1. Make a new table with the same schema. For each node 2. Shutdown node 3. Copy data from Source sstable dir to new sstable dir.
This will do what you want. -- Rahul Singh rahul.si...@anant.us Anant Corporation On Apr 16, 2018, 4:21 PM -0500, Kyrylo Lebediev <kyrylo_lebed...@epam.com>, wrote: > Thanks, Ali. > I just need to copy a large table in production without actual copying by > using hardlinks. After this both tables should be used independently (RW). Is > this a supported way or not? > > Regards, > Kyrill > From: Ali Hubail <ali.hub...@petrolink.com> > Sent: Monday, April 16, 2018 6:51:51 PM > To: user@cassandra.apache.org > Subject: Re: copy from one table to another > > If you want to copy a portion of the data to another table, you can also use > sstable cql writer. It is more of an advanced feature and can be tricky, but > doable. > once you write the new sstables, you can then use the sstableloader to stream > the new data into the new table. > check this out: > https://www.datastax.com/dev/blog/using-the-cassandra-bulk-loader-updated > > I have recently used this to clean up 500 GB worth of sstable data in order > to purge tombstones that were mistakenly generated by the client. > obviously this is not as fast as hardlinks + refresh, but it's much faster > and more efficient than using cql to copy data accross the tables. > take advantage of CQLSSTableWriter.builder.sorted() if you can, and utilize > writetime if you have to. > > Ali Hubail > > Confidentiality warning: This message and any attachments are intended only > for the persons to whom this message is addressed, are confidential, and may > be privileged. If you are not the intended recipient, you are hereby notified > that any review, retransmission, conversion to hard copy, copying, > modification, circulation or other use of this message and any attachments is > strictly prohibited. If you receive this message in error, please notify the > sender immediately by return email, and delete this message and any > attachments from your system. Petrolink International Limited its > subsidiaries, holding companies and affiliates disclaims all responsibility > from and accepts no liability whatsoever for the consequences of any > unauthorized person acting, or refraining from acting, on any information > contained in this message. For security purposes, staff training, to assist > in resolving complaints and to improve our customer service, email > communications may be monitored and telephone calls may be recorded. > > > Kyrylo Lebediev <kyrylo_lebed...@epam.com> > 04/16/2018 10:37 AM > Please respond to > user@cassandra.apache.org > > To > "user@cassandra.apache.org" <user@cassandra.apache.org>, > cc > Subject > Re: copy from one table to another > > > > > > Any issues if we: > > 1) create an new empty table with the same structure as the old one > 2) create hardlinks ("ln without -s"): > .../<newtable>-<newuuid>/<newkeyspacename>-<newtable>-* ---> > .../<oldtable>-<olduuid>/<oldkeyspacename>-<oldtable>-* > 3) run nodetool refresh -- newkeyspacename newtable > > and then query/modify both tables independently/simultaneously? > > In theory, as SSTables are immutable, this should work, but could there be > some hidden issues? > > Regards, > Kyrill > > From: Dmitry Saprykin <saprykin.dmi...@gmail.com> > Sent: Sunday, April 8, 2018 7:33:03 PM > To: user@cassandra.apache.org > Subject: Re: copy from one table to another > > You can copy hardlinks to ALL SSTables from old to new table and then delete > part of data you do not need in a new one. > > On Sun, Apr 8, 2018 at 10:20 AM, Nitan Kainth <nitankai...@gmail.com> wrote: > If it for testing and you don’t need any specific data, just copy a set of > sstables with all files of that sequence and move to target tables directory > and rename it. > > Restart target node or run nodetool refresh > > Sent from my iPhone > > On Apr 8, 2018, at 4:15 AM, onmstester onmstester <onmstes...@zoho.com> wrote: > > Is there any way to copy some part of a table to another table in cassandra? > A large amount of data should be copied so i don't want to fetch data to > client and stream it back to cassandra using cql. > > Sent using Zoho Mail > > >
