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https://issues.apache.org/jira/browse/CASSANDRA-9272?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14540537#comment-14540537
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Jared Gray commented on CASSANDRA-9272:
---------------------------------------
Does this mean that the maximum number of tolerable replica failures using
QUORUM consistency should be:
min(n - floor(n/2+1), k - 2)
where n is the total number of replicas and k is the minimum number of replicas
present in any data center containing replicas, assuming k >=2?
> 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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