- delegating methods left behind

- Also carry allow_concurrency value through to connection adapter
  (for postgresql)

- use new active support Module#synchronize
- allow_concurrency now switches between a null monitor and a
  regular monitor (defaulting to null monitor to avoid overhead)

- Distinguis meaning of "active_connections" to always mean connections
  associated with the current thread

So far so good, tests still run clean. Next steps: synchronize connection pool access
and modification, and change allow_concurrency to simply switch a real lock for a
null lock.

Signed-off-by: NJoshua Peek <josh@joshpeek.com>

This is already the default and adding it breaks SQL standards compatibility.

[#860 state:resolved]

Patch originally from http://dev.rubyonrails.org/ticket/5470

Signed-off-by: NPratik Naik <pratiknaik@gmail.com>

This reverts commit cd8e653d.

This reverts commit aee14630.

[#860 state:incomplete]

Signed-off-by: NMichael Koziarski <michael@koziarski.com>

Signed-off-by: NTarmo Tänav <tarmo@itech.ee>
Signed-off-by: NPratik Naik <pratiknaik@gmail.com>

[#861 state:resolved]

Signed-off-by: NJoshua Peek <josh@joshpeek.com>

Signed-off-by: NMichael Koziarski <michael@koziarski.com>

Signed-off-by: NMichael Koziarski <michael@koziarski.com>

This reverts commit 8b858782.

Move the transaction counter to the connection object rather than maintaining it on the current Thread.
Signed-off-by: NMichael Koziarski <michael@koziarski.com>
[#533 state:resolved]

[#622 state:resolved]

Also added change_column_null to both mysql and sqlite to keep the api features closer to postgresql.

[#617 state:resolved]

Fixed that create database statements would always include "DEFAULT NULL" (Nick Sieger) [#334 status:committed]