On Wed, Aug 7, 2024 at 10:12 AM Peter Smith <smithpb2...@gmail.com> wrote: > > This is mostly a repeat of my previous mail from a while ago [1] but > includes some corrections, answers, and more examples. I'm going to > try to persuade one last time because the current patch is becoming > stable, so I wanted to revisit this syntax proposal before it gets too > late to change anything. > > If there is some problem with the proposed idea please let me know > because I can see only the advantages and no disadvantages of doing it > this way. > > ~~~ > > The current patchset offers two forms of subscription refresh: > 1. ALTER SUBSCRIPTION name REFRESH PUBLICATION [ WITH ( refresh_option > [= value] [, ... ] ) ] > 2. ALTER SUBSCRIPTION name REFRESH PUBLICATION SEQUENCES > > Since 'copy_data' is the only supported refresh_option, really it is more > like: > 1. ALTER SUBSCRIPTION name REFRESH PUBLICATION [ WITH ( copy_data [= > true|false] ) ] > 2. ALTER SUBSCRIPTION name REFRESH PUBLICATION SEQUENCES > > ~~~ > > I proposed previously that instead of having 2 commands for refreshing > subscriptions we should have a single refresh command: > > ALTER SUBSCRIPTION name REFRESH PUBLICATION [TABLES|SEQUENCES] [ WITH > ( copy_data [= true|false] ) ] > > Why? > > - IMO it is less confusing than having 2 commands that both refresh > sequences in slightly different ways > > - It is more flexible because apart from refreshing everything, a user > can choose to refresh only tables or only sequences if desired; IMO > more flexibility is always good. > > - There is no loss of functionality from the current implementation > AFAICT. You can still say "ALTER SUBSCRIPTION sub REFRESH PUBLICATION > SEQUENCES" exactly the same as the patchset allows. > > ~~~ > > So, to continue this proposal, let the meaning of 'copy_data' for > SEQUENCES be as follows: > > - when copy_data == false: it means don't copy data (i.e. don't > synchronize anything). Add/remove sequences from pg_subscriber_rel as > needed. > > - when copy_data == true: it means to copy data (i.e. synchronize) for > all sequences. Add/remove sequences from pg_subscriber_rel as needed) >
I find overloading the copy_data option more confusing than adding a new variant for REFRESH. To make it clear, we can even think of extending the command as ALTER SUBSCRIPTION name REFRESH PUBLICATION ALL SEQUENCES or something like that. I don't know where there is a need or not but one can imagine extending it as ALTER SUBSCRIPTION name REFRESH PUBLICATION SEQUENCES [<seq_name_1>, <seq_name_2>, ..]. This will allow to selectively refresh the sequences. -- With Regards, Amit Kapila.
