[jira] [Commented] (CASSANDRA-6692) AtomicBTreeColumns Improvements
[
https://issues.apache.org/jira/browse/CASSANDRA-6692?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13932634#comment-13932634
]
Jonathan Ellis commented on CASSANDRA-6692:
---
Strongly dislike this pattern:
{code}
if (updateF == null)
updateF = UpdateFunction.NoOp.instance();
{code}
Prefer not modifying parameters (making caller pass NoOp) and optionally adding
an assert to make it obvious. Will commit with that change.
AtomicBTreeColumns Improvements
---
Key: CASSANDRA-6692
URL: https://issues.apache.org/jira/browse/CASSANDRA-6692
Project: Cassandra
Issue Type: Improvement
Components: Core
Reporter: Benedict
Assignee: Benedict
Priority: Minor
Labels: easyfix, performance
Fix For: 2.1 beta2
Attachments: 6692.3.txt, 6692.fix, patch.txt
There are two improvements to make to the BTree code that should help:
1) It turns out Stack Allocation is more rubbish than we had hoped, and so
the fast route actually allocates garbage. It's unlikely this reduces
throughput, but the increased young-gen pressure is probably unwelcome. I
propose to remove the fast route for now.
2) It is not uncommon to race to perform an update, so that the new values
are actually out-of-date when we come to modify the tree. In this case the
update should recognise that the original (portion of) the tree has not been
modified, and simply return it, without allocating a new one.
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[jira] [Commented] (CASSANDRA-6692) AtomicBTreeColumns Improvements
[ https://issues.apache.org/jira/browse/CASSANDRA-6692?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13932641#comment-13932641 ] Benedict commented on CASSANDRA-6692: - Good point. AtomicBTreeColumns Improvements --- Key: CASSANDRA-6692 URL: https://issues.apache.org/jira/browse/CASSANDRA-6692 Project: Cassandra Issue Type: Improvement Components: Core Reporter: Benedict Assignee: Benedict Priority: Minor Labels: easyfix, performance Fix For: 2.1 beta2 Attachments: 6692.3.txt, 6692.fix, patch.txt There are two improvements to make to the BTree code that should help: 1) It turns out Stack Allocation is more rubbish than we had hoped, and so the fast route actually allocates garbage. It's unlikely this reduces throughput, but the increased young-gen pressure is probably unwelcome. I propose to remove the fast route for now. 2) It is not uncommon to race to perform an update, so that the new values are actually out-of-date when we come to modify the tree. In this case the update should recognise that the original (portion of) the tree has not been modified, and simply return it, without allocating a new one. -- This message was sent by Atlassian JIRA (v6.2#6252)
[jira] [Commented] (CASSANDRA-6692) AtomicBTreeColumns Improvements
[ https://issues.apache.org/jira/browse/CASSANDRA-6692?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13932660#comment-13932660 ] Jonathan Ellis commented on CASSANDRA-6692: --- committed AtomicBTreeColumns Improvements --- Key: CASSANDRA-6692 URL: https://issues.apache.org/jira/browse/CASSANDRA-6692 Project: Cassandra Issue Type: Improvement Components: Core Reporter: Benedict Assignee: Benedict Priority: Minor Labels: easyfix, performance Fix For: 2.1 beta2 Attachments: 6692.3.txt, 6692.fix, patch.txt There are two improvements to make to the BTree code that should help: 1) It turns out Stack Allocation is more rubbish than we had hoped, and so the fast route actually allocates garbage. It's unlikely this reduces throughput, but the increased young-gen pressure is probably unwelcome. I propose to remove the fast route for now. 2) It is not uncommon to race to perform an update, so that the new values are actually out-of-date when we come to modify the tree. In this case the update should recognise that the original (portion of) the tree has not been modified, and simply return it, without allocating a new one. -- This message was sent by Atlassian JIRA (v6.2#6252)
[jira] [Commented] (CASSANDRA-6692) AtomicBTreeColumns Improvements
[
https://issues.apache.org/jira/browse/CASSANDRA-6692?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13906400#comment-13906400
]
Aleksey Yeschenko commented on CASSANDRA-6692:
--
This seems to have broken a bunch of tests (getting NPE from isLeaf()).
For example,
{noformat}
[junit] Testcase:
testIndexUpdate(org.apache.cassandra.db.ColumnFamilyStoreTest): Caused an
ERROR
[junit] null
[junit] java.lang.NullPointerException
[junit] at org.apache.cassandra.utils.btree.BTree.isLeaf(BTree.java:302)
[junit] at
org.apache.cassandra.utils.btree.NodeBuilder.update(NodeBuilder.java:131)
[junit] at
org.apache.cassandra.utils.btree.Builder.update(Builder.java:74)
[junit] at org.apache.cassandra.utils.btree.BTree.update(BTree.java:157)
[junit] at
org.apache.cassandra.db.AtomicBTreeColumns.addAllWithSizeDelta(AtomicBTreeColumns.java:254)
[junit] at org.apache.cassandra.db.Memtable.put(Memtable.java:195)
[junit] at
org.apache.cassandra.db.ColumnFamilyStore.apply(ColumnFamilyStore.java:1096)
[junit] at org.apache.cassandra.db.Keyspace.apply(Keyspace.java:370)
[junit] at org.apache.cassandra.db.Keyspace.apply(Keyspace.java:328)
[junit] at org.apache.cassandra.db.Mutation.apply(Mutation.java:205)
[junit] at
org.apache.cassandra.db.ColumnFamilyStoreTest.testIndexUpdate(ColumnFamilyStoreTest.java:389)
{noformat}
AtomicBTreeColumns Improvements
---
Key: CASSANDRA-6692
URL: https://issues.apache.org/jira/browse/CASSANDRA-6692
Project: Cassandra
Issue Type: Improvement
Components: Core
Reporter: Benedict
Assignee: Benedict
Priority: Minor
Labels: easyfix, performance
Fix For: 2.1
There are two improvements to make to the BTree code that should help:
1) It turns out Stack Allocation is more rubbish than we had hoped, and so
the fast route actually allocates garbage. It's unlikely this reduces
throughput, but the increased young-gen pressure is probably unwelcome. I
propose to remove the fast route for now.
2) It is not uncommon to race to perform an update, so that the new values
are actually out-of-date when we come to modify the tree. In this case the
update should recognise that the original (portion of) the tree has not been
modified, and simply return it, without allocating a new one.
--
This message was sent by Atlassian JIRA
(v6.1.5#6160)
[jira] [Commented] (CASSANDRA-6692) AtomicBTreeColumns Improvements
[ https://issues.apache.org/jira/browse/CASSANDRA-6692?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13903667#comment-13903667 ] Benedict commented on CASSANDRA-6692: - Are you sure? It doesn't appear to be applied to trunk, and I can't see the commit message in my email history AtomicBTreeColumns Improvements --- Key: CASSANDRA-6692 URL: https://issues.apache.org/jira/browse/CASSANDRA-6692 Project: Cassandra Issue Type: Improvement Components: Core Reporter: Benedict Assignee: Benedict Priority: Minor Labels: easyfix, performance Fix For: 2.1 There are two improvements to make to the BTree code that should help: 1) It turns out Stack Allocation is more rubbish than we had hoped, and so the fast route actually allocates garbage. It's unlikely this reduces throughput, but the increased young-gen pressure is probably unwelcome. I propose to remove the fast route for now. 2) It is not uncommon to race to perform an update, so that the new values are actually out-of-date when we come to modify the tree. In this case the update should recognise that the original (portion of) the tree has not been modified, and simply return it, without allocating a new one. -- This message was sent by Atlassian JIRA (v6.1.5#6160)
[jira] [Commented] (CASSANDRA-6692) AtomicBTreeColumns Improvements
[ https://issues.apache.org/jira/browse/CASSANDRA-6692?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13903714#comment-13903714 ] Jonathan Ellis commented on CASSANDRA-6692: --- re-committed and pushed this time. AtomicBTreeColumns Improvements --- Key: CASSANDRA-6692 URL: https://issues.apache.org/jira/browse/CASSANDRA-6692 Project: Cassandra Issue Type: Improvement Components: Core Reporter: Benedict Assignee: Benedict Priority: Minor Labels: easyfix, performance Fix For: 2.1 There are two improvements to make to the BTree code that should help: 1) It turns out Stack Allocation is more rubbish than we had hoped, and so the fast route actually allocates garbage. It's unlikely this reduces throughput, but the increased young-gen pressure is probably unwelcome. I propose to remove the fast route for now. 2) It is not uncommon to race to perform an update, so that the new values are actually out-of-date when we come to modify the tree. In this case the update should recognise that the original (portion of) the tree has not been modified, and simply return it, without allocating a new one. -- This message was sent by Atlassian JIRA (v6.1.5#6160)
