[DSIP-31] Reduce the connection pool size of hikari

[ruanwenjun]

Search before asking

• I had searched in the DSIP and found no similar DSIP.

Motivation

I am not clear why we set the hikari thread pool size, I don't find out any benchmark test result.

Following https://github.com/brettwooldridge/HikariCP/wiki/About-Pool-Sizing, I hope to remove some configurations of hikari, the default setting is great enough. We shouldn't change the default setting unless we have benchmark evidence.

dolphinscheduler/dolphinscheduler-api/src/main/resources/application.yaml

Lines 52 to 62 in e66441a

	hikari:
	connection-test-query: select 1
	minimum-idle: 5
	auto-commit: true
	validation-timeout: 3000
	pool-name: DolphinScheduler
	maximum-pool-size: 50
	connection-timeout: 30000
	idle-timeout: 600000
	leak-detection-threshold: 0
	initialization-fail-timeout: 1

Design Detail

Only keep the pool name and connection-test-query
hikari:
connection-test-query: select 1
pool-name: DolphinScheduler

Compatibility, Deprecation, and Migration Plan

Compatible with all version.

Test Plan

Test by e2e.

Code of Conduct

• I agree to follow this project's Code of Conduct