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From Eric Stevens <migh...@gmail.com>
Subject Re: Is Table created in all the nodes if the default consistency level used
Date Mon, 16 Mar 2015 17:28:51 GMT
> Cassandra is used in a message process system.

> The table will be created at a fixed time each day.

Make sure you're keeping the total number of tables which exist at any
given time to a reasonable limit.  There is a fixed memory cost for each
table, and if you have too many tables you will produce memory pressure in
Cassandra.

On Mon, Mar 16, 2015 at 1:28 AM, 鄢来琼 <laiqiong.yan@gtafe.com> wrote:

>  Cassandra is used in a message process system.
>
> The table will be created at a fixed time each day.
>
> We want the table can be created before the message arrived.
>
> So I want to guarantee table is created in all the nodes.
>
>
>
> Peter
>
>
>
> *发件人:* 鄢来琼
> *发送时间:* 2015年3月16日 15:14
> *收件人:* user@cassandra.apache.org
> *主题:* 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:daemeonr@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 is a small risk of outdated data being served if a node goes offline longer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.yan@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
>
>
>
>
>

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