improve memory use and timeout defaults

patch by jbellis; reviewed by brandonwilliams for CASSANDRA-6059

CHANGES.txt

@@ -1,4 +1,5 @@
 2.0.2
+ * Improve memory use defaults (CASSANDRA-5069)
  * Make ThriftServer more easlly extensible (CASSANDRA-6058)
  * Remove Hadoop dependency from ITransportFactory (CASSANDRA-6062)
 Merged from 1.2:

NEWS.txt

@@ -13,6 +13,16 @@ restore snapshots created with the previous major version using the
 'sstableloader' tool. You can upgrade the file format of your snapshots
 using the provided 'sstableupgrade' tool.
 
+2.0.2
+=====
+
+Upgrading
+---------
+    - The default memtable allocation has changed from 1/3 of heap to 1/4
+      of heap.  Also, default (single-partition) read and write timeouts
+      have been reduced from 10s to 5s and 2s, respectively.
+
+
 2.0.0
 =====
 

conf/cassandra.yaml

@@ -460,11 +460,11 @@ compaction_preheat_key_cache: true
 # stream_throughput_outbound_megabits_per_sec: 200
 
 # How long the coordinator should wait for read operations to complete
-read_request_timeout_in_ms: 10000
+read_request_timeout_in_ms: 5000
 # How long the coordinator should wait for seq or index scans to complete
 range_request_timeout_in_ms: 10000
 # How long the coordinator should wait for writes to complete
-write_request_timeout_in_ms: 10000
+write_request_timeout_in_ms: 2000
 # How long a coordinator should continue to retry a CAS operation
 # that contends with other proposals for the same row
 cas_contention_timeout_in_ms: 1000

src/java/org/apache/cassandra/config/Config.java

@@ -56,7 +56,7 @@ public class Config
 
     public Long range_request_timeout_in_ms = new Long(10000);
 
-    public Long write_request_timeout_in_ms = new Long(10000);
+    public Long write_request_timeout_in_ms = new Long(2000);
 
     public Long cas_contention_timeout_in_ms = new Long(1000);
 

src/java/org/apache/cassandra/config/DatabaseDescriptor.java

@@ -249,7 +249,7 @@ public class DatabaseDescriptor
             conf.file_cache_size_in_mb = Math.min(512, (int) (Runtime.getRuntime().maxMemory() / (4 * 1048576)));
 
         if (conf.memtable_total_space_in_mb == null)
-            conf.memtable_total_space_in_mb = (int) (Runtime.getRuntime().maxMemory() / (3 * 1048576));
+            conf.memtable_total_space_in_mb = (int) (Runtime.getRuntime().maxMemory() / (4 * 1048576));
         if (conf.memtable_total_space_in_mb <= 0)
             throw new ConfigurationException("memtable_total_space_in_mb must be positive");
         logger.info("Global memtable threshold is enabled at {}MB", conf.memtable_total_space_in_mb);