Loopback not utilizing connection pool fully

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Using loopback datasources for postgres, we provided max connection pool of 20. As soon as app starts it makes two connection. When doing load test using jmeter, it is seen that only those two are being used. But after some time new connection were formed, to match the max number. But in any given second active connection were never more than 3. Also it was like utilizing a stack of connections because it is noticed that the last released connection was used. So, system was never able to use near 10-15 connections although they were there in idle state. This resulted in a tps of 160, for a process which comprised :

http in -> two db insert -> http out
The model had 200 fields, there are minimum validations, with no hooks, beforeSave, afterSave etc.

Attaching connection logs:

Start: \ => represents http in
Stop: \ => represents http out

DB-Write Start: \\ => represents beginning of write process, handing it off to loopback
DB-Write Stop: \\ => represents end of write process,

\#\#\# 2021-07-01T13:26:39.589Z Acquired \ => represents acquiring process by pg, got using pg.pool.on('aquire',...)
releasing connection\#\#\# \ => releasing of said connection back to pool
\#\#\# 2021-07-01T13:26:40.148Z Connect \ => Making new connections

Thanks.
[connect_findings.txt](https://github.com/strongloop/loopback-next/files/6755393/connect_findings.txt)

No se nombran archivos fuente ni pruebas. Comienza con la configuración del pool de la datasource de PostgreSQL y los registros de conexión adjuntos; después, reproduce el patrón de carga de JMeter informado. Se considera terminado cuando se haya establecido por qué las conexiones inactivas del pool no se utilizan de forma concurrente y se haya documentado o corregido el comportamiento para que la utilización coincida con el pool configurado.

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