Horton

Re: [PATCH] Identify LWLocks in tracepoints

Craig Ringer <craig.ringer@enterprisedb.com>

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From: Craig Ringer <craig.ringer@enterprisedb.com>
To: Andres Freund <andres@anarazel.de>
Cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-05-05T04:20:04Z
Lists: pgsql-hackers

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On Wed, 5 May 2021 at 09:15, Craig Ringer <craig.ringer@enterprisedb.com> wrote:

>> warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
>>  1322 |    TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode);
>>       |                                                          ^
>
> Odd that I didn't get that.

This compiler complaint is not due to the _ENABLED() test as such.
It's due to the fact that we completely define out the
TRACE_POSTGRESQL_ macros with src/backend/utils/Gen_dummy_probes.sed .

While explicit braces could be added around each test, I suggest
fixing Gen_dummy_probes.sed to emit the usual dummy statement instead.
Patch attached.

Commits

  1. Emit dummy statements for probes.d probes when disabled

  2. Prevent lwlock dtrace probes from unnecessary work

  3. doc: Fix typo in logicaldecoding.sgml.

  4. Move lwlock-release probe back where it belongs

  5. Remove bogus tracepoint

  6. Simplify LWLock tranche machinery by removing array_base/array_stride.

  7. Improve LWLock scalability.