zhaorui

I would like to finish this PR if it is useful. But I know nothing about windows, so I can only finish the testings for Linux platform.

> I think testing only on Linux is fine, but this definitely needs a heavy rebase an the tests need to be changed to use the new Python based testing...

> > I would like to finish this PR if it is useful. But I know nothing about windows, so I can only finish the testings for Linux platform. >...

As there are very much differences between the current main branch and the code version of this PR, so I decide to make new changes based on the main branch...

> > As there are very much differences between the current main branch and the code version of this PR, so I decide to make new changes based on the...

> > I want to add a field named 'nsegs' to the distributed_forget log to represent the number of segments executing the distributed transaction. > > > A one-phase transaction...

> > And if this field could be included in some common xlog, that would be unified and simpler. > > One idea is to write `nseg` in the QE...

This PR is ready to be reviewed. Please continue reviewing. Thanks very much!