title: Spring JPA with Hikari not releasing connection
body: <p>I have a spring boot application which has a controller. When I try to hit an API simultaneously (35 parrallel hits) it comes to the controller but there I am using findOne of the crudrepository which checks postgres for some data.
  The findOne functions returns in milliseconds but the next API doesn't get hold of postgres connection.</p>
  
  <p>I am using HikariCp as the connection pooler with following settings</p>
  
  <pre><code>hikari:
   idleTimeout: 10000
   connectionTimeout: 60000
   maximumPoolSize: 30
   minimumIdle: 2
   poolName: gor-srms
   leakDetectionThreshold: 10000
  </code></pre>
  
  <p>In short at any point of time only 30 API's are working in parallel. Once the API is finished then only next one gets postgres connection.</p>
  
  <p>Why is postgres connection not getting used for other API's since the findOne call only takes about millisecs to complete?</p>
  
  <p>Adding the complete application properties:</p>
  
  <pre><code>server:
     port: ${SERVER_PORT:${PORT:8093}}
     contextPath: ${mdm.service.contextPath:/wms-masterdata}
  
  spring:
    application:
      name: ${mdm.service.name:mdm-service}
    jmx:
      enabled: false
    profiles:
      active: local
    cloud:
      config:
        discovery:
          enabled: false
          serviceId: config-server
    jpa:
        hibernate:
          ddl-auto: validate
    http:
        multipart:
          max-file-size: 20MB
          max-request-size: 20MB
  
  discovery:
    enabled: true
  
  eureka:
    client:
      enabled: ${discovery.enabled:true}
      serviceUrl:
        defaultZone: ${discovery.url:${REGISTRY_SERVICE_URL:http://localhost:8761}}/eureka/
    instance:
      metadataMap:
        contextPath: ${server.contextPath}
  
  db:
    driver: org.postgresql.Driver
    url: jdbc:postgresql://${database.ip:localhost}:5432/wms_masterdata
    username: postgres
    password: postgres
  
  hikari:
    idleTimeout: 10000
    connectionTimeout: 60000
    maximumPoolSize: 10
    minimumIdle: 2
    poolName: gor-mdm
    leakDetectionThreshold: 60000
  
  hibernate:
    unit_name: wms_masterdata
    show_sql: false
    generate_ddl: false
  
  entitymanager:
    packagesToScan: com.gor.platform.mdm.service.model
  
  butler:
    url: https://192.168.8.116
  
  management:
    security:
      enabled: false
    health:
      db:
        enabled: false
  
  security:
    basic:
      enabled: false
  
  flyway:
    baseline-on-migrate: true
    enabled: true
    ignore-ignored-migrations: true
  </code></pre>