[jira] [Resolved] (CASSANDRA-9272) Atomic Batch Statements Fail to Execute on Some Coordinators

["Carl Yeksigian (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-9272?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Carl Yeksigian resolved CASSANDRA-9272.
---------------------------------------
       Resolution: Not A Problem
    Reproduced In: 2.0.14, 2.0.6  (was: 2.0.6, 2.0.14)

This is working as designed.

For DC2, we allow writing to the local node because it is a single-node DC. Otherwise, at least 1 node in the local DC which is not the localhost and is up according to the failure detector will be used. Since there are no nodes in DC1 which satisfy those conditions, we throw an unavailable exception.

The only way to insert into DC1 with 1 node down is to use consistency level {{ANY}}, which allows using the localhost if there are no other nodes in the local DC.

> Atomic Batch Statements Fail to Execute on Some Coordinators
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-9272
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9272
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>         Environment: Operating System: Red Hat Enterprise Linux Server release 6.5 (Santiago) |
> Cassandra and CQL: [cqlsh 4.1.1 | Cassandra 2.0.14 | CQL spec 3.1.1 | Thrift protocol 19.39.0] |
> JVM vendor/version: Java HotSpot(TM) 64-Bit Server VM/1.7.0_79 (Oracle Java) |
> Using PropertyFileSnitch to define cluster topology.
>            Reporter: Jared Gray
>            Assignee: Carl Yeksigian
>             Fix For: 2.0.x
>
>
> Install and configure a three-node Cassandra cluster spread across two data centers (DCs). Place two Cassandra instances in DC1 and one Cassandra instance in DC2. (We have designated one node as a seed in each data center.)
> Gracefully shut down any one Cassandra instance in DC1. This can be done by running 'kill <process_id>' in Linux.
> Open a CQL Shell connection to the remaining node in DC1.
> Create the following keyspace: {{CREATE KEYSPACE batch_test WITH replication = \{'class': 'NetworkTopologyStrategy', 'DC1': '2', 'DC2':'1'\};}}
> Create the following table: {{CREATE TABLE batch_test.batch_table ( partition_key TEXT PRIMARY KEY );}}
> Execute the following atomic batch query: {{BEGIN BATCH INSERT INTO batch_test.batch_table (partition_key) VALUES ('a'); INSERT INTO batch_test.batch_table (partition_key) VALUES ('b'); APPLY BATCH}};
> Observe an availability-related error, despite a sufficient number of nodes available to service the query. The trace below shows sample results from our cluster:
> DC1
> ----
> {noformat}
> cqlsh> CONSISTENCY
> Current consistency level is ONE.
> cqlsh> BEGIN BATCH INSERT INTO batch_test.batch_table (partition_key) VALUES ('a'); INSERT INTO batch_test.batch_table (partition_key) VALUES ('b'); APPLY BATCH;
> Unable to complete request: one or more nodes were unavailable.
> cqlsh> CONSISTENCY QUORUM
> Consistency level set to QUORUM.
> cqlsh> BEGIN BATCH INSERT INTO batch_test.batch_table (partition_key) VALUES ('a'); INSERT INTO batch_test.batch_table (partition_key) VALUES ('b'); APPLY BATCH;
> Unable to complete request: one or more nodes were unavailable.
> cqlsh> BEGIN UNLOGGED BATCH INSERT INTO batch_test.batch_table (partition_key) VALUES ('a'); INSERT INTO batch_test.batch_table (partition_key) VALUES ('b'); APPLY BATCH;
> cqlsh>
> {noformat}
> Note: an UNLOGGED BATCH executes successfully. A regular BATCH also executes successfully if it only contains one INSERT query.
> We now show a similar trace using a CQL Shell connected to the Cassandra instance in DC2:
> DC2
> ---
> {noformat}
> cqlsh> CONSISTENCY
> Current consistency level is ONE.
> cqlsh> BEGIN BATCH INSERT INTO batch_test.batch_table (partition_key) VALUES ('a'); INSERT INTO batch_test.batch_table (partition_key) VALUES ('b'); APPLY BATCH;
> cqlsh> CONSISTENCY QUORUM
> Consistency level set to QUORUM.
> cqlsh> BEGIN BATCH INSERT INTO batch_test.batch_table (partition_key) VALUES ('a'); INSERT INTO batch_test.batch_table (partition_key) VALUES ('b'); APPLY BATCH;
> cqlsh> BEGIN UNLOGGED BATCH INSERT INTO batch_test.batch_table (partition_key) VALUES ('a'); INSERT INTO batch_test.batch_table (partition_key) VALUES ('b'); APPLY BATCH;
> cqlsh>
> {noformat}
> All queries execute successfully using the DC2 Cassandra instance as a coordinator.



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