enabled query cache for ndb
    modified engine interface somewhat
sql/ha_innodb.h
    enabled query cache for ndb
    modified engine interface somewhat
sql/ha_ndbcluster.cc
    enabled query cache for ndb
    modified engine interface somewhat
    ndb will only allow caching and retrieval if running autocommit
      - return false, but do not invalidate
    commit count is used as engine data, i.e.
      - store commit count before store of cache
      - allow retrieval if commit count has not changed on a table
      - invalidate if commit count has changed
sql/ha_ndbcluster.h
    enabled query cache for ndb
    modified engine interface somewhat
sql/handler.cc
    enabled query cache for ndb
    modified engine interface somewhat
sql/handler.h
    enabled query cache for ndb
    modified engine interface somewhat
    new virtual handler method cached_table_registration called on each table before alowing store in query cache
      - return TRUE - ok to cache, FALSE - not allowed to cache, invalidate queries if engine_data below has changed
      - sets ulonglong (engine_data) that is stored in query cache for each table
      - sets callback to be called for each table before usage of cached query, callback = 0 -> no check later
sql/mysql_priv.h
    enabled query cache for ndb
    modified engine interface somewhat
    callcack prototype for callback to engine before query cache retrieval
sql/sql_cache.cc
    enabled query cache for ndb
    modified engine interface somewhat
    if callback is set on table in cache, do callback to check if allowed to use cache
    if not allowed to use cache, check if engine_data has changed, if so, invalidate all queries with that table
    + changes to store and pass callback and engine_data around
sql/sql_cache.h
    enabled query cache for ndb
    modified engine interface somewhat
    changes to store callback and engine_data
sql/table.h
    enabled query cache for ndb
    modified engine interface somewhat
    changes to store callback and engine_data


sql/ha_innodb.cc:
  enabled query cache for ndb
  modified engine interface somewhat
sql/ha_innodb.h:
  enabled query cache for ndb
  modified engine interface somewhat
sql/ha_ndbcluster.cc:
  enabled query cache for ndb
  modified engine interface somewhat
  ndb will only allow caching and retrieval if running autocommit
    - return false, but do not invalidate
  commit count is used as engine data, i.e.
    - store commit count before store of cache
    - allow retrieval if commit count has not changed on a table
    - invalidate if commit count has changed
sql/ha_ndbcluster.h:
  enabled query cache for ndb
  modified engine interface somewhat
sql/handler.cc:
  enabled query cache for ndb
  modified engine interface somewhat
sql/handler.h:
  enabled query cache for ndb
  modified engine interface somewhat
  new virtual handler method cached_table_registration called on each table before alowing store in query cache
    - return TRUE - ok to cache, FALSE - not allowed to cache, invalidate queries if engine_data below has changed
    - sets ulonglong (engine_data) that is stored in query cache for each table
    - sets callback to be called for each table before usage of cached query, callback = 0 -> no check later
sql/mysql_priv.h:
  enabled query cache for ndb
  modified engine interface somewhat
  callcack prototype for callback to engine before query cache retrieval
sql/sql_cache.cc:
  enabled query cache for ndb
  modified engine interface somewhat
  if callback is set on table in cache, do callback to check if allowed to use cache
  if not allowed to use cache, check if engine_data has changed, if so, invalidate all queries with that table
  + changes to store and pass callback and engine_data around
sql/sql_cache.h:
  enabled query cache for ndb
  modified engine interface somewhat
  changes to store callback and engine_data
sql/table.h:
  enabled query cache for ndb
  modified engine interface somewhat
  changes to store callback and engine_data