Oops, my bad. Not "master node" I meant "system tables". Cassandra has no master nodes, it is entirely peer oriented. I apologize profusely, and hope I have not confused.
*.......* *“Life should not be a journey to the grave with the intention of arriving safely in apretty and well preserved body, but rather to skid in broadside in a cloud of smoke,thoroughly used up, totally worn out, and loudly proclaiming “Wow! What a Ride!” - Hunter ThompsonDaemeon C.M. ReiydelleUSA (+1) 415.501.0198London (+44) (0) 20 8144 9872* On Mon, Mar 16, 2015 at 11:51 PM, 鄢来琼 <laiqiong....@gtafe.com> wrote: > Hi Daemeon, > > Thanks for your response. > > Yes, exactly, your answer clear my doubt. My question is time of table > created on data nodes. > > > > According to your answer, the table’s meta data is recorded on master > node(s), then table will be created on data node(s) when R/W operation is > executed. > > So there are other questions. > > 1, Which node is master node, which algorithm is used by Cassandra to > identify master node; > > 2, Is there a problem if master node is down before actual data written to > data node? Because master node is down, table can not be created on data > nodes. > > > > Regards, > > Peter > > > > > > > > *发件人:* daemeon reiydelle [mailto:daeme...@gmail.com] > *发送时间:* 2015年3月17日 13:38 > *收件人:* user@cassandra.apache.org; Saladi Naidu > *主题:* Re: Is Table created in all the nodes if the default consistency > level used > > > > If I am following your thread correctly, I think you might be confusing > the "creeation" of a table with the "recording of the definition" + > "storage for the table allocated". > > When you define the table, based on your config, the existence of the > table is recorded in the master node(s). But tables are not "created" on > data nodes. Data nodes store the data (or their pieces of it) when actual > data is written to the table ... so creating a table does not cause > memtables (or empty sst's) to be created. When you insert into the table, > and data has to go "someplace", the memtables and sst's start tracking that > data. Does this clarify? > > As an aside, you will only get stale data if the read consistency level > together with the number of nodes that went offline (which hold copies of > the table), allow it: e.g. imagine read consistency 1 and one node with > stale data, etc. > > > > > > > > > > > > * ....... “Life should not be a journey to the grave with the intention of > arriving safely in a pretty and well preserved body, but rather to skid in > broadside in a cloud of smoke, thoroughly used up, totally worn out, and > loudly proclaiming “Wow! What a Ride!” - Hunter Thompson Daemeon C.M. > Reiydelle USA (+1) 415.501.0198 <%28%2B1%29%20415.501.0198> London (+44) > (0) 20 8144 9872 <%28%2B44%29%20%280%29%2020%208144%209872>* > > > > On Mon, Mar 16, 2015 at 8:41 PM, Saladi Naidu <naidusp2...@yahoo.com> > wrote: > > There are 3 different things we are talking here > > > > 1. SimpleStrategy vs. NetworkTopology matter when you have single DC vs. > Multiple DC's > > 2. In both cases you can specific replication factor, obviously in > SimpleStratgey case you dont mention DC whereas in NetworkTopology, you can > mentione mutiple options by each DC's replication requirements. > > 3. Now if your question is referred to single DC then even if your System > keyspace is SimpleStartegy and your user table is NetworkToplogy, it should > not matter and Table_Test will be created in all nodes > > 4. If your System_auth KS is set less than number of nodes, you will face > AUTH issues. > > > > Naidu Saladi > > > ------------------------------ > > *From:* 鄢来琼 <laiqiong....@gtafe.com> > *To:* "user@cassandra.apache.org" <user@cassandra.apache.org> > *Sent:* Monday, March 16, 2015 2:13 AM > *Subject:* Re: Is Table created in all the nodes if the default > consistency level used > > > > Hi Daemeon, > > > > Yes, I use “NetworkTopologyStrategy” strategy for “Table_test”, > > but “System keyspace” is Cassandra internal keyspace, its strategy is > localStrategy. > > So my question is how to guarantee “Table_test” is created in all the > nodes before any R/W opertions? > > > > Thanks. > > > > Peter > > > > > > > > *发件人**:* daemeon reiydelle [mailto:daeme...@gmail.com] > *发送时间**:* 2015年3月16日 14:35 > *收件人**:* user@cassandra.apache.org > *主题**:* Re: Is Table created in all the nodes if the default consistency > level used > > > > If you want to guarantee that the data is written to all nodes before the > code returns, then yes you have to use "consistency all". Otherwise there > is a small risk of outdated data being served if a node goes offline longer > than hints timeouts. > > Somewhat looser options that can assure multiple copies are written, as > you probably know, are quorum or a hard coded value. This applies to a > typical installation with a substantial number of nodes of course, not a > small 2-3 node cluster. > > I am curious why localStrategy when you have such concerns about data > consistency that you want to assure all nodes get data written. Can you > elaborate on your use case? > > > > > > > > > > > > * ....... “Life should not be a journey to the grave with the intention of > arriving safely in a pretty and well preserved body, but rather to skid in > broadside in a cloud of smoke, thoroughly used up, totally worn out, and > loudly proclaiming “Wow! What a Ride!” - Hunter Thompson Daemeon C.M. > Reiydelle USA (+1) 415.501.0198 <%28%2B1%29%20415.501.0198> London (+44) > (0) 20 8144 9872 <%28%2B44%29%20%280%29%2020%208144%209872>* > > > > On Sun, Mar 15, 2015 at 8:11 PM, 鄢来琼 <laiqiong....@gtafe.com> wrote: > > Could you tell me whether the meta data of the new table are build in all > the nodes after execute the following statement. > > > > *cassandra_session.execute_async(* > > *“““**CREATE TABLE Table_test(* > > * ID uuid,* > > * Time timestamp,* > > * Value double,* > > * Date timestamp,* > > * PRIMARY KEY ((ID,Date), Time)* > > *) WITH COMPACT STORAGE;* > > *”””* > > *)* > > > > As I know, the system keyspace is used to store the meta data, but the > strategy is localStrategy, which only store meta data of local node. > > So I want to know whether table is created in all the nodes, should I add > consistency_level setting to the above statement to make sure > > “create table” will be executed in all the nodes? > > Thanks. > > > > Peter > > > > > > > > >
