Description James Sutherland 2009-04-01 10:55:32 EDT

By default we currently use,
- read pool with 2 connections
- write pool with 5-10 connections

This has the following issues
- 7 connections connected at startup adding to startup cost and useability
- only 2 read connections gives poor concurrency (can't scale past 2 threads)
- 5-10 write connections also give poor conurrency > 10 threads, and at > 5 threads start thrasing connections (connect/disconnect each access)
- the split read/write pools make for an in-efficient usage of connections, if you have 32 threads you need to allocate 32+32=64 connections instead of just 32 with a shared pool

Enhancement is to add:
- Support for initial size on ConnectionPool, this is number of connections used at startup (will then grow to min and wait at max)
- Use a shared (exclusive) read/write connection pool by default, use a single pool for the read and default write conneciton pool
- When add/reomving connections, always use the tail, not the head of the queue, this is more efficient, and gives better performance because it uses a "hot" connection