Zhenglong Li

This PR looks good to me, but since I'm not so familiar with the DSM, so it's better to have another to review it again. And I simple updated the...

Reproduced this BUG by opening the GUC of `gp_enable_global_deadlock_detector`: ``` gpconfig -c gp_enable_global_deadlock_detector -v on nohup pgbench -U smart postgres -n -T 30 -c 32 -j 2 -f test_transaction.sql >...

The RCA of this problem is mentioned by the PR https://github.com/greenplum-db/gpdb/pull/9452, but that PR only returns `waitGxids` after the prepare stage. However, we should return the `waitGxids` every DML statement...

Maybe some refactoring should be done to the function `connect()` :thinking:

@Cito Hi~ Do we have a plan to refactor the function of `connect()` in pgdb.py? Since the semantics and parameter settings of this function are weird and ambiguous. For example,...