CODEWITHSUNDEEP
user-defined-functionsttlaerospike
Alex Woolford
Alex Woolford

Reputation: 4563

Aerospike: get upsert time without explicitly storing it for records with a TTL

Aerospike is blazingly fast and reliable, but expensive. The cost, for us, is based on the amount of data stored.

We'd like the ability to query records based on their upsert time. Currently, when we add or update a record, we set a bin to the current epoch time and can run scan queries on this bin.

It just occurred to me that Aerospike knows when to expire a record based on when it was upserted, and since we can query the TTL value from the record metadata via a simple UDF, it might be possible to infer the upsert time for records with a TTL. We're effectively using space to store a value that's already known.

Is it possible to access record creation or expiry time, via UDF, without explicitly storing it?

Upvotes: 3

Views: 602

Answers (2)

Amod Pandey
Amod Pandey

Reputation: 1396

void time : This tracks the life of a key in system. This is the time at which key should expire and is used by eviction subsystem.

so ttl is derived from the void time.

As we get ttl from a record, we can only calculate the void time (now + ttl)

Based on what you have, I think you can evaluate the upsert time from ttl only if you add same amount of expiration to all your records, say CONSTANT_EXPIRATION_TIME.

in that case 

upsert_time = now - (CONSTANT_EXPIRATION_TIME - ttl)

HTH

Upvotes: 1

Meher
Meher

Reputation: 2939

At this point, Aerospike only stores the void time along with the record (the time when the record expires). So the upsert time is unfortunately not available. Stay tuned, though, as I heard there were some plans to have some new features that may help you. (I am part of Aerospike's OPS/Support team).

Upvotes: 4

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