Would TimeUnit.MILLISECONDS.toMicros( myDate.getTime() ) work for producing the microsecond timestamp ?
On Wed, May 13, 2015 at 4:09 PM, Ali Akhtar <ali.rac...@gmail.com> wrote: > If specifying 'using' timestamp, the docs say to provide microseconds, but > where are these microseconds obtained from? I have regular java.util.Date > objects, I can get the time in milliseconds (i.e the unix timestamp), how > would I convert that to microseconds? > > On Wed, May 13, 2015 at 3:56 PM, Ali Akhtar <ali.rac...@gmail.com> wrote: > >> Thanks Peter, that's interesting. I didn't know of that option. >> >> If updates don't create tombstones (and i'm already taking pains to >> ensure no nulls are present in queries), then is there no cost to just >> submitting an update for everything regardless of whether lastModified has >> changed? >> >> Thanks. >> >> On Wed, May 13, 2015 at 3:38 PM, 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. >>> >> >> >
