Re: WIP Patch: Pgbench Serialization and deadlock errors

Hello again!

Here is the third version of the patch for pgbench thanks to Fabien
Coelho comments. As in the previous one, transactions with serialization
and deadlock failures are rolled back and retried until they end
successfully or their number of tries reaches maximum.

Differences from the previous version:
* Some code cleanup :) In particular, the Variables structure for
managing client variables and only one new tap tests file (as they were
recommended here [1] and here [2]).
* There's no error if the last transaction in the script is not
completed. But the transactions started in the previous scripts and/or
not ending in the current script, are not rolled back and retried after
the failure. Such script try is reported as failed because it contains a
failure that was not rolled back and retried.
* Usually the retries and/or failures are printed if they are not equal
to zeros. In transaction/aggregation logs the failures are always
printed and the retries are printed if max_tries is greater than 1. It
is done for the general format of the log during the execution of the
program.

Patch is attached. Any suggestions are welcome!

[1]
https://www.postgresql.org/message-id/alpine.DEB.2.20.1707121338090.12795%40lancre
[2]
https://www.postgresql.org/message-id/alpine.DEB.2.20.1707121142300.12795%40lancre

--
Marina Polyakova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company