This patch makes the tracing framework follow the general idea of Google's
Dapper paper: traces generated in a context of the same query are forming
a single-rooted acyclic tree where in a ScyllaDB case vertexes are spans running
on each involved replica Node and edges are RPCs sent from one Node to another.
- Each vertex in the tree above has an ID - "span ID".
- In order to be able to build the tree from the sessions traces we need
to know the parent "span ID" - the ID of a span that sent an RPC that created
the current span.
- Each span of a tracing session is given a 64-bit random span ID.
- The root span has a span_id::illegal_id value.
This patch adds:
- The described above parent span ID and a span ID to the one_session_records
object.
- The current span ID is passed in the trace_info struct to the remote replica.
- Add parent_id and span_id columns to system_traces.events table for the parent
ID and span ID.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
This script validates schemas of distributed system keyspaces:
system_traces and system_auth.
It tries to add the missing columns and checks that the existing columns
have expected types.
In case of any problem the corresponding info message is printed and non-zero exit
status is returned.
Extra columns are ignored.
The validation function may also be called from another Python program.
It returns True in case of success and False otherwise.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Message-Id: <1490195645-29905-1-git-send-email-vladz@scylladb.com>
