Why is My First Go `database/sql` Query So Much Slower Than Subsequent Queries?

Why is querying using database/sql much slower than querying the database directly?

When using database/sql in Go, the initial query can be significantly slower than subsequent queries. This is because a new connection to the database is established for the first query. To mitigate this, it's recommended to use the Ping method on the database connection pool to establish a connection before executing the first query.

Reason for the Discrepancy

The database/sql package manages a pool of connections, rather than a single connection. When the Query method is called for the first time, it obtains a connection from the pool and executes the query. However, if the pool is empty, a new connection must be established, which can take some time. Subsequent queries reuse the existing connection, making them faster.

Solution

To avoid this initial delay, the Ping method can be used to establish a connection before the first query. This ensures that a connection is available for the first query, reducing the overall execution time.

Additional Notes

• Prepared statements, which involve separate values from the SQL query string, can also introduce additional overhead. However, using prepared statements is still typically more efficient than using positional parameters embedded in the query string.
• The specific performance characteristics may vary depending on the underlying database driver and the network latency between the client and the database.

The above is the detailed content of Why is My First Go `database/sql` Query So Much Slower Than Subsequent Queries?. For more information, please follow other related articles on the PHP Chinese website!