This bug uncovered serious issues with how the data was being stored by PSGM.
So it require a complete redesign.
pg_stat_monitor now stores the data locally within the backend process's local
memory. The data is only stored when the query completes. This reduces the
number of lock acquisitions that were previously needed during various stages
of the execution. Also, this avoids data loss in case the current bucket
changes during execution. Also, the unavailability of jumble state during later
stages of executions was causing pg_stat_monitor to save non-normalized query.
This was a major problem as well.
pg_stat_monitor specific memory context is implemented. It is used for saving
data locally. The context memory callback helps us clear the locally saved data
so that we do not store it multiple times in the shared hash.
As part of this major rewrite, pgss reference in function and variable names
is changed to pgsm. Memory footprint for the entries is reduced, data types
are corrected where needed, and we've removed unused variables, functions and
macros.
This patch was mutually created by:
Co-authored-by: Hamid Akhtar <hamid.akhtar@percona.com>
Co-authored-by: Muhammad Usama <muhammad.usama@percona.com>
Added buckets for queries that take less than minimum histogram time
and one for the ones taking more than the max value specified.
Also, in case the buckets end up overlapping, on server start, an
error will be thrown informing the user of this issue and requesting
a rectification.
Refactored the code to consolidate the calculations in a single
function.
PG-456: Running pgindent to make source indentation/spacing PostgreSQLCompatible.
PostgreSQL uses pgindent from time to time to make source code PostgreSQL
style guide compatible, it is a very long time since we have not done that.
Commit fixes a lot of indentation and spacing issues.
Co-authored-by: Hamid Akhtar <hamid.akhtar@gmail.com>
pg_stat_monitor.pgsm_normalized_query needs to be 0 by default because
people will get Query examples. This is one of the main user-faced
advantages of pgsm over pgss (pg_stat_statements).
There was no maximum limit set for the number of maximum histograms
bucket, which can lead to a crash in case of higher value.
PG-382: Adjust the maximum value for histogram buckets.
Fix the regression issue related to GUC and set the maximum
buckets value correctly.
PG-382: Adjust the maximum value for histogram buckets.
Fix the TAP test cases.
There was no maximum limit set for the number of maximum histograms
bucket, which can lead to a crash in case of higher value.
PG-382: Adjust the maximum value for histogram buckets.
Fix the regression issue for PostgreSQL-12.
PG-382: Adjust the maximum value for histogram buckets.
Fix the TAP test cases.
Changed the default value of pgsm_bucket_time from 300 to 60. Now neither PMM users will need to adjust the default value, nor
restart of PG server will be required for this purpose.
Hamid Akhtar
Ibrar Ahmed
Ibrar Ahmed
Ibrar Ahmed
Francisco Miguel Biete
Diego Fronza
Naeem Akhter