually auditing is done through triggers, however I have created temporal tables for my database, so that I can do data forensics as well auditing. I also have an auditing requirement, that is , if I were to restore my database to an earlier state, the audit data( history table) needs to be kept intact and only the original table needs to be restored. The history tables remain same regardless the restoration point.
One way that i can achieve this is turning off the system versioning off and then restore the original tables and again turn the system versioning on. This seems really hectic task to to for every tables since I got about 500-1000 tables that i need to audit.
One more query, If temporal tables aren't good for auditing ,should I go for traditional Triggers for data auditing then?
In PostgreSQl 9.1, the streaming replication is done by streaming WALs records which is generated by UPDATEs and DELETEs on the Master’s data.
How are the DDL changes replicated? Those are not the part of WALs.
Postgresql's Write Ahead Log (WAL) does contain DDL. In Postgresql, DDL is transactional, just like DML. All goes through the WAL.
See http://wiki.postgresql.org/wiki/Transactional_DDL_in_PostgreSQL:_A_Competitive_Analysis
To elaborate on Colin's answer, almost everything goes through the write-ahead log. It is a block level journal that records every write that will be made to any database structure. Every change to any part of the data directory is first recorded in the WAL. That's because the primary purpose of the WAL is to allow replay of changes if the system crashes or loses power, so it needs to record every single planned disk write.
In PostgreSQL, tables, views, etc are just entries in the system catalog tables. Changes to these catalogs get write-ahead logged along with everything else. The same is true of database creation; a db is just an entry in pg_database and the corresponding directory structure.
Changes to tables made by VACUUM, CLUSTER, TRUNCATE etc; they all go through WAL, either with block-level change records or special WAL entries to describe the operation.
Only a few non-durable things don't go through WAL, like:
changes to UNLOGGED and TEMPORARY tables
Temp files for on-disk sorts
How can I record all the Inserts and Updates being performed on a database (MS SQL Server 2005 and above)?
Basically I want a table in which I can record all the inserts andupdates issues on my database.
Triggers will be tough to manage because there are 100s of tables and growing.
Thanks
Bullish
We have hundreds of tables and growing and use triggers. In newer versions of SQL server you can use change Data Capture or Change Tracking but we have not found them adequate for auditing.
What we have is are two separate audit tables for each table (one for recording the details of the instance (1 row even if you updated a million records) and one for recording the actual old and new values), but each has the same structure and is created by running a dynamic SQL proc that looks for unauditied tables and creates the audit triggers. This proc is run every time we deploy.
Then you should also take the time to write a proc to pull the data back out of the audit tables if you want to restore the old values. This can be tricky to write on the fly with this structure, so it is best to have it handy before you have the CEO peering down your neck while you restore the 50,000 users accidentally deleted.
As of SQL Server 2008 and above you have change data capture.
Triggers, although unwieldy and a maintenance nightmare, will do the job on versions prior to 2008.