Re: Built-in connection pooler

Great, this latest patch applies cleanly to master.  installcheck world still passes.

> "connections_proxies" is used mostly to toggle connection pooling.
> Using more than 1 proxy is be needed only for huge workloads (hundreds 
> connections). 

My testing showed using only one proxy performing very poorly vs not using the pooler, even at 300 connections, with -3% TPS.  At lower numbers of connections it was much worse than other configurations I tried.  I just shared my full pgbench results [1], the "No Pool" and "# Proxies 2" data is what I used to generate the charts I previously shared.  The 1 proxy and 10 proxy data I had referred to but hadn't shared the results, sorry about that.

> And "session_pool_size" is core parameter  which determine efficiency of 

I will do more testing around this variable next.  It seems that increasing session_pool_size for connection_proxies = 1 might help and leaving it at its default was my problem.

> PgPRO EE version of connection pooler has "idle_pool_worker_timeout" 

Understood.

I attached a patch to apply after your latest patch [2] with my suggested changes to the docs.  I tried to make things read smoother without altering your meaning.  I don't think the connection pooler chapter fits in The SQL Language section, it seems more like Server Admin functionality so I moved it to follow the chapter on HA, load balancing and replication.  That made more sense to me looking at the overall ToC of the docs.

Thanks,

[1] https://docs.google.com/spreadsheets/d/11XFoR26eiPQETUIlLGY5idG3fzJKEhuAjuKp6RVECOU

[2] https://www.postgresql.org/message-id/attachment/102848/builtin_connection_proxy-11.patch