Re: CREATE INDEX CONCURRENTLY does not index prepared xact's data

> 19 июля 2021 г., в 05:30, Noah Misch <noah@leadboat.com> написал(а):
>
> To fix $SUBJECT, it sounds like we need a way to identify a transaction,
> usable as early as the transaction's first catalog access and remaining valid
> until COMMIT PREPARED finishes.  We may initially see a transaction as having
> a VXID and no XID, then later need to wait for that transaction when it has
> entered prepared state, having an XID and no VXID.  How might we achieve that?

PFA draft with vxid->xid mapping and subsequent wait for it. The patch, obviously, lacks a ton of comments explaining
whatis going on. 
We write actual VXID into dummy proc entries of prepared xact.
When we wait for vxid we try to convert it to xid through real proc entry. If we cannot do so - we lookup in shared 2pc
state.If vxid is not there - it means it is already gone and there's nothing to wait. 

Thanks!

Best regards, Andrey Borodin.