Christophe, thanks for your insights,Sorry, I forgot to mention that
currently both tableA and tableB are being updated by application (all newly
inserted/updated records should be identical on A and B), exporting from tableB
and COPY it back later on will result in older data overwrites newly updated
data.
I can only thinking about using COPY tableA to a csv, and then iterate the csv
line by line to insert to tableB using "if not exists" clause to avoid
down-time , but it's error-prone and slow. Not sure whether there is a better
way. Best,Richard
On Monday, October 1, 2018, 4:34:38 PM PDT, Christophe Schmitz
<christo...@instaclustr.com> wrote:
Hi Richard,
You could consider exporting your few thousands record of Table B in a file,
with COPY TO. Then TRUNCATE Table B, copy the SSTable files of TableA to the
data directory of Table A (make sure you flush the memtables first), then run
nodetool refresh. Final step is to load the few thousands record on Table B
with COPY FROM. This will overwrite the data you loaded from the SSTables of
Table A.Overall, there is no downtime on your cluster, there is no downtime on
Table A, yet you need to think about the consequences on Table B if your
application is writing on Table A or Table B during this process.Please test
first :)
Cheers,Christophe
Christophe Schmitz - Instaclustr - Cassandra | Kafka | Spark Consulting
On Tue, 2 Oct 2018 at 09:18 Richard Xin <richardxin...@yahoo.com.invalid> wrote:
I have a tableA with about a few ten millions record, and I have tableB with a
few thousands record,TableA and TableB have exact same schema (except that
tableB doesnt have TTL)
I want to load all data to tableB from tableA EXCEPT for those already on
tableB (we don't want data on tableB to be overwritten)
What's the best to way accomplish this?
Thanks,
