Fix a problem in explicitly PREPARED TRANSACTIONS.

Problem:
  If a transaction contains read only statements,
  it gets started on data nodes but is never ended
  in case of a PREPARE TRANSACTION 'my_gxid'.
  Even if we do not need to prepare it on the
  data nodes we still need to end it.

Solution:
  The function pgxc_node_remote_prepare()
  has been modified to send PREPARE TRANSACTION on nodes
  where this transaction is doing some write, and
  COMMIT TRANSACTION to nodes where it did some read only
  activity.

Test cases are added to make sure the prepared transactions
are working as expected.

0 files changed, 0 insertions, 0 deletions