Re: High disk io read load

> - Node A has 512 tokens and Node B 256. So it has double the load (data). > - Node A also has 2 SSDs, Node B only 1 SSD (according to load) > I very rarely see heterogeneous vnode counts in the same cluster. I would almost guarantee you are the only one doing this with MVs as well. That said,

Re: How does cassandra achieve Linearizability?

Hi, That would work and would help a lot with the dueling proposer issue. A lot of the leader election stuff is designed to reduce the number of roundtrips and not just address the dueling proposer issue. Those will have downtime because it's there for correctness. Just adding an affinity

Re: How does cassandra achieve Linearizability?

On Thu, Feb 16, 2017 at 4:33 PM, Ariel Weisberg wrote: > Hi, > > Classic Paxos doesn't have a leader. There are variants on the original > Lamport approach that will elect a leader (or some other variation like > Mencius) to improve throughput, latency, and performance under

Re: How does cassandra achieve Linearizability?

Hi, Classic Paxos doesn't have a leader. There are variants on the original Lamport approach that will elect a leader (or some other variation like Mencius) to improve throughput, latency, and performance under contention. Cassandra implements the approach from the beginning of "Paxos Made

Re: How does cassandra achieve Linearizability?

@Ariel Weisberg EPaxos looks very interesting as it looks like it doesn't need any designated leader for C* but I am assuming the paxos that is implemented today for LWT's requires Leader election and If so, don't we need to have an odd number of nodes or racks or DC's to satisfy N = 2F + 1

Re: High disk io read load

On Thu, Feb 16, 2017 at 12:38 AM, Benjamin Roth wrote: > It doesn't really look like that: > https://cl.ly/2c3Z1u2k0u2I > > Thats the ReadLatency.count metric aggregated by host which represents the > actual read operations, correct? > > 2017-02-15 23:01 GMT+01:00 Edward

Re: Count(*) is not working

Hi, could you post the output of nodetool cfstats for the table? Cheers, Jan Am 16.02.2017 um 17:00 schrieb Selvam Raman: > I am not getting count as result. Where i keep on getting n number of > results below. > > Read 100 live rows and 1423 tombstone cells for query SELECT * FROM >

Re: sasi index question (read timeout on many selects)

My advice to avoid them is based on the issues that have been filed in Jira. Benjamin Roth is one of the only people talking about his MV usage, and has filed a few JIRAs discussing their problems when bootstrapping new nodes, as well as issues repairing.

Re: Determining if data will be created on Cassandra Write Exceptions

Hi, If my understanding is correct, as long as you know that at least one node acknowledge a write, it will be replicated at some point in the cluster. A retry failure depends on what you consider a failure :) If you absolutely need LOCAL_QUORUM to succeed, and for any reason Cassandra can't at

Re: Count(*) is not working

I am not getting count as result. Where i keep on getting n number of results below. Read 100 live rows and 1423 tombstone cells for query SELECT * FROM keysace.table WHERE token(id) > token(test:ODP0144-0883E-022R-002/047-052) LIMIT 100 (see tombstone_warn_threshold) On Thu, Feb 16, 2017 at

Re: sasi index question (read timeout on many selects)

On 16.02.2017 16:33, Jonathan Haddad wrote: > > Regarding MVs, do not use the ones that shipped with 3.x. They're not > ready for production. Manage it yourself by using a second table and > inserting a second record there. > Out of interest... there is a slight discrepance between the

lots of connection timeouts around same time every day

Hi there - Cluster info: C* 3.9, replicated across 4 EC2 regions (us-east-1, us-west-2, eu-west-1, ap-southeast-1), c4.4xlarge Around the same time every day (~7-8am EST), 2 DC's (eu-west-1 and ap-southeast-1) in our cluster start experiencing a high number of timeouts (Connection.TotalTimeouts

Re: sasi index question (read timeout on many selects)

On 16.02.2017 16:33, Jonathan Haddad wrote: > I agree w/ DuyHai regarding the index. The use case described here is a > terrible one for SASI indexes. > > Regarding MVs, do not use the ones that shipped with 3.x. They're not > ready for production. Manage it yourself by using a second table

Re: Determining if data will be created on Cassandra Write Exceptions

Thanks for the links. I get that all queries need to be idempotent, and we should use retries for data consistency. But, what happens when the retries fail? Then, the data *may* be there. To maintain consistency we need to rollback any created data, correct? tia, rouble On Wed, Feb 15, 2017 at

Re: sasi index question (read timeout on many selects)

I agree w/ DuyHai regarding the index. The use case described here is a terrible one for SASI indexes. Regarding MVs, do not use the ones that shipped with 3.x. They're not ready for production. Manage it yourself by using a second table and inserting a second record there. On Thu, Feb 16,

Re: sasi index question (read timeout on many selects)

Using MV and put id as partition key is your best bet right now. SASI will be too expensive for this simple use case On Thu, Feb 16, 2017 at 3:21 PM, Micha wrote: > > > it's like having a table (sha256 blob primary key, id timeuuid, data1 > text, ., ) > > So both,

Re: sasi index question (read timeout on many selects)

it's like having a table (sha256 blob primary key, id timeuuid, data1 text, ., ) So both, sha256 and id are unique. I would like to query *either* with sha256 *or* with id. I thought this can be done with a sasi index, but it has to be done with a second table (manual way) or with a mv

Re: sasi index question (read timeout on many selects)

[image: Inline image 1] On Thu, Feb 16, 2017 at 3:08 PM, Micha wrote: > > > On 16.02.2017 14:30, DuyHai Doan wrote: > > Why indexing BLOB data ? It does not make any sense > > My partition key is a secure hash sum, I don't index a blob. > > > > >

Re: sasi index question (read timeout on many selects)

No matter what has to be indexed here, the preferrable way is most probably denormalization instead of another index. 2017-02-16 15:09 GMT+01:00 DuyHai Doan : > [image: Inline image 1] > > On Thu, Feb 16, 2017 at 3:08 PM, Micha wrote: > >> >> >> On

Re: sasi index question (read timeout on many selects)

On 16.02.2017 14:30, DuyHai Doan wrote: > Why indexing BLOB data ? It does not make any sense My partition key is a secure hash sum, I don't index a blob.

Re: sasi index question (read timeout on many selects)

Why indexing BLOB data ? It does not make any sense "I thought sasi index is globally held, in contrast to the normal secondary index.." --> Who said that ? It's just wrong On Thu, Feb 16, 2017 at 1:50 PM, Micha wrote: > Hi, > > > my table has (among others) three

Re: Count(*) is not working

With C* 3.10 cqlsh ip --request-timeout=60 Connected to x at 10.10.10.10:9042. [cqlsh 5.0.1 | Cassandra 3.10 | CQL spec 3.4.4 | Native protocol v4] Use HELP for help. cqlsh> USE ; cqlsh:> SELECT count(*) from table; count - 3572579 On 02/16/2017 12:27 PM, Selvam

Re: Count(*) is not working

I am using cassandra 3.9. Primary Key: id text; On Thu, Feb 16, 2017 at 12:25 PM, Cogumelos Maravilha < cogumelosmaravi...@sapo.pt> wrote: > C* version please and partition key. > > On 02/16/2017 12:18 PM, Selvam Raman wrote: > > Hi, > > I want to know the total records count in table. > > I

Count(*) is not working

Hi, I want to know the total records count in table. I fired the below query: select count(*) from tablename; and i have got the below output Read 100 live rows and 1423 tombstone cells for query SELECT * FROM keysace.table WHERE token(id) > token(test:ODP0144-0883E-022R-002/047-052)