Logged Merge Phases in IQMSG File

The server logs RLV merge activity in the database IQMSG file.

The five phases of the merge are logged with a line suffixed by Mrg.

Log Suffix	Merge Phase
Mrg B <table_id> <merge_type> [merge_host]	Begin
Mrg D	Delete
Mrg U	Update
Mrg I	Insert
Mrg E	End

For the merge Begin phase, <merge_type> is one of:

D – automatic DDL blocking merge

M – automatic DML blocking merge

N – non-blocking merge

[merge_host] is an optional connection handle for an internal connection used to run the merge. This occurs if you execute a DDL merge. The connection running the DDL will use another internal server connection to run the merge. When the merge completes, the connection calling the DDL connection resumes.

An example IQMSG entry for a merge is:

I. 01/20 17:25:27. 0000000022 Txn 179 0 179
I. 01/20 17:25:27. 0000000021 Mrg  B 775 D 0000000017
I. 01/20 17:26:28. 0000000021 Mrg D
I. 01/20 17:26:29.  0000000021 Mrg U
I. 01/20 17:26:34. 0000000021 Mrg I
I. 01/20 17:26:39.  0000000021 Mrg E
I. 01/20 17:26:39. 0000000021 Cmt 188

The prefix to each line is a timestamp and the connection ID logging the request. In this case, connection 21 is an internal connection running the merge. In the first line, Txn 179 0 179 is the standard message denoting a begin transaction with ID 179. The third line shows that a merge has begun against table ID 775, that it is a DDL blocking merge and that the connection that launched the merge is 17. The last line shows that connection 21 commits, and the commit ID is 188.