Re: what consistency level should I set when using IF NOT EXIST or UPDATE IF statements ?

he python driver docs explain this pretty well, I think: > http://datastax.github.io/python-driver/api/cassandra/query.html#cassandra.query.Statement.serial_consistency_level > > On Thu, Jan 7, 2016 at 3:44 AM, Hiroyuki Yamada <mogwa...@gmail.com> > wrote: > >> Hi,

Re: what consistency level should I set when using IF NOT EXIST or UPDATE IF statements ?

Can anyone answer my questions ? I think the current datastax documents including python's one don't describe how we should set consistency with lightweight transactions precisely. Regards, Hiro On Fri, Jan 8, 2016 at 11:48 AM, Hiroyuki Yamada <mogwa...@gmail.com> wrote: > Tha

Re: what consistency level should I set when using IF NOT EXIST or UPDATE IF statements ?

se you can use > any CL except SERIAL/LOCAL_SERIAL > > Setting the consistency level for Paxos is useful in the context of multi > data centers only. SERIAL => require a majority wrt RF in all DCs. > LOCAL_SERIAL => majority wrt RF in local DC only > > Hope that helps

Re: How can I make Cassandra stable in a 2GB RAM node environment ?

Thank you all to respond and discuss my question. I agree with you all basically, but, I think, in Cassandra case, it seems a matter of how much data we use with how much memory we have. As Jack's (and datastax's) suggestion, I also used 4GM RAM machine (t2.medium) with 1 billion records (about

How can I make Cassandra stable in a 2GB RAM node environment ?

Hi, I'm working on some POCs for Cassandra with single 2GB RAM node environment and some issues came up with me, so let me ask here. I have tried to insert about 200 million records (about 11GB in size) to the node, and the insertion from an application program seems completed, but something

About the data structure of partition index

Hi, I am wondering how many primary keys are stored in one partition index. As the following documents say, I understand that each

Re: Read operation can read uncommitted data?

Hi, I'm also wondering if failed read/results phase (phase 2 in C* paxos) is recovered by some other reads or not. It seems easier to just return "failed" to clients if the phase 2 failed, because none of proposals are actually initiated. Does anyone know about it ? Thanks, Hiroyuki On Wed,

Re: Authentication with Java driver

Hi, The API seems kind of not correct because credentials should be usually set with a session but actually they are set with a cluster. So, if there are 1000 clients, then with this API it has to create 1000 cluster instances ? 1000 clients seems usual if there are many nodes (say 20) and each

Re: Does recovery continue after truncating a table?

Hi Yuji and Ben, I tried out this revised script and the same issue occurred to me, too. I think it's definitely a bug to be solved asap. >Ben What do you mean "an undocumented limitation" ? Thanks, Hiro On Sat, Nov 26, 2016 at 3:13 PM, Ben Slater wrote: > Nice

Re: How does the "batch" commit log sync works

Hello Satoshi and the community, I am also using commitlog_sync for durability, but I have never modified commitlog_sync_batch_window_in_ms parameter yet, so I wondered if it is working or not. As Satoshi said, I also changed commitlog_sync_batch_window_in_ms (to 1) and restarted C* and

Re: How does the "batch" commit log sync works

ell by tests. It sounds like it is not working. Quick >> suggestion: go back in time maybe to a version like 1.2.X or 0.7 and see if >> it behaves like the yaml suggests it should. >> >> On Thu, Oct 27, 2016 at 11:48 PM, Hiroyuki Yamada <mogwa...@gmail

Re: Benefit of LOCAL_SERIAL consistency

SERT IF >> NOT EXISTS with LOCAL_SERIAL in DC1, then it's possible that a subsequent >> INSERT IF NOT EXISTS on the same record succeeds when using SERIAL because >> SERIAL on 9 replicas = at least 5 replicas. Those 5 replicas which respond >> can come from DC2 and DC3 and thus did

Benefit of LOCAL_SERIAL consistency

Hi, I have been using lightweight transactions for several months now and wondering what is the benefit of having LOCAL_SERIAL serial consistency level. With SERIAL, it achieves global linearlizability, but with LOCAL_SERIAL, it only achieves DC-local linearlizability, which is missing point of

Is it safe to use paxos protocol in LWT from patent perspective ?

Hi all, I'm wondering if it is safe to use paxos protocol in LWT from patent perspective. I found some paxos-related patents here. Does anyone know about this ? Best regards, Hiroyuki

Re: LWT on data mutated by non-LWT operation is valid ?

explanation for my mixed LWT/non-LWT problem. So, it looks like > there can be some edge cases. > > I'd say that if data was inserted a while ago (seconds) there should be no > problems. > > -- > Jacques-Henri Berthemet > > -Original Message- > From: Hiroyuki

Re: LWT on data mutated by non-LWT operation is valid ?

ache.org/jira/browse/CASSANDRA-14304 > > > Regards, > > JH > > > From: Hiroyuki Yamada <mogwa...@gmail.com> > Sent: Saturday, March 24, 2018 4:38:15 AM > To: user@cassandra.apache.org > Subject: LWT on data mutated by non-LWT operatio

LWT on data mutated by non-LWT operation is valid ?

Hi all, I have some question about LWT. I am wondering if LWT works only for data mutated by LWT or not. In other words, doing LWT on some data mutated by non-LWT operations is still valid ? I don't fully understand how system.paxos table works in LWT, but row_key should be empty for a data

Re: Released an ACID-compliant transaction library on top of Cassandra

t; On Tue, Oct 16, 2018, at 12:31 PM, Jeff Jirsa wrote: >>> > This is great! >>> > >>> > -- >>> > Jeff Jirsa >>> > >>> > >>> > > On Oct 16, 2018, at 5:47 PM, Hiroyuki Yamada wrote: >>> > > &

Released an ACID-compliant transaction library on top of Cassandra

intensively and is jepsen-passed. (see jepsen directory for more detail) If you are looking for ACID transaction capability on top of cassandra, Please take a look and give us a feedback or contribution. Best regards, Hiroyuki Yamada

Re: Released an ACID-compliant transaction library on top of Cassandra

, 2018 at 8:52 AM Hiroyuki Yamada wrote: > > Hi all, > > Thank you for the comments and feedbacks. > > As Jonathan pointed out, it relies on LWT and uses the protocol > proposed in the paper. > Please read the design document for more detail. > https://github.com/scalar-lab

Re: Apache Cassandra transactions commit and rollback

Hi Ramya, Scalar DB is one of the options. https://github.com/scalar-labs/scalardb But, first of all, please re-think about your design if you really need it. For example, If eventual consistency between multiple rows are acceptable, and writes are idempotent, then you should go with C* write

Re: A cluster (RF=3) not recovering after two nodes are stopped

Hi, Should I post a bug ? It doesn't seem to be an expected behavior, so I think it should be at least documented somewhere. Thanks, Hiro On Fri, Apr 26, 2019 at 3:17 PM Hiroyuki Yamada wrote: > Hello, > > Thank you for some feedbacks. > > >Ben > Thank you. >

Re: A cluster (RF=3) not recovering after two nodes are stopped

Hi, FYI: I created a bug ticket since I think the behavior is just not right. https://issues.apache.org/jira/browse/CASSANDRA-15138 Thanks, Hiro On Mon, May 13, 2019 at 10:58 AM Hiroyuki Yamada wrote: > Hi, > > Should I post a bug ? > It doesn't seem to be an expected behavior,

Re: Necessary consistency level for LWT writes

Hi Craig, I'm not 100 % sure about some corner cases, but I'm sure that LWT should be used with the following consistency levels usually. LWT write: serial_consistency_level: SERIAL consistency_level: QUORUM LWT read: consistency_level: SERIAL (It's a bit weird and mis-leading as a design that

Re: Necessary consistency level for LWT writes

hat I think is that a read initiated when the Paxos phase is > underway with a consistency level of QUORUM or ALL will not detect that a > Paxos phase is underway and return the old current data. > > Is this correct? > > Thank you for any help! > > Best wishes, > Craig > > &

Re: Cassandra LWT Writes inconsistent

Do you also set SERIAL CONSISTENCY properly ? https://docs.datastax.com/en/archived/cql/3.3/cql/cql_reference/cqlshSerialConsistency.html Hiro On Tue, Jul 9, 2019 at 2:25 PM Jeff Jirsa wrote: > > If applied is false it’s not the first write, the value already exists. > You’ve likely got a

Re: A cluster (RF=3) not recovering after two nodes are stopped

Sorry, I didn't write the version and the configurations. I've tested with C* 3.11.4, and the configurations are mostly set to default except for the replication factor and listen_address for proper networking. Thanks, Hiro On Wed, Apr 24, 2019 at 5:12 PM Hiroyuki Yamada wrote: > Hello

Re: A cluster (RF=3) not recovering after two nodes are stopped

Hello, Sorry again. We found yet another weird thing in this. If we stop nodes with systemctl or just kill (TERM), it causes the problem, but if we kill -9, it doesn't cause the problem. Thanks, Hiro On Wed, Apr 24, 2019 at 11:31 PM Hiroyuki Yamada wrote: > Sorry, I didn't write the vers

A cluster (RF=3) not recovering after two nodes are stopped

Hello, I faced a weird issue when recovering a cluster after two nodes are stopped. It is easily reproduce-able and looks like a bug or an issue to fix, so let me write down the steps to reproduce. === STEPS TO REPRODUCE === * Create a 3-node cluster with RF=3 - node1(seed), node2, node3 *

Re: A cluster (RF=3) not recovering after two nodes are stopped

ents may contain confidential and legally > privileged information. If you are not the intended recipient, do not copy > or disclose its content, but please reply to this email immediately and > highlight the error to the sender and then immediately delete the message. > > > On Wed, 24

Re: A cluster (RF=3) not recovering after two nodes are stopped

legally > privileged information. If you are not the intended recipient, do not copy > or disclose its content, but please reply to this email immediately and > highlight the error to the sender and then immediately delete the message. > > > On Thu, 25 Apr 2019 at 17:26, Hiroyu

Released a simple and integrated backup tool for Apache Cassandra

Hi all, We are pleased to announce the release of a new backup tool for Cassandra called Cassy. https://github.com/scalar-labs/cassy/ It is licensed under Apache 2.0 License so please give it a try. Best regards, Hiroyuki Yamada

Re: [EXTERNAL] Re: loading big amount of data to Cassandra

cassandra-loader is also useful because you don't need to create sstables. https://github.com/brianmhess/cassandra-loader Hiro On Tue, Aug 6, 2019 at 12:15 AM Durity, Sean R wrote: > > DataStax has a very fast bulk load tool - dsebulk. Not sure if it is > available for open source or not. In

Re: Cassandra is not showing a node up hours after restart

Hello Paul, The behavior looks similar to what we experienced and reported. https://issues.apache.org/jira/browse/CASSANDRA-15138 In our testing, "service cassandra stop" makes a cluster sometimes in a wrong state. How about doing kill -9 ? Thanks, Hiro On Sun, Dec 8, 2019 at 7:47 PM Hossein

Re: design principle to manage roll back

As one of the options, you can use (Logged) batch for kind of atomic mutations. I said, "kind of" because it is not really atomic when mutations span multiple partitions. More specifically, the mutations go to all the nodes eventually so intermediate states can be observed and there is no