Can someone help me understand pg_locks? There are three fields related
to virtual and real xids:
virtualtransaction | text |transactionid | xid |virtualxid | text |
Our docs say 'virtualtransaction' is:
Virtual ID of the transaction that is holding or awaiting this lock
This field was clear to me.
and 'transactionid' is documented as:
ID of a transaction, or null if the object is not a transaction ID
In my testing it was the (non-virtual) xid of the lock holder. Is that
correct? Can it be a waiter?
'virtualxid' is documented as:
Virtual ID of a transaction, or null if the object is not a virtual transaction ID
In my testing this field is for locking your own vxid, meaning it owned
by its own vxid.
I looked at the C code in /pg/backend/utils/adt/lockfuncs.c and was
confused.
Clearly our documentation is lacking in this area and I would like to
clarify it.
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://enterprisedb.com
+ It's impossible for everything to be true. +
