Nr 280084 add support for postgre sql v17

[rahulreddy15]

Postgres 17 introduced a new table pg_stat_checkpointer
Metrics originally being collected from pg_stat_bgwriter were moved to pg_stat_checkpointer
Queries were modified to collect the metrics from the new table.
Two metrics buffers_backend and buffers_backend_fsync were dropped in Postgres 17. (https://pgpedia.info/p/pg_stat_bgwriter.html) and are no longer available.

The schema and inventory JSONs for the integration tests were modified to reflect the new metric names and modified inventory variables.

Instance definitions were version dependent. A new way to manage version dependence was created in order to future proof.

[sigilioso]

Two metrics buffers_backend and buffers_backend_fsync were dropped in Postgres 17. (https://pgpedia.info/p/pg_stat_bgwriter.html) and are no longer available.

From the commit removing the corresponding metrics:

These are actually not checkpointer properties but backend properties.
Also, pg_stat_io provides a more accurate and equivalent report of these
numbers, by tracking all the I/O stats related to backends, including
writes and fsyncs, so storing them in pg_stat_checkpointer was
redundant.

I wonder if we could find some equivalent values in the pg_stat_io table and avoid a breaking change.

[sigilioso]

Thank you for taking care of this and great job so far!

I'd check if we can get the missing metrics and when that's ready we can sync to update the changelog and prepare the release. In the meantime, find some comments/suggestions below (merely nits).

[rahulreddy15]

Added a query to get buffers_backend buffers_backend_fsync from pg_stat_io.

All metrics that were reported before postgres v17 are also reported for postgres v17.

Note : Metrics variable names are changed to reflect the table they come from. So:
bgwriter.buffersWrittenForCheckpointsPerSecond -> checkpointer.buffersWrittenForCheckpointsPerSecond
bgwriter.checkpointSyncTimeInMillisecondsPerSecond -> checkpointer.checkpointSyncTimeInMillisecondsPerSecond
bgwriter.checkpointWriteTimeInMillisecondsPerSecond -> checkpointer.checkpointWriteTimeInMillisecondsPerSecond
bgwriter.checkpointsRequestedPerSecond -> checkpointer.checkpointsRequestedPerSecond
bgwriter.checkpointsScheduledPerSecond -> checkpointer.checkpointsScheduledPerSecond
bgwriter.backendFsyncCallsPerSecond -> io.backendFsyncCallsPerSecond
bgwriter.buffersWrittenByBackendPerSecond -> io.buffersWrittenByBackendPerSecond

[sigilioso]

Note : Metrics variable names are changed to reflect the table they come from.

The metrics names change matches the changes in the latest version of PostgreSQL which makes perfect sense. However it is also a breaking change since anything relying on the previous names will stop working for PostgreSQL 17. We can either:

• Carry on with the breaking changes and notify/document properly.
• Keep the previous naming and also update the corresponding docs to make the metric source very clear.

[sigilioso]

The changes LGTM, well done!

There are two small things to take care of:

• I've left a nit comment regarding the new test.
• We need to update the CHANGELOG in order that the pre-release and release are automaticall triggered. You'll find more information regarding the changelog in the release-toolkit and coreint-automation repositories. There are also examples in previous PRs. Ping me if you need more context 🙂

[sigilioso]

LGTM 🚀