Thanks. So supplying the timestamp with the update (via using) should fix that, right? (By skipping updates where lastModified < dbLastModified).
I'm currently doing TimeUnit.MILLISECONDS.toMicros( myDate.getTime() ) and that has worked for inserts, however how do I verify that future updates are ignored and aren't run again? On Wed, May 13, 2015 at 4:29 PM, Ken Hancock <ken.hanc...@schange.com> wrote: > While updates don't create tombstones, overwrites create a similar > performance penalty at the read phase. That key will need to be fetched > from every SSTable where it resides so the "most recent" column can be > returned. > > > > > On Wed, May 13, 2015 at 6:38 AM, Peer, Oded <oded.p...@rsa.com> wrote: > >> You can use the “last modified” value as the TIMESTAMP for your UPDATE >> operation. >> >> This way the values will only be updated if lastModified date > the >> lastModified you have in the DB. >> >> >> >> Updates to values don’t create tombstones. Only deletes (either by >> executing delete, inserting a null value or by setting a TTL) create >> tombstones. >> >> >> >> >> >> *From:* Ali Akhtar [mailto:ali.rac...@gmail.com] >> *Sent:* Wednesday, May 13, 2015 1:27 PM >> *To:* user@cassandra.apache.org >> *Subject:* Updating only modified records (where lastModified < current >> date) >> >> >> >> I'm running some ETL jobs, where the pattern is the following: >> >> >> >> 1- Get some records from an external API, >> >> >> >> 2- For each record, see if its lastModified date > the lastModified i >> have in db (or if I don't have that record in db) >> >> >> >> 3- If lastModified < dbLastModified, the item wasn't changed, ignore it. >> Otherwise, run an update query and update that record. >> >> >> >> (It is rare for existing records to get updated, so I'm not that >> concerned about tombstones). >> >> >> >> The problem however is, since I have to query each record's lastModified, >> one at a time, that's adding a major bottleneck to my job. >> >> >> >> E.g if I have 6k records, I have to run a total of 6k 'select >> lastModified from myTable where id = ?' queries. >> >> >> >> Is there a better way, am I doing anything wrong, etc? Any suggestions >> would be appreciated. >> >> >> >> Thanks. >> > > > > > >
