Horton

Log a sample of transactions

Adrien Nayrat <adrien.nayrat@anayrat.info>

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From: Adrien Nayrat <adrien.nayrat@anayrat.info>
To: PostgreSQL mailing lists <pgsql-hackers@postgresql.org>
Cc: Nikolay Samokhvalov <samokhvalov@gmail.com>
Date: 2018-12-12T21:32:06Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Tweak docs for log_statement_sample_rate

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Hello,

Per idea of Nikolay Samokhvalov[1] I propose this patch to add the possibility
to log all statements from a fraction of transactions.

I have several questions:
  * Do we want this feature?
  * How can I add tests? I seems hard to handle tests when a there is duration
in the output.
  * Should I handle the case when someone try to change the setting *inside* a
transaction:

# SET client_min_messages to LOG;
SET
# SET log_transaction_sample_rate to 1;
SET
# BEGIN;
LOG:  duration: 0.364 ms  statement: BEGIN;
BEGIN
# SELECT 1;
LOG:  duration: 0.530 ms  statement: SELECT 1;
-[ RECORD 1 ]
?column? | 1

# SET log_transaction_sample_rate to 0;
LOG:  duration: 0.333 ms  statement: SET log_transaction_sample_rate to 0;
SET
# SELECT 1;
LOG:  duration: 0.586 ms  statement: SELECT 1;
-[ RECORD 1 ]
?column? | 1

Thanks

[1]:
https://www.postgresql.org/message-id/CANNMO%2BLg65EFqHb%2BZYbMLKyE2y498HJzsdFrMnW1dQ6AFJ3Mpw%40mail.gmail.com


-- 
Adrien NAYRAT