[Feature request] tracing in SQL requests

[mingmxu]

Feature request

Is your feature request related to a problem? Please describe.
It's hard to dig into the details while troubleshooting a query. In our use case, queries from clients are sent to Starrocks using the JDBC protocol, and Datadog is the observability platform for log/metric collection, etc.

It lacks some core features when looking into the details of the query processing:

• there's no trace for SQL queries to show the processing steps, communication between FE/BE, etc;
• not able to find all the log events based on query_id;

Describe the solution you'd like
With OpenTelemetry, we build a platform-independent trace record for each SQL request to expose the processing information, including spans and log events, within/between FE and BE components. It includes several improvements:

• build trace record for each SQL request;
• support trace context propagation from client;
• support trace context from FE to BE;
• attach trace context to log events;

Describe alternatives you've considered

Additional context
We run a PoC(proof-of-concept) to achieve some of the requirements, the solution is implemented as below:

• trace context is added as a comment to the SQL;
• In FE, it starts a trace record for each query, with the parentContext extracted from SQL comments when provided;
• trace context is added to log events as tags with MDC, BE is not covered in the PoC;

[mingmxu]

cc @dengliu @chaoyli