How to solve “Socket read timed out” when using hikari connection pool

Question

I am developing an application using play framework (version 2.8.0), java(version 1.8) with an oracle database(version 12C).

There is only zero or one hit to the database in a day, I am getting below error.

java.sql.SQLRecoverableException: IO Error: Socket read timed out
    at oracle.jdbc.driver.T4CConnection.logoff(T4CConnection.java:919)
    at oracle.jdbc.driver.PhysicalConnection.close(PhysicalConnection.java:2005)
    at com.zaxxer.hikari.pool.PoolBase.quietlyCloseConnection(PoolBase.java:138)
    at com.zaxxer.hikari.pool.HikariPool.lambda$closeConnection$1(HikariPool.java:447)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.SocketTimeoutException: Socket read timed out
    at oracle.net.nt.TimeoutSocketChannel.read(TimeoutSocketChannel.java:174)
    at oracle.net.ns.NIOHeader.readHeaderBuffer(NIOHeader.java:82)
    at oracle.net.ns.NIOPacket.readFromSocketChannel(NIOPacket.java:139)
    at oracle.net.ns.NIOPacket.readFromSocketChannel(NIOPacket.java:101)
    at oracle.net.ns.NIONSDataChannel.readDataFromSocketChannel(NIONSDataChannel.java:80)
    at oracle.jdbc.driver.T4CMAREngineNIO.prepareForReading(T4CMAREngineNIO.java:98)
    at oracle.jdbc.driver.T4CMAREngineNIO.unmarshalUB1(T4CMAREngineNIO.java:534)
    at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:485)
    at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:252)
    at oracle.jdbc.driver.T4C7Ocommoncall.doOLOGOFF(T4C7Ocommoncall.java:62)
    at oracle.jdbc.driver.T4CConnection.logoff(T4CConnection.java:908)
    ... 6 common frames omitted

db {
default {
driver=oracle.jdbc.OracleDriver
url="jdbc:oracle:thin:@XXX.XXX.XXX.XX:XXXX/XXXXXXX"
username="XXXXXXXXX"
password="XXXXXXXXX"
hikaricp {
  dataSource {
    cachePrepStmts = true
    prepStmtCacheSize = 250
    prepStmtCacheSqlLimit = 2048
      }
     }
  }
}

It seems it is causing due to inactive database connection, How can I solve this? Please let me know if any other information is required?

Answer 1

You can enable TCP keepalive for JDBC - either be setting directive or by adding "ENABLE=BROKEN" into connection string.

• Usually Cisco/Juniper cuts off TCP connection when it is inactive for more that on hour.
• While Linux kernel starts sending keepalive probes after two hours(tcp_keepalive_time). So if you decide to turn tcp keepalive on, you will also need root, to change this kernel tunable to lower value(10-15 minutes)
• Moreover HikariCP should not keep open any connection for longer than 30 minutes - by default.

So if your FW, Linux kernel and HikariCP all use default settings, then this error should not occur in your system.

See HikariCP official documentation

maxLifetime: This property controls the maximum lifetime of a connection in the pool. An in-use connection will never be retired, only when it is closed will it then be removed. On a connection-by-connection basis, minor negative attenuation is applied to avoid mass-extinction in the pool. We strongly recommend setting this value, and it should be several seconds shorter than any database or infrastructure imposed connection time limit. A value of 0 indicates no maximum lifetime (infinite lifetime), subject of course to the idleTimeout setting. The minimum allowed value is 30000ms (30 seconds). Default: 1800000 (30 minutes)

Answer 2

I have added the below configuration for hickaricp in configuration file and it is working fine.

## Database Connection Pool

play.db.pool = hikaricp
play.db.prototype.hikaricp.connectionTimeout=120000
play.db.prototype.hikaricp.idleTimeout=15000
play.db.prototype.hikaricp.leakDetectionThreshold=120000
play.db.prototype.hikaricp.validationTimeout=10000
play.db.prototype.hikaricp.maxLifetime=120000