They exist because when using OPP they are useful and make sense.
On Wed, Jun 2, 2010 at 8:59 AM, David Boxenhorn <da...@lookin2.com> wrote: > So why do the "start" and "finish" range parameters exist? > > On Wed, Jun 2, 2010 at 3:53 PM, Ben Browning <ben...@gmail.com> wrote: >> >> Martin, >> >> On Wed, Jun 2, 2010 at 8:34 AM, Dr. Martin Grabmüller >> <martin.grabmuel...@eleven.de> wrote: >> > I think you can specify an end key, but it should be a key which does >> > exist >> > in your column family. >> >> >> Logically, it doesn't make sense to ever specify an end key with >> random partitioner. If you specified a start key of "aaa" and and end >> key of "aac" you might get back as results "aaa", "zfc", "hik", etc. >> And, even if you have a key of "aab" it might not show up. Key ranges >> only make sense with order-preserving partitioner. The only time to >> ever use a key range with random partitioner is when you want to >> iterate over all keys in the CF. >> >> Ben >> >> >> > But maybe I'm off the track here and someone else here knows more about >> > this >> > key range stuff. >> > >> > Martin >> > >> > ________________________________ >> > From: David Boxenhorn [mailto:da...@lookin2.com] >> > Sent: Wednesday, June 02, 2010 2:30 PM >> > To: user@cassandra.apache.org >> > Subject: Re: Range search on keys not working? >> > >> > In other words, I should check the values as I iterate, and stop >> > iterating >> > when I get out of range? >> > >> > I'll try that! >> > >> > On Wed, Jun 2, 2010 at 3:15 PM, Dr. Martin Grabmüller >> > <martin.grabmuel...@eleven.de> wrote: >> >> >> >> When not using OOP, you should not use something like 'CATEGORY/' as >> >> the >> >> end key. >> >> Use the empty string as the end key and limit the number of returned >> >> keys, >> >> as you did with >> >> the 'max' value. >> >> >> >> If I understand correctly, the end key is used to generate an end token >> >> by >> >> hashing it, and >> >> there is not the same correspondence between 'CATEGORY' and 'CATEGORY/' >> >> as >> >> for >> >> hash('CATEGORY') and hash('CATEGORY/'). >> >> >> >> At least, this was the explanation I gave myself when I had the same >> >> problem. >> >> >> >> The solution is to iterate through the keys by always using the last >> >> key >> >> returned as the >> >> start key for the next call to get_range_slices, and the to drop the >> >> first >> >> element from >> >> the result. >> >> >> >> HTH, >> >> Martin >> >> >> >> ________________________________ >> >> From: David Boxenhorn [mailto:da...@lookin2.com] >> >> Sent: Wednesday, June 02, 2010 2:01 PM >> >> To: user@cassandra.apache.org >> >> Subject: Re: Range search on keys not working? >> >> >> >> The previous thread where we discussed this is called, "key is sorted?" >> >> >> >> >> >> On Wed, Jun 2, 2010 at 2:56 PM, David Boxenhorn <da...@lookin2.com> >> >> wrote: >> >>> >> >>> I'm not using OPP. But I was assured on earlier threads (I asked >> >>> several >> >>> times to be sure) that it would work as stated below: the results >> >>> would not >> >>> be ordered, but they would be correct. >> >>> >> >>> On Wed, Jun 2, 2010 at 2:51 PM, Torsten Curdt <tcu...@vafer.org> >> >>> wrote: >> >>>> >> >>>> Sounds like you are not using an order preserving partitioner? >> >>>> >> >>>> On Wed, Jun 2, 2010 at 13:48, David Boxenhorn <da...@lookin2.com> >> >>>> wrote: >> >>>> > Range search on keys is not working for me. I was assured in >> >>>> > earlier >> >>>> > threads >> >>>> > that range search would work, but the results would not be ordered. >> >>>> > >> >>>> > I'm trying to get all the rows that start with "CATEGORY." >> >>>> > >> >>>> > I'm doing: >> >>>> > >> >>>> > String start = "CATEGORY."; >> >>>> > . >> >>>> > . >> >>>> > . >> >>>> > keyspace.getSuperRangeSlice(columnParent, slicePredicate, start, >> >>>> > "CATEGORY/", max) >> >>>> > . >> >>>> > . >> >>>> > . >> >>>> > >> >>>> > in a loop, setting start to the last key each time - but I'm >> >>>> > getting >> >>>> > rows >> >>>> > that don't start with "CATEGORY."!! >> >>>> > >> >>>> > How do I get all rows that start with "CATEGORY."? >> >>> >> >> >> > >> > > >
