Sql – Efficient SQL test query or validation query that will work across all (or most) databases

C3PO and DBCP development have stalled mostly because they are mature. I have seen both of these drivers be able to support hundreds of transactions per second.

The Tomcat pool is a reworked & updated DBCP driver. MyBatis 3.0 also contains it's own pooling implementation which, based on code inspection, seems solid. Finally, there's BoneCP which claims to have the best performance. I haven't used any of these on a project yet.

Probably the best advice is to pick any of them test it. Spring makes it easy to swap out later.

Oh great, so the question in the thread you mention was actually asked by me a long ago :) It'd be interesting to see how to use that in your use case.

But let me tell you Hive launches Hadoop jobs whenever required depending upon you query. So, if you want to execute multiple queries, which I believe is what you want to do here, you need to use a job scheduler that can run multiple jobs concurrently. Hadoop by default uses first-in-first-out(FIFO) scheduler, pulling jobs from a work queue. So, would like to switch to Fair scheduler or Capacity scheduler.

The core idea behind the fair share scheduler was to assign resources to jobs such that on average over time, each job gets an equal share of the available resources.

The capacity scheduler shares some of the principles of the fair scheduler but has distinct differences, too. First, capacity scheduling was defined for large clusters, which may have multiple, independent consumers and target applications.In capacity scheduling, instead of pools, several queues are created, each with a configurable number of map and reduce slots. Each queue is also assigned a guaranteed capacity (where the overall capacity of the cluster is the sum of each queue's capacity). Second, ability to prioritize jobs within a queue. Lastly, is the presence of strict access controls on queues.