Is it possible to write a stored procedure or trigger that will be executed automatically inside of a database on particular time without any calls from application? If yes, then could anybody give me an example or link to some resource where I can read how to do that.
Check out pgAgent. If that doesn't work for you, there's always cron in Unix/Linux and the Task Scheduler service in Windows.
I don't think there's anything built-in, but you might want to check out
pgjobs or pgAgent.
You can use Stored Procedures. Stored Procedure is a set of statements, which allow ease and flexibility for a programmer because stored procedure is easy to execute than reissuing the number of individual SQL statements but they need to perform the same database operations.Using the stored procedure less information needs to be sent between the server and the client.
You can visit These links :-
Postgres Procedures
Best way to use stored Procedures
Related
I often have to execute complex sql scripts in a single transaction on a large PostgreSQL database and I would like to verify everything that was changed during the transaction.
Verifying each single entry on each table "by hand" would take ages.
Dumping the database before and after the script to plain sql and using diff on the dumps isn't really an option since each dump would be about 50G of data.
Is there a way to show all the data that was added, deleted or modified during a single transaction?
Dude, What are you looking for is the most searchable thing on the internet when it comes to capturing Database changes. It is a kind of version control we can say.
But as long as I know, sadly there are no in-built approaches are available in PostgreSQL or MySql. But you can overcome it by setting/adding some triggers for your most usable operations.
You can create some backup schemas, and tables to capture your changes that are changed(updated), created, or deleted.
In this way you can achieve what you want. I know this process is fully manual, But really effective.
If you need to analyze the script's behaviour only sporadically, then the easiest approach would be to change server configuration parameter log_min_duration_statement to 0 and then back to any value it had before the analysis. Then all of the script activity will be written to the instance log.
This approach is not suitable if your storage is not prepared to accommodate this amount of data, or for systems in which you don't want sensitive client data to be written to a plain-text log file.
I need to implement transparent encryption in Postgres (TDE). To do this, I found which functions are called when INSERT and SELECT are triggered. Used LLVM-LLDB on SELECT.
I'm trying to do the same with INSERT - does not work
the base process stops and does not allow insertion. I did everything about one manual https://eax.me/lldb/.
What could be wrong? how to find out which functions are called upon insertion (in the case of SELECT, this is secure_read, etc.)? And, if anyone knows how to change the function code in the source?
First, the client and server are located on the same machine, the same user adds data and reads them
Unfortunately I do not have enough reputation to add a screenshots.
The SQL statements are the wrong level to start debugging. You should look at the code where blocks are read and written. That would be in src/backend/storage/smgr.
Look at the functions mdread and mdwrite in md.c. This is probably where you'd start hacking.
PostgreSQL v12 has introduced “pluggable storage”, so you can write your own storage manager. See the documentation. If you don't want to patch PostgreSQL, but have an extension that will work with standard PostgreSQL, that would be the direction to take.
So far I have only covered block storage, but you must not forget WAL. Encrypting that will require hacking PostgreSQL.
This is a complex question which you should post to PostgreSQL hackers distribution list https://www.postgresql.org/list/pgsql-hackers/.
You could start by setting a GDB breakpoint in Executor_Start in execMain.c
We're doing Windows development against a DB2 database with QMF v9.1. We hard-code many of our SQL queries directly into our applications, even though they are already stored in QMF.
However, I was told that a built-in stored procedure exists that is able to return results from a QMF query or procedure. But the person could not tell me the name of the stored procedure.
Would anyone be able to share their experience in regards to the above? Many thanks in advance.
I think what you're looking for is Q.DSQQMFSP. The QMF Stored Proc interface has to be enabled, so it's not a "default" option.
Once that's done, it should be like calling any other stored proc from .NET
Similar to SQL script to create insert script, I need to generate a list of INSERT from a table to load onto another database (sqlite), like the dump command. I do this for sync purposes.
I have limitations because this will run on a cloud server without acces to the filesystem, so I need to do this in the DB (I can do this in the app server, I'm asking if is possible to do this in the DB directly).
In the app server, I load a datatable, walk his fieldnames and datatypes and build a insert... I wonder if exist a way to do the same in the DB...
I am not entirely sure whether that helps, but you can use simple ETL tool like 'Pentaho Kettle'. I used it once for a similar function and it did not take me more than 10 min. You can also schedule the jobs. I am not sure whether it is supported in database level.
Thanks,
Shankar
I'm working with an ETL tool, Business Objects Data Services, which has the capability of specifying parallel execution of functions. The documentation says that before you can do this, you have to make sure that your database, which in our case is Postgres, allows "a stored procedure to run in parallel". Can anyone tell me if Postgres does that?
Sure. Just run your queries in different connections, and they will run in parallel transactions. Beware of locking though.
You can also call different stored procedures from the same connection (and effectively still run them in parallel) by using DBLink.
See this SO answer to see an example.