On Wed, Mar 20, 2024 at 1:51 PM Bertrand Drouvot <bertranddrouvot...@gmail.com> wrote: > > On Wed, Mar 20, 2024 at 12:48:55AM +0530, Bharath Rupireddy wrote: > > > > 2. last_inactive_at and inactive_timeout are now tracked in on-disk > > replication slot data structure. > > Should last_inactive_at be tracked on disk? Say the engine is down for a > period > of time > inactive_timeout then the slot will be invalidated after the engine > re-start (if no activity before we invalidate the slot). Should the time the > engine is down be counted as "inactive" time? I've the feeling it should not, > and > that we should only take into account inactive time while the engine is up. >
Good point. The question is how do we achieve this without persisting the 'last_inactive_at'? Say, 'last_inactive_at' for a particular slot had some valid value before we shut down but it still didn't cross the configured 'inactive_timeout' value, so, we won't be able to invalidate it. Now, after the restart, as we don't know the last_inactive_at's value before the shutdown, we will initialize it with 0 (this is what Bharath seems to have done in the latest v13-0002* patch). After this, even if walsender or backend never acquires the slot, we won't invalidate it. OTOH, if we track 'last_inactive_at' on the disk, after, restart, we could initialize it to the current time if the value is non-zero. Do you have any better ideas? -- With Regards, Amit Kapila.
