Correlated Tracing of Requests through TDS
A trace header with an activity identifier is sent between a client and a database server as part of a request message stream. The activity identifier gets logged by client-side connection-related traces, by server-side traces, and by database engine traces. The activity identifier can be used to exactly correlate a thread on the client to threads on the server. Additionally, specific threads within a database engine may be correlated using the activity identifier to track the threads that processed a particular request. This enhances troubleshooting of the database system, particularly when there are many concurrent users and threads.
1 . A computer-implemented method, comprising:
generating a request by a thread on a client machine, the request comprising data to be sent to a database server using packets configured using a Tabular Data Stream (TDS) protocol;
inserting a trace header into the request, the trace header comprising an activity identifier that is unique to the request, the activity identifier comprising a randomly generated globally unique identifier (GUID) associated with the thread on the client machine plus a sequence number associated with the request generated by the thread, wherein a new sequence number is assigned to each request sent by the thread; and
transmitting the request to the database server.
2 . The computer-implemented method of claim 1 , further comprising:
logging the request in one or more layers of a stack using a tracing operation.
3 . The computer-implemented method of claim 1 , further comprising:
logging the request in a client driver stack layer;
logging the request in a TDS protocol stack layer; and
logging the request in a database server stack layer.
4 . The computer-implemented method of claim 3 , further comprising:
correlating the logged requests in the client driver stack layer, the TDS protocol stack layer, and the database server stack layer using the activity identifier.
5 . The computer-implemented method of claim 1 , further comprising:
receiving the request at the database server; and
associating the activity identifier with one or more threads running on the database server.
6 . The computer-implemented method of claim 5 , further comprising:
correlating two or more of the threads running on the database that were used to process the request containing the activity identifier.
7 . The computer-implemented method of claim 1 , wherein the request is a SQL batch or Remote Procedure Call (RPC) request.
8 . The computer-implemented method of claim 1 , wherein the GUID a sixteen-byte number and the sequence number is a four-byte number.
9 . The computer-implemented method of claim 1 , further comprising:
generating a response on database server, the response comprising data to be sent to the client machine using packets configured using the TDS protocol;
inserting a trace header into the response, the trace header comprising the activity identifier; and
transmitting the response to the client machine.
10 . A computer system, comprising:
one or more processors;
system memory;
one or more computer-readable storage media having stored thereon computer-executable instructions that, when executed by the one or more processors, causes the processors to perform a method for tracing requests in a database system, the processor operating to:
generate a request by a thread, the request comprising data to be sent to a database server using packets configured using a Tabular Data Stream (TDS) protocol;
insert a trace header into the request, the trace header comprising a activity identifier that is unique to the request, the activity identifier comprising a randomly generated globally unique identifier (GUID) associated with the thread on the client machine plus a sequence number associated with the request generated by the thread, wherein a new sequence number is assigned to each request sent by the thread; and
transmit the request to the database server.
11 . The computer system of claim 10 , the processor further operating to:
log the request in one or more layers of a stack using a tracing operation.
12 . The computer system of claim 10 , the processor further operating to:
log the request in a client driver stack layer;
log the request in a TDS protocol stack layer; and
log the request in a database server stack layer.
13 . The computer system of claim 10 , the processor further operating to:
correlate the logged requests in the client driver stack layer, the TDS protocol stack layer, and the database server stack layer using the activity identifier.
14 . The computer system of claim 10 , wherein the request is a SQL batch or Remote Procedure Call (RPC) request.
15 . The computer system of claim 10 , wherein the GUID a sixteen-byte number and the sequence number is a four-byte number.
16 . A computer-implemented method, comprising:
receiving a request by a thread on a database server, the request comprising data packets configured using a Tabular Data Stream (TDS) protocol;
identifying a trace header in the request, the trace header comprising an activity identifier that is unique to the request, the activity identifier comprising a randomly generated globally unique identifier (GUID) associated with the thread on the client machine plus a sequence number associated with the request generated by the thread, wherein a new sequence number is assigned to each request sent by the thread; and
associating the activity identifier with one or more threads running on the database server.
17 . The computer-implemented method of claim 16 , further comprising:
correlating two or more of the threads running on the database that were used to process the request containing the activity identifier.
18 . The computer-implemented method of claim 16 , further comprising:
generating a response on database server, the response comprising data to be sent to a client machine using packets configured using the TDS protocol;
inserting a trace header into the response, the trace header comprising the activity identifier; and
transmitting the response to the client machine.
19 . The computer-implemented method of claim 16 , wherein the request is a SQL batch or Remote Procedure Call (RPC) request.
20 . The computer-implemented method of claim 16 , wherein the GUID a sixteen-byte number and the sequence number is a four-byte number.