Support Min connection pool parameter #3009

[htrajan]

My attempt to address #3009

Hopefully this is sensible with the tests I've included

I suspect that lack of this functionality is causing my company's app to frequently hit bottlenecks with allocating new db pool connections

[chasdevs]

LGTM; I'm not a maintainer of this library, though 😅

[brianc]

nice tests. this looks good to me, tbh! I prefer my pools to drain when my app is idle...feels better to me than leaving a bunch of sockets open doing nothing for > 5 minutes, but I can definitely see in some "needs to be fast, but gets spikey traffic" this could come in handy. That initial connection to the backend is no joke. I've seen it take upwards of a second on GCS in the past.

[htrajan]

nice tests. this looks good to me, tbh! I prefer my pools to drain when my app is idle...feels better to me than leaving a bunch of sockets open doing nothing for > 5 minutes, but I can definitely see in some "needs to be fast, but gets spikey traffic" this could come in handy. That initial connection to the backend is no joke. I've seen it take upwards of a second on GCS in the past.

Great! What would be the next steps to get this into the next release?

[charmander]

Thoughts on implementing or documenting:

• prefilling the pool to the minimum
• maintaining the minimum on connection errors

?

Keepalives are also sort of related to this, but I think any documentation and work needed there stands on its own.