Repocopy databases/pgpool-II-40 and modify it to introduce
new pgpool version 4.1.x.
Major enhancements in Pgpool-II 4.1 include:
* Statement level load balancing.
* Auto failback.
* Enhance performance in number of areas.
* Shared relation cache allows to reuse relation cache among sessions to reduce internal queries against PostgreSQL system catalogs.
* Have separate SQL parser for DML statements to eliminate unnecessary parsing effort.
* Load balancing control for specific queries.
* Reduce Internal Queries against System Catalogs.
* Import PostgreSQL 12 SQL parser.
PR: 244646
Submitted by: Franko Ricci <franco.ricc@gmail.com>