There is a CDC enabled table of the following form:
create table dbo.foo ( id int not null primary key, a char(1), b char(1), c char(1), d char(1), e char(1), updated datetime not null default getdate(), active bit not null default 1);goWhen querying cdc.dbo_foo_CT, I see the paired records of the following form:
| __$start_lsn | __$end_lsn | __$seqval | __$operation | __$update_mask | id | a | b | c | d | e | updated | active | __$command_id |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0x02 | NULL | 0x01 | 1 | 0xFF | 1 | a | b | c | NULL | NULL | 12:00:00 | 1 | 1 |
| 0x02 | NULL | 0x01 | 2 | 0xFF | 1 | x | b | c | NULL | NULL | 13:00:00 | 1 | 2 |
Given operations 1 & 2 are delete & insert respectively, I might otherwise expect this to be a full-row delete-then-reinsert pattern from an app; but there are identical values in both__$start_lsn& __$seqval. When attempting to repro a delete/re-insert in a transaction, the __$seqval still increments AFAICT. Notably a merge command produces the delete/re-insert CDC pattern but still increments the __$seqval as expected.
CDC was only recently enabled, and every record in cdc.dbo_foo_CT is a paired record of this form although other CDC enabled tables in the same database do not show this pattern.
What could be causing this behavior?
