TRFC internals - how does the async processing happen?

Question

tRFC internals - how does the async processing happen?
Dear all,
With the document "[https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/f078394a-4469-2910-c4bf-853c75674694|https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/f078394a-4469-2910-c4bf-853c75674694]" there is an excellent place to read about SAP RFCs (remote function calls).
Pages 94 to 96 describe in detail how tFRC (transactional RFC) works.
However, there is still something unclear for me with the following sentence on page 94:
"The truly exciting part happens when the program
issues a COMMIT WORK command. The recorded calls
are executed asynchronously in a special set of tRFC
processing sessions created for each transaction ID..."
Maybe someone can answer the following questions:
a) what does exactly trigger and execute the tRFC?
b) is it the ABAP runtime system itself, spawning the additional task in DIA?
c) if multiple tRFC LUWs have been recorded, they are all executed in parallel by this procedure!?
d) does the execution try to utilize all available DIA processes?
e) how do the rdisp/rfc_... parameter come into the game?
   are they evaluated? We have seen all DIA occupied by the tRFCs executed!
Best regards,
Peter
P.S.: if someone has answers to these ones, more related to error handling, would be great as well
f) the jobs ARFC*, do they also use parallel processing?
   or is every ARFC* job responsible only for one single LUW?
   (note https://service.sap.com/sap/support/notes/366807 did not give a perfect answer)
g) and how does the report RSARFCEX work compared to immediate execution?

Answer 1

That's the problem, it won't.
internal static string GetAvailabilityGroupFromConnection(SPDatabase db)
if (!UsesAvailabilityConnection(db))
return null;
string dataSource = db.ConnectionString.DataSource;
string cmdText = string.Format(CultureInfo.InvariantCulture, "\r\n SELECT name FROM sys.availability_groups g\r\n JOIN sys.availability_group_listeners l ON g.group_id = l.group_id\r\n WHERE dns_name = '{0}'\r\n ", new object[] { dataSource });
string str3 = null;
using (SqlCommand command = new SqlCommand(cmdText))
ULS.SendTraceTag(0x302263, ULSCat.msoulscat_WSS_Database, ULSTraceLevel.Medium, "Looking up availability group for listener: {0}", new object[] { cmdText });
using (SqlDataReader reader = GetSessionFromDatabase(db).ExecuteReader(command))
while (reader.Read())
str3 = reader.GetString(0);
ULS.SendTraceTag(0x302280, ULSCat.msoulscat_WSS_Database, ULSTraceLevel.Medium, "Found group {0} for listener {1}", new object[] { str3, dataSource });
This piece of code looks at the SPDatabase's connection string (the SQL alias, for example) and executes a T-SQL query looking for that name within SQL Server. Since the SQL alias does not exist within the SQL Server's configuration, it will return a null
value, and you won't be able to set up the AG config using the AG cmdlets.
Also, since mobility exists by the very nature of using an AG Listener, using a SQL Alias is redundant.
Trevor Seward
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This post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, its employees, or other MVPs.