feat(server): introduce maxResultSize limit and fix pg errors handling

[avallete]

What kind of change does this PR introduce?

• Fixes the way we handled pg.Pool non "database" error (connection level errors) to avoid throwing unhandled exception, but instead make sure it get caught and propagated to the caller in the response via poolerQueryHandleError
• Going along with feat: add maxResultSize limit node-postgres#1 introducing a way to cap the maximum size we allow a query to take in memory before aborting with an error.

With those changes the running server should be more robust, die less often and leverage killing the connections sooner than later.

Fixes PGMETA-45

[avallete]

This will need more testing on staging, and will need close monitoring on prod deploy. But should help reduce the spikes of 5xx errors we see.

[avallete]

note

With the new error propagation, had to slightly tweak this as the instanceof wasn't properly working. Even tough the constructor was the right one, the instance kept being an Error because of the promise wrapping.

[coveralls]

Pull Request Test Coverage Report for Build 14112748589

Details

• 61 of 65 (93.85%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.5%) to 75.947%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/server/constants.ts	4	5	80.0%
src/lib/db.ts	53	56	94.64%

Totals
Change from base Build 13958195217:	0.5%
Covered Lines:	4991
Relevant Lines:	6490

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💛 - Coveralls

[linear]

PGMETA-45 Fork node-postgres and handle errors