\db- List all tablespaces
\dn- List all schemas
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If you have a problem with PostgreSQL, it starts some processes that consume lots of resources. You kill those processes but they will restart after a few minutes.
Later you check the /var/log but there is nothing about this. What does that mean?😟
What is High Availability?
It is the amount of time that a service is available and is usually defined by the business.
A recent scenario,
We had a single table with about 50M records that use around 80gb of space. Application recently deleted older records which was no longer needed reducing the Number of records to 30M.
Sometimes RMAN backup files might get corrupted. Sometimes disk block corruption might happen. So it is better we do validate the database backups more frequently in order to make sure it is recoverable.
I had gone through Oracle documents, forums, and other websites but could not get a clear picture of what blocksize to choose for my environment where 64 bit OLTP databases are running. I came across the following websites that give practical and more useful information about Oracle Block size selection.
http://www.ixora.com.au/tips/buffered_block_size.htm
http://www.nextre.it/oracledocs/blocksize.html
This is a great explanation of Postgres toast internals for anyone who doesn't know about them
https://hakibenita.com/sql-medium-text-performance
By enabling and disabling the following parameters, we can influence the query execution plan generated by the optimizer.
If you have followed the instructions to make a replica (If not have a visit at this quick post), and your replication setup is not working, than the first thing to do is check MySQL error log. (if you dont know where it is? Just check my.cnf for the location of that file). Most of time, you will get the actual error from the log if not than you can try below things.
Recently, when I tried to increase the memory_target of Oracle database, I got the following error:
ORA-00845: MEMORY_TARGET not supported on this system
While checking, we found that /dev/shm size was 2 GB, but we were trying to increase the memory_target values to 7 GB that is more than the size of /dev/shm. So we got the error.
Then we increased the /dev/shm size to 8 GB using the command as below
mount -t tmpfs shmfs -o size=8192m /dev/shm
After that, we were able to bring up the database with the parameter value memory_target =7G without the issue.
After my recent DB upgrade activity, I was unable to create extension and was failing with the below errors.
There are various ways to know since how long PostgreSQL is running.
Below will cover 3 ways to find this.