Short patch to expose a function GetCurrentTransactionWALVolume() that gives the total number of bytes written to WAL by current transaction.
* It's simple and good feature. It is useful for system management, and forecasting
server spec(especially disk volume) on the system needed.
* Overhead is nothing unless my test.
* Compile and unit tests are no problem.
User interface to this information discussed on separate thread, so that we don't check the baby out with the bathwater when people discuss UI pros and cons.
Did you get good opinion in other thread?
I'd like to use seeing WAL volume sql and init value of WAL volume sql.
Your patch seems to init the value when start up the server now.
If we have init function, we can see database activities in each hours in a day from WAL volumes.
Now, we only see number of transactions and database volumes.
I'd like to see more detail activities from WAL volume in each minutes or hours.
It might be good for performance improvement by hackers, too
