Re: Read during digest mismatch
If consistency is two, don't we just send data request to one and digest request to another? On Mon, Nov 12, 2012 at 2:49 AM, Jonathan Ellis jbel...@gmail.com wrote: Correct. Which is one reason there is a separate setting for cross-datacenter read repair, by the way. On Thu, Nov 8, 2012 at 4:43 PM, sankalp kohli kohlisank...@gmail.com wrote: Hi, Lets say I am reading with consistency TWO and my replication is 3. The read is eligible for global read repair. It will send a request to get data from one node and a digest request to two. If there is a digest mismatch, what I am reading from the code looks like it will get the data from all three nodes and do a resolve of the data before returning to the client. Is it correct or I am readind the code wrong? Also if this is correct, look like if the third node is in other DC, the read will slow down even when the consistency was TWO? Thanks, Sankalp -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Read during digest mismatch
I think the code base does not benefit from having too many different read code paths. Logically what your suggesting is reasonable, but you have to consider the case of one being slow to respond. Then what? On Tuesday, November 13, 2012, Manu Zhang owenzhang1...@gmail.com wrote: If consistency is two, don't we just send data request to one and digest request to another? On Mon, Nov 12, 2012 at 2:49 AM, Jonathan Ellis jbel...@gmail.com wrote: Correct. Which is one reason there is a separate setting for cross-datacenter read repair, by the way. On Thu, Nov 8, 2012 at 4:43 PM, sankalp kohli kohlisank...@gmail.com wrote: Hi, Lets say I am reading with consistency TWO and my replication is 3. The read is eligible for global read repair. It will send a request to get data from one node and a digest request to two. If there is a digest mismatch, what I am reading from the code looks like it will get the data from all three nodes and do a resolve of the data before returning to the client. Is it correct or I am readind the code wrong? Also if this is correct, look like if the third node is in other DC, the read will slow down even when the consistency was TWO? Thanks, Sankalp -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Read during digest mismatch
From my understanding, if CL = 2, one read, one digest are sent. Only if it is read repair, digest is sent to all replicates. Thanks. -Wei Sent from my Samsung smartphone on ATT Original message Subject: Re: Read during digest mismatch From: Edward Capriolo edlinuxg...@gmail.com To: user@cassandra.apache.org user@cassandra.apache.org CC: I think the code base does not benefit from having too many different read code paths. Logically what your suggesting is reasonable, but you have to consider the case of one being slow to respond. Then what? On Tuesday, November 13, 2012, Manu Zhang owenzhang1...@gmail.com wrote: If consistency is two, don't we just send data request to one and digest request to another? On Mon, Nov 12, 2012 at 2:49 AM, Jonathan Ellis jbel...@gmail.com wrote: Correct. Which is one reason there is a separate setting for cross-datacenter read repair, by the way. On Thu, Nov 8, 2012 at 4:43 PM, sankalp kohli kohlisank...@gmail.com wrote: Hi, Lets say I am reading with consistency TWO and my replication is 3. The read is eligible for global read repair. It will send a request to get data from one node and a digest request to two. If there is a digest mismatch, what I am reading from the code looks like it will get the data from all three nodes and do a resolve of the data before returning to the client. Is it correct or I am readind the code wrong? Also if this is correct, look like if the third node is in other DC, the read will slow down even when the consistency was TWO? Thanks, Sankalp -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Read during digest mismatch
Thats correct On Tue, Nov 13, 2012 at 7:06 PM, Wz1975 wz1...@yahoo.com wrote: From my understanding, if CL = 2, one read, one digest are sent. Only if it isread repair, digest is sent to all replicates. Thanks. -Wei Sent from my Samsung smartphone on ATT Original message Subject: Re: Read during digest mismatch From: Edward Capriolo edlinuxg...@gmail.com To: user@cassandra.apache.org user@cassandra.apache.org CC: I think the code base does not benefit from having too many different read code paths. Logically what your suggesting is reasonable, but you have to consider the case of one being slow to respond. Then what? On Tuesday, November 13, 2012, Manu Zhang owenzhang1...@gmail.com wrote: If consistency is two, don't we just send data request to one and digest request to another? On Mon, Nov 12, 2012 at 2:49 AM, Jonathan Ellis jbel...@gmail.com wrote: Correct. Which is one reason there is a separate setting for cross-datacenter read repair, by the way. On Thu, Nov 8, 2012 at 4:43 PM, sankalp kohli kohlisank...@gmail.com wrote: Hi, Lets say I am reading with consistency TWO and my replication is 3. The read is eligible for global read repair. It will send a request to get data from one node and a digest request to two. If there is a digest mismatch, what I am reading from the code looks like it will get the data from all three nodes and do a resolve of the data before returning to the client. Is it correct or I am readind the code wrong? Also if this is correct, look like if the third node is in other DC, the read will slow down even when the consistency was TWO? Thanks, Sankalp -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Read during digest mismatch
Correct. Which is one reason there is a separate setting for cross-datacenter read repair, by the way. On Thu, Nov 8, 2012 at 4:43 PM, sankalp kohli kohlisank...@gmail.com wrote: Hi, Lets say I am reading with consistency TWO and my replication is 3. The read is eligible for global read repair. It will send a request to get data from one node and a digest request to two. If there is a digest mismatch, what I am reading from the code looks like it will get the data from all three nodes and do a resolve of the data before returning to the client. Is it correct or I am readind the code wrong? Also if this is correct, look like if the third node is in other DC, the read will slow down even when the consistency was TWO? Thanks, Sankalp -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Read during digest mismatch
Hi, Lets say I am reading with consistency TWO and my replication is 3. The read is eligible for global read repair. It will send a request to get data from one node and a digest request to two. If there is a digest mismatch, what I am reading from the code looks like it will get the data from all three nodes and do a resolve of the data before returning to the client. Is it correct or I am readind the code wrong? Also if this is correct, look like if the third node is in other DC, the read will slow down even when the consistency was TWO? Thanks, Sankalp
