Re: Add index scan progress to pg_stat_progress_vacuum

>    At the beginning of a parallel operation, we allocate a chunk of>
>    dynamic shared memory which persists even after some or all workers
>    have exited. It's only torn down at the end of the parallel operation.
>    That seems like the appropriate place to be storing any kind of data
>    that needs to be propagated between parallel workers. The current
>    patch uses the main shared memory segment, which seems unacceptable to
>    me.

Correct, DSM does track shared data. However only participating
processes in the parallel vacuum can attach and lookup this data.

The purpose of the main shared memory is to allow a process that
Is querying the progress views to retrieve the information.

Regards,

Sami Imseih
Amazon Web Services