On 25/02/2020 09:13, Fujii Masao wrote: > Hi, > > I'm thinking to change the progress reporting views like > pg_stat_progress_vacuum so that they also report the time when > the target command was started and the time when the phase was > last changed. IMO this is very helpful to estimate the remaining > time required to complete the current phase. For example, > if pg_stat_progress_vacuum reports that the current phase > "scanning heap" started 1 hour before and the progress percentage > is 50%, we can imagine the remaining time of this phase would be > approximately 1 hour. Of course, this is not the exact estimation, > but would be helpful as a hint for operations. Thought? > > ProgressCommandType st_progress_command; > Oid st_progress_command_target; > int64 st_progress_param[PGSTAT_NUM_PROGRESS_PARAM]; > > We cannnot add those timestamp fields simply in the progress > reporting views because the type of the fields in PgBackendStatus > struct is only int64 for now, as the above. So I'm thinking to add > new TimestampTz fields (maybe four fields are enough even for > future usager?) into PgBackendStatus and make pg_stat_get_progress_info() > report those fields as timestamp. This change leads to increase > in the size of PgBackendStatus, as demerit. But I like this approach > because it's simple and intuitive. > > Another idea is to store TimestampTz values in int64 fields > (for example, always store TimestampTz values in the last two int64 > fields) and make pg_stat_get_progress_info() report not only int64 > but also those TimestampTz fields. This approach doesn't increase > the struct size, but is a bit tricky. Also int64 fields that TimestampTz > values will be stored into might be already used to store int64 values > in some existing extensions. If we need to handle this case, further > tricky way might need to be implemented. That sounds not good. > > Therefore, I'd like to implement the first idea that I described, to > add the timestamp fields in the progress reporting view. Thought?
+1 on the idea. No opinion on the implementation. -- Vik Fearing
