On Wed, Apr 28, 2021 at 3:25 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Wed, Apr 28, 2021 at 9:37 AM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > > > On Wed, Apr 28, 2021 at 12:29 PM Amit Kapila <amit.kapil...@gmail.com> > > wrote: > > > > > > On Tue, Apr 27, 2021 at 11:02 AM vignesh C <vignes...@gmail.com> wrote: > > > > > > > > On Tue, Apr 27, 2021 at 9:48 AM vignesh C <vignes...@gmail.com> wrote: > > > > > > > > > > > > > Attached patch has the changes to update statistics during > > > > spill/stream which prevents the statistics from being lost during > > > > interrupt. > > > > > > > > > > void > > > -UpdateDecodingStats(LogicalDecodingContext *ctx) > > > +UpdateDecodingStats(ReorderBuffer *rb) > > > > > > I don't think you need to change this interface because > > > reorderbuffer->private_data points to LogicalDecodingContext. See > > > StartupDecodingContext. > > > > +1 > > > > With this approach, we could still miss the totalTxns and totalBytes > > updates if the decoding a large but less than > > logical_decoding_work_mem is interrupted, right? > > > > Right, but is there some simple way to avoid that? I see two > possibilities (a) store stats in ReplicationSlot and then send them at > ReplicationSlotRelease but that will lead to an increase in shared > memory usage and as per the discussion above, we don't want that, (b) > send intermediate stats after decoding say N changes but for that, we > need to additionally compute the size of each change which might add > some overhead.
Right. > I am not sure if any of these alternatives are a good idea. What do > you think? Do you have any other ideas for this? I've been considering some ideas but don't come up with a good one yet. It’s just an idea and not tested but how about having CreateDecodingContext() register before_shmem_exit() callback with the decoding context to ensure that we send slot stats even on interruption. And FreeDecodingContext() cancels the callback. Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
