Re: POC: Extension for adding distributed tracing - pg_tracing

Hi,

On Thu, 12 Oct 2023 at 14:32, Anthonin Bonnefoy
<anthonin(dot)bonnefoy(at)datadoghq(dot)com> wrote:
>
> Hi!
>
> I've made a new batch of changes and improvements.
> New features:
> - Triggers are now correctly supported. They were not correctly
> attached to the ExecutorFinish Span before.
> - Additional configuration: exporting parameter values in span
> metadata can be disabled. Deparsing can also be disabled now.
> - Dbid and userid are now exported in span's metadata
> - New Notify channel and threshold parameters. This channel will
> receive a notification when the span buffer usage crosses the
> threshold.
> - Explicit transaction with extended protocol is now correctly
> handled. This is done by keeping 2 different trace contexts, one for
> parser/planner trace context at the root level and the other for
> nested queries and executors. The spans now correctly show the parse
> of the next statement happening before the ExecutorEnd of the previous
> statement (see screenshot).
>
> Changes:
> - Parse span is now outside of the top span. When multiple statements
> are processed, they are parsed together so it didn't make sense to
> attach Parse to a specific statement.
> - Deparse info is now exported in its own column. This will leave the
> possibility to the trace forwarder to either use it as metadata or put
> it in the span name.
> - Renaming: Spans now have a span_type (Select, Executor, Parser...)
> and a span_operation (ExecutorRun, Select $1...)
> - For spans created without propagated trace context, the same traceid
> will be used for statements within the same transaction.
> - pg_tracing_consume_spans and pg_tracing_peek_spans are now
> restricted to users with pg_read_all_stats role
> - In instrument.h, instr->firsttime is only set if timer was requested
>
> The code should be more stable from now on. Most of the features I had
> planned are implemented.
> I've also started writing the module's documentation. It's still a bit
> bare but I will be working on completing this.

In CFbot, I see that build is failing for this patch (link:
https://cirrus-ci.com/task/5378223450619904?logs=build#L1532) with
following error:
[07:58:05.037] In file included from ../src/include/executor/instrument.h:16,
[07:58:05.037] from ../src/include/jit/jit.h:14,
[07:58:05.037] from ../contrib/pg_tracing/span.h:16,
[07:58:05.037] from ../contrib/pg_tracing/pg_tracing_explain.h:4,
[07:58:05.037] from ../contrib/pg_tracing/pg_tracing.c:43:
[07:58:05.037] ../contrib/pg_tracing/pg_tracing.c: In function
‘add_node_counters’:
[07:58:05.037] ../contrib/pg_tracing/pg_tracing.c:2330:70: error:
‘BufferUsage’ has no member named ‘blk_read_time’; did you mean
‘temp_blk_read_time’?
[07:58:05.037] 2330 | blk_read_time =
INSTR_TIME_GET_MILLISEC(node_counters->buffer_usage.blk_read_time);
[07:58:05.037] | ^~~~~~~~~~~~~
[07:58:05.037] ../src/include/portability/instr_time.h:126:12: note:
in definition of macro ‘INSTR_TIME_GET_NANOSEC’
[07:58:05.037] 126 | ((int64) (t).ticks)
[07:58:05.037] | ^
[07:58:05.037] ../contrib/pg_tracing/pg_tracing.c:2330:18: note: in
expansion of macro ‘INSTR_TIME_GET_MILLISEC’
[07:58:05.037] 2330 | blk_read_time =
INSTR_TIME_GET_MILLISEC(node_counters->buffer_usage.blk_read_time);
[07:58:05.037] | ^~~~~~~~~~~~~~~~~~~~~~~
[07:58:05.037] ../contrib/pg_tracing/pg_tracing.c:2331:71: error:
‘BufferUsage’ has no member named ‘blk_write_time’; did you mean
‘temp_blk_write_time’?
[07:58:05.037] 2331 | blk_write_time =
INSTR_TIME_GET_MILLISEC(node_counters->buffer_usage.blk_write_time);
[07:58:05.037] | ^~~~~~~~~~~~~~
[07:58:05.037] ../src/include/portability/instr_time.h:126:12: note:
in definition of macro ‘INSTR_TIME_GET_NANOSEC’
[07:58:05.037] 126 | ((int64) (t).ticks)
[07:58:05.037] | ^
[07:58:05.037] ../contrib/pg_tracing/pg_tracing.c:2331:19: note: in
expansion of macro ‘INSTR_TIME_GET_MILLISEC’
[07:58:05.037] 2331 | blk_write_time =
INSTR_TIME_GET_MILLISEC(node_counters->buffer_usage.blk_write_time);
[07:58:05.037] | ^~~~~~~~~~~~~~~~~~~~~~~

I also tried to build this patch locally and the build is failing with
the same error.

Thanks
Shlok Kumar Kyal