intervals on dedupe and set blocks

[jacqui]

A couple people at the BBC asked why the dedupe block doesn't have an interval/ttl on it, which made me wonder too (ditto the set block). As shown in this screenshot, the cache has a ttl rule:

[mikedewar]

I think this is super important. They could all do with a "clear", too.

[jacqui]

Assigning to me.

[jacqui]

Question: can we standardize how we refer to time windows? Like, could these all use the same term?

• Interval: PackByInterval, Ticker, ToNSQMulti
• TimeToLive: Cache
• Window: Count, Histogram, MovingAverage

I'm a bit divided as they're slightly different. The "TimeToLive" one bugs me the most I guess. What do you think?

[mikedewar]

ooh I like this question.

So there are three concepts here that might be one? If we can figure out the one unifying thing then the name should resolve itself. So:

1. Interval is the time between events. Between the events there is nothing.
2. Window is a period of time over which to aggregate.
3. TTL is the interval between deletion events.

So TTL is a type of Interval - the Interval is the time between insertion and deletion, which are both events. A window doesn't have associated events - it's always the time from some point in time, like "now" to some other point in time.

So maybe we could figure out how to ditch TTL and keep the other two? The only downside is that TTL is quite a broadly understood concept specific to stores.