Doubt in Row key range scan
Dear all I have stored my data into Cassandra database in the format tickerID_date. Now when I specify the row key range like 1_2012/05/24(start) to 1_2012/05/27(end) it says that the end key md5 value is lesser than start key md5 value. So I changed my start key to 1_2012/05/27 and end key to 1_2012/05/24, then I got all the keys even which are not in my range like 67_2012/05/23 and 54_2012/05/28. I am using Thrift API. Please help me as I want only the columns of 1_2012/05/24, 1_2012/05/25 , 1_2012/05/26 and 1_2012/05/27. Prakrati Agrawal | Developer - Big Data(ID)| 9731648376 | www.mu-sigma.com This email message may contain proprietary, private and confidential information. The information transmitted is intended only for the person(s) or entities to which it is addressed. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited and may be illegal. If you received this in error, please contact the sender and delete the message from your system. Mu Sigma takes all reasonable steps to ensure that its electronic communications are free from viruses. However, given Internet accessibility, the Company cannot accept liability for any virus introduced by this e-mail or any attachment and you are advised to use up-to-date virus checking software.
Re: Doubt in Row key range scan
Hi, It's normal. Keys to replicas are determined with a hash (md5) when using the random partitionner (which you are using I guess). You probably want to switch to the order preserving partionner or tweak your data model in order to rely on 2nd index for such filtering. - Pierre -Original Message- From: Prakrati Agrawal prakrati.agra...@mu-sigma.com Date: Mon, 28 May 2012 04:39:46 To: user@cassandra.apache.orguser@cassandra.apache.org Reply-To: user@cassandra.apache.org Subject: Doubt in Row key range scan Dear all I have stored my data into Cassandra database in the format tickerID_date. Now when I specify the row key range like 1_2012/05/24(start) to 1_2012/05/27(end) it says that the end key md5 value is lesser than start key md5 value. So I changed my start key to 1_2012/05/27 and end key to 1_2012/05/24, then I got all the keys even which are not in my range like 67_2012/05/23 and 54_2012/05/28. I am using Thrift API. Please help me as I want only the columns of 1_2012/05/24, 1_2012/05/25 , 1_2012/05/26 and 1_2012/05/27. Prakrati Agrawal | Developer - Big Data(ID)| 9731648376 | www.mu-sigma.com This email message may contain proprietary, private and confidential information. The information transmitted is intended only for the person(s) or entities to which it is addressed. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited and may be illegal. If you received this in error, please contact the sender and delete the message from your system. Mu Sigma takes all reasonable steps to ensure that its electronic communications are free from viruses. However, given Internet accessibility, the Company cannot accept liability for any virus introduced by this e-mail or any attachment and you are advised to use up-to-date virus checking software.
Re: Doubt in Row key range scan
You are using the Random Partitioner. Using the RP is a good thing because you avoid hot spots, but it has its defaults too. You can't scan a slice of row, they won't be ordered because all your keys are stored using their md5 values. You should review your data model to use columns to order your data. Alain 2012/5/28 Prakrati Agrawal prakrati.agra...@mu-sigma.com: Dear all I have stored my data into Cassandra database in the format “tickerID_date”. Now when I specify the row key range like 1_2012/05/24(start) to 1_2012/05/27(end) it says that the end key md5 value is lesser than start key md5 value. So I changed my start key to 1_2012/05/27 and end key to 1_2012/05/24, then I got all the keys even which are not in my range like 67_2012/05/23 and 54_2012/05/28. I am using Thrift API. Please help me as I want only the columns of 1_2012/05/24, 1_2012/05/25 , 1_2012/05/26 and 1_2012/05/27. Prakrati Agrawal | Developer - Big Data(ID)| 9731648376 | www.mu-sigma.com This email message may contain proprietary, private and confidential information. The information transmitted is intended only for the person(s) or entities to which it is addressed. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited and may be illegal. If you received this in error, please contact the sender and delete the message from your system. Mu Sigma takes all reasonable steps to ensure that its electronic communications are free from viruses. However, given Internet accessibility, the Company cannot accept liability for any virus introduced by this e-mail or any attachment and you are advised to use up-to-date virus checking software.
RE: Doubt in Row key range scan
Please could you tell me how to tweak my data model to rely on 2nd index ? Thank you Prakrati Agrawal | Developer - Big Data(ID)| 9731648376 | www.mu-sigma.com From: Pierre Chalamet [mailto:pie...@chalamet.net] Sent: Monday, May 28, 2012 3:31 PM To: user@cassandra.apache.org Subject: Re: Doubt in Row key range scan Hi, It's normal. Keys to replicas are determined with a hash (md5) when using the random partitionner (which you are using I guess). You probably want to switch to the order preserving partionner or tweak your data model in order to rely on 2nd index for such filtering. - Pierre From: Prakrati Agrawal prakrati.agra...@mu-sigma.com Date: Mon, 28 May 2012 04:39:46 -0500 To: user@cassandra.apache.orguser@cassandra.apache.org ReplyTo: user@cassandra.apache.org Subject: Doubt in Row key range scan Dear all I have stored my data into Cassandra database in the format tickerID_date. Now when I specify the row key range like 1_2012/05/24(start) to 1_2012/05/27(end) it says that the end key md5 value is lesser than start key md5 value. So I changed my start key to 1_2012/05/27 and end key to 1_2012/05/24, then I got all the keys even which are not in my range like 67_2012/05/23 and 54_2012/05/28. I am using Thrift API. Please help me as I want only the columns of 1_2012/05/24, 1_2012/05/25 , 1_2012/05/26 and 1_2012/05/27. Prakrati Agrawal | Developer - Big Data(ID)| 9731648376 | www.mu-sigma.com This email message may contain proprietary, private and confidential information. The information transmitted is intended only for the person(s) or entities to which it is addressed. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited and may be illegal. If you received this in error, please contact the sender and delete the message from your system. Mu Sigma takes all reasonable steps to ensure that its electronic communications are free from viruses. However, given Internet accessibility, the Company cannot accept liability for any virus introduced by this e-mail or any attachment and you are advised to use up-to-date virus checking software. This email message may contain proprietary, private and confidential information. The information transmitted is intended only for the person(s) or entities to which it is addressed. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited and may be illegal. If you received this in error, please contact the sender and delete the message from your system. Mu Sigma takes all reasonable steps to ensure that its electronic communications are free from viruses. However, given Internet accessibility, the Company cannot accept liability for any virus introduced by this e-mail or any attachment and you are advised to use up-to-date virus checking software.
Re: Doubt in Row key range scan
Check this out: http://www.anuff.com/2011/02/indexing-in-cassandra.html#more Or just google for wide row indexes. On May 28, 2012, at 11:22 AM, Prakrati Agrawal wrote: Please could you tell me how to tweak my data model to rely on 2nd index ? Thank you Prakrati Agrawal | Developer - Big Data(ID)| 9731648376 | www.mu-sigma.com From: Pierre Chalamet [mailto:pie...@chalamet.net] Sent: Monday, May 28, 2012 3:31 PM To: user@cassandra.apache.org Subject: Re: Doubt in Row key range scan Hi, It's normal. Keys to replicas are determined with a hash (md5) when using the random partitionner (which you are using I guess). You probably want to switch to the order preserving partionner or tweak your data model in order to rely on 2nd index for such filtering. - Pierre From: Prakrati Agrawal prakrati.agra...@mu-sigma.com Date: Mon, 28 May 2012 04:39:46 -0500 To: user@cassandra.apache.orguser@cassandra.apache.org ReplyTo: user@cassandra.apache.org Subject: Doubt in Row key range scan Dear all I have stored my data into Cassandra database in the format “tickerID_date”. Now when I specify the row key range like 1_2012/05/24(start) to 1_2012/05/27(end) it says that the end key md5 value is lesser than start key md5 value. So I changed my start key to 1_2012/05/27 and end key to 1_2012/05/24, then I got all the keys even which are not in my range like 67_2012/05/23 and 54_2012/05/28. I am using Thrift API. Please help me as I want only the columns of 1_2012/05/24, 1_2012/05/25 , 1_2012/05/26 and 1_2012/05/27. Prakrati Agrawal | Developer - Big Data(ID)| 9731648376 | www.mu-sigma.com This email message may contain proprietary, private and confidential information. The information transmitted is intended only for the person(s) or entities to which it is addressed. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited and may be illegal. If you received this in error, please contact the sender and delete the message from your system. Mu Sigma takes all reasonable steps to ensure that its electronic communications are free from viruses. However, given Internet accessibility, the Company cannot accept liability for any virus introduced by this e-mail or any attachment and you are advised to use up-to-date virus checking software. This email message may contain proprietary, private and confidential information. The information transmitted is intended only for the person(s) or entities to which it is addressed. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited and may be illegal. If you received this in error, please contact the sender and delete the message from your system. Mu Sigma takes all reasonable steps to ensure that its electronic communications are free from viruses. However, given Internet accessibility, the Company cannot accept liability for any virus introduced by this e-mail or any attachment and you are advised to use up-to-date virus checking software. Cumprimentos, Luís Ferreira
