Hi,
apologies for the late reply as I have been OOO. I have done some
profiling and results look virtually identical on trunk and 14227. I
have attached some screenshots to the ticket
https://issues.apache.org/jira/browse/CASSANDRA-14227. Unless my eyes
are fooling me everything in the jfrs look the same.
Regards
On 30/9/22 9:44, Berenguer Blasi wrote:
Hi Benedict,
thanks for the reply! Yes some profiling is probably needed, then we
can see if going down the delta encoding big refactor rabbit hole is
worth it?
Let's see what other concerns people bring up.
Thx.
On 29/9/22 11:12, Benedict Elliott Smith wrote:
My only slight concern with this approach is the additional memory
pressure. Since 64yrs should be plenty at any moment in time, I
wonder if it wouldn’t be better to represent these times as deltas
from the nowInSec being used to process the query. So, long math
would only be used to normalise the times to this nowInSec (from
whatever is stored in the sstable) within a method, and ints would be
stored in memtables and any objects used for processing.
This might admittedly be more work, but I don’t believe it should be
too challenging - we can introduce a method deletionTime(int
nowInSec) that returns a long value by adding nowInSec to the
deletionTime, and make the underlying value private, refactoring call
sites?
On 29 Sep 2022, at 09:37, Berenguer Blasi <berenguerbl...@gmail.com>
wrote:
Hi all,
I have taken a stab in a PR you can find attached in the ticket. Mainly:
- I have moved deletion times, gc and nowInSec timestamps to long.
That should get us past the 2038 limit.
- TTL is maxed now to 68y. Think CQL API compatibility and a sort of
a 'free' guardrail.
- A new NONE overflow policy is the default but everything is
backwards compatible by keeping the previous ones in place. Think
upgrade scenarios or apps relying on the previous behavior.
- The new limit is around year 292,471,208,677 which sounds ok given
the Sun will start collapsing in 3 to 5 billion years :-)
- Please feel free to drop by the ticket and take a look at the PR
even if it's cursory
Thx in advance.
