CODEWITHSUNDEEP
javaconnection-poolingapache-commons-dbcp
bugs_
bugs_

Reputation: 3724

DBCP - validationQuery for different Databases

I use DBCP pool and I want use testOnBorrow and testOnReturn to test if connection is still valid.
Unfortunately I have to set property validationQuery to make it work.

Question: What value should be in validationQuery?

I know, that: validationQuery must be an SQL SELECT statement, that returns at least one row.

Problem is that we use various databases (DB2, Oracle, hsqldb).

Upvotes: 90

Views: 75484

Answers (4)

bugs_
bugs_

Reputation: 3724

There is not only one validationQuery for all databases. On each database you have to use different validationQuery.

After few hours of googling and testing I have collected this table:

Database validationQuery notes

  • hsqldb - select 1 from INFORMATION_SCHEMA.SYSTEM_USERS
  • Oracle - select 1 from dual
  • DB2 - select 1 from sysibm.sysdummy1
  • mysql - /* ping */ select 1
  • microsoft SQL Server - select 1 (tested on SQL-Server 9.0, 10.5 [2008])
  • postgresql - select 1
  • ingres - select 1
  • derby - values 1
  • H2 - select 1
  • Firebird - select 1 from rdb$database
  • MariaDb - select 1
  • Informix - select 1 from systables
  • Hive - select 1
  • Impala - select 1

I wrote about it on my blog - validation query for various databases.

In advance there is an example of class, which return validationQuery according to JDBC driver.

Or does anybody have better solution?

Upvotes: 230

Amit P
Amit P

Reputation: 544

For MairaDB validation query is "select 1" .

Upvotes: 1

yossis
yossis

Reputation: 1273

For MySQL with the Connector/J driver, there's a lightweight validation query that just sends a ping to the server and returns a dummy result set. The validation query can be (or should start with) exactly the following string:

/* ping */

For more infor refer to the Validating Connections in the MySQL driver manual

Upvotes: 15

Deepan Prabhu Babu
Deepan Prabhu Babu

Reputation: 912

For Informix, The validation query is, select 1 from systables

Upvotes: 4

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