Thread-safe singleton version of groovy.sql.Sql

ThreadSafeSql.groovy

import groovy.sql.Sql
import javax.sql.DataSource

class ThreadSafeSql extends Sql implements GroovyInterceptable   {
    private final ThreadLocal<Sql> threadLocal = new ThreadLocal<>()
    private final DataSource dataSource

    ThreadSafeSql(DataSource dataSource) {
        super(dataSource)
        this.dataSource = dataSource
    }

    def invokeMethod(String name, Object args) {
        def sql = threadLocal.get()
        if (!sql) {
            sql = new Sql(dataSource)
            threadLocal.set(sql)
        }
        sql.invokeMethod(name, args)
    }
}

Instantiate ThreadSafeSql only once and then use it in any thread of your application thread pools - you'll get the profit of thread local in full! Since this is a subclass of groovy.sql.Sql you don't need to change much.