Is There a Truly Database-Agnostic SQL Connection Test Query?

Database-Agnostic Test Queries for SQL Connections

Database connection pooling libraries often include functionality for testing SQL connections for idleness. However, many recommended test queries, such as "SELECT 1;", are specific to certain databases and may fail with others.

Is there a truly database-agnostic test query?

Unfortunately, there is no single query that works across all SQL databases.

Database-Specific Queries

If you need a comprehensive approach, consider using multiple queries tailored to different database providers:

• MySQL, H2, PostgreSQL, SQLite, Hive: SELECT 1
• Oracle: SELECT 1 FROM DUAL
• HSQLDB: SELECT 1 FROM any_existing_table WHERE 1=0
  SELECT 1 FROM INFORMATION_SCHEMA.SYSTEM_USERS
  CALL NOW()
• Apache Derby: VALUES 1 or SELECT 1 FROM SYSIBM.SYSDUMMY1
• DB2: SELECT 1 FROM SYSIBM.SYSDUMMY1
• Informix: select count(*) from systables

Note:

• If using WHERE 1=0 in HSQLDB, ensure it returns rows for Apache Commons DBCP's validationQuery.
• Consider using programming techniques to determine and execute the appropriate query based on the database provider configuration.

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