I developed a patch with a different approach - using custom statistics.
As in the previous approach, I store statistics separately in slots for
relations and for databases. It was also necessary to introduce a hook,
and all control is handled through an extension. Statistics collection
in the core occurs only if the hook is defined (i.e., the extension is
added to shared_preload_libraries).
The extension is also controlled by additional gucs that allow disabling
vacuum statistics collection, or collecting statistics only for system
relations, only for user relations, or only at the database or relation
level.
For now, I have divided them into several categories: general statistics
(including the number of removed tables and tuples, and how many times
wraparound prevention occurred), cost-based statistics, buffer
statistics, and timing statistics. Memory is dynamically freed or
allocated when the corresponding guc configuration changes. This
approach is still a work in progress.
In the README and documentation in the extension, I also added
information about how much memory will be used to store the objects
(approximately 300 KB) and added the function to measure memory
consumption.
Currently there are three patches:
The first patch still collects statistics about frozen pages and pages
where the visibility flag is cleared.
The second patch implements statistics collection in the core, but
without storing them.
The third patch is the extension itself, where the statistics are stored
and displayed, with the control mechanisms described above.
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Best regards,
Alena Rybakina
