Thanks Alex for confirming Le 30 sept. 2019 09:17, "Oleksandr Shulgin" <oleksandr.shul...@zalando.de> a écrit :
> On Sun, Sep 29, 2019 at 9:42 AM DuyHai Doan <doanduy...@gmail.com> wrote: > >> Thanks Jeff for sharing the ideas. I have some question though: >> >> - CQLSSTableWriter and explicitly break between windows --> Even if >> you break between windows, If we have data worth of 1 years it would >> requires us to use CQLSSTableWriter during 1 year (365 days) because >> the write time taken into account when flushing to SSTable is the >> current clock timestamp : >> >> https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/io/sstable/CQLSSTableWriter.java#L252-L259 >> > > Well, it's not obvious from that block of code alone if one cannot > override the write time. But if that's the case, maybe you want to > subclass it and extend for that possibility. > > What we're looking for is a way to load 1 year of data and forcing >> write timestamp to the past so that the initial loading operation is >> seen by TWCS as if we have loaded the data normally day by day during >> 1 year >> >> - Use the normal write path for a single window at a time, explicitly >> calling flush between windows. --> I don't understand how calling >> flush will trigger windowing in TWCS, as far as I know, it is based on >> write time. And by the way, can we load data using normal CQL and just >> forcing the write time to be in the past so that TWCS will trigger >> compaction properly ? >> > > Exactly. If you go for this option, you should specify the write time > explicitly by adding `USING TIMESTAMP :xxx` to your CQL statement. > > -- > Alex > >
