> Is that a feature that could possibly be developed one day ? No. Timestamps are essentially internal implementation used to resolve different values for the same column.
> With "min_compaction_level_threshold" did you mean "min_compaction_threshold" > ? If so, why should I do that, what are the advantage/inconvenient of > reducing this value ? Yes, min_compaction_threshold, my bad. If you have a wide row and delete a lot of values you will end up with a lot of tombstones. These may dramatically reduce the read performance until they are purged. Reducing the compaction threshold makes compaction happen more frequently. > Looking at the doc I saw that: "max_compaction_threshold: Ignored in > Cassandra 1.1 and later.". How to ensure that I'll always keep a small amount > of SSTables then ? AFAIK it's not. There may be some confusion about the location of the settings in CLI vs CQL. Can you point to the docs. Cheers ----------------- Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton http://www.thelastpickle.com On 13/02/2013, at 10:14 PM, Alain RODRIGUEZ <arodr...@gmail.com> wrote: > Hi Aaron, once again thanks for this answer. >> "So is it possible to delete all the data inserted in some CF between 2 >> dates or data older than 1 month ?" > "No. " > > Why is there no way of deleting or getting data using the internal timestamp > stored alongside of any inserted column (as described here: > http://www.datastax.com/docs/1.1/ddl/column_family#standard-columns) ? Is > that a feature that could possibly be developed one day ? It could be useful > to perform delete of old data or to bring to a dev cluster just the last week > of data for example. > > With "min_compaction_level_threshold" did you mean "min_compaction_threshold" > ? If so, why should I do that, what are the advantage/inconvenient of > reducing this value ? > > Looking at the doc I saw that: "max_compaction_threshold: Ignored in > Cassandra 1.1 and later.". How to ensure that I'll always keep a small amount > of SSTables then ? Why is this deprecated ? > > Alain > > > 2013/2/12 aaron morton <aa...@thelastpickle.com> >> So is it possible to delete all the data inserted in some CF between 2 dates >> or data older than 1 month ? > No. > > You need to issue row level deletes. If you don't know the row key you'll > need to do range scans to locate them. > > If you are deleting parts of wide rows consider reducing the > min_compaction_level_threshold on the CF to 2 > > Cheers > > > ----------------- > Aaron Morton > Freelance Cassandra Developer > New Zealand > > @aaronmorton > http://www.thelastpickle.com > > On 12/02/2013, at 4:21 AM, Alain RODRIGUEZ <arodr...@gmail.com> wrote: > >> Hi, >> >> I would like to know if there is a way to delete old/unused data easily ? >> >> I know about TTL but there are 2 limitations of TTL: >> >> - AFAIK, there is no TTL on counter columns >> - TTL need to be defined at write time, so it's too late for data already >> inserted. >> >> I also could use a standard "delete" but it seems inappropriate for such a >> massive. >> >> In some cases, I don't know the row key and would like to delete all the >> rows starting by, let's say, "1050#..." >> >> Even better, I understood that columns are always inserted in C* with (name, >> value, timestamp). So is it possible to delete all the data inserted in some >> CF between 2 dates or data older than 1 month ? >> >> Alain > >
