how to avoid range ghosts?
Hi, What is the recommended way to avoid range ghost in using get_range()?In my case, order of the key is not problem. It seems valid to use random :start_key in every query, but i'm new to cassandra and do not know if it'srecommended or not. I use Cassandra 1.1.4 and ruby client. Range ghosts happens when oneprocess keeps on inserting data while other process get_range and deletethem. thanks in advance,satoshi
Re: MBean cassandra.db.CompactionManager TotalBytesCompacted counts backwards
I have not looked at this JMX object in a while, however the compaction manager can support multiple threads. Also it moves from 0-filesize each time it has to compact a set of files. That is more useful for showing current progress rather then lifetime history. On Fri, Oct 5, 2012 at 7:27 PM, Bryan Talbot btal...@aeriagames.com wrote: I've recently added compaction rate (in bytes / second) to my monitors for cassandra and am seeing some odd values. I wasn't expecting the values for TotalBytesCompacted to sometimes decrease from one reading to the next. It seems that the value should be monotonically increasing while a server is running -- obviously it would start again at 0 when the server is restarted or if the counter rolls over (unlikely for a 64 bit long). Below are two samples taken 60 seconds apart: the value decreased by 2,954,369,012 between the two readings. reported_metric=[timestamp:1349476449, status:200, request:[mbean:org.apache.cassandra.db:type=CompactionManager, attribute:TotalBytesCompacted, type:read], value:7548675470069] previous_metric=[timestamp:1349476389, status:200, request:[mbean:org.apache.cassandra.db:type=CompactionManager, attribute:TotalBytesCompacted, type:read], value:7551629839081] I briefly looked at the code for CompactionManager and a few related classes and don't see anyplace that is performing subtraction explicitly; however, there are many additions of signed long values that are not validated and could conceivably contain a negative value thus causing the totalBytesCompacted to decrease. It's interesting to note that the all of the differences I've seen so far are more than the overflow value of a signed 32 bit value. The OS (CentOS 5.7) and sun java vm (1.6.0_29) are both 64 bit. JNA is enabled. Is this expected and normal? If so, what is the correct interpretation of this metric? I'm seeing the negatives values a few times per hour when reading it once every 60 seconds. -Bryan
Re: how to avoid range ghosts?
Read this: http://wiki.apache.org/cassandra/FAQ#range_ghosts Then say this to yourself: http://cn1.kaboodle.com/img/b/0/0/196/4/C1xHoQAAAZZL9w/ghostbusters-logo-i-aint-afraid-of-no-ghost-pinback-button-1.25-pin-badge.jpg?v=1320511953000 On Sun, Oct 7, 2012 at 4:15 AM, Satoshi Yamada bigtvioletb...@yahoo.co.jpwrote: Hi, What is the recommended way to avoid range ghost in using get_range()? In my case, order of the key is not problem. It seems valid to use random :start_key in every query, but i'm new to cassandra and do not know if it's recommended or not. I use Cassandra 1.1.4 and ruby client. Range ghosts happens when one process keeps on inserting data while other process get_range and delete them. thanks in advance, satoshi
Re: cql3 and cli composites columns
Thanks Aaron,
I don't understand what is the cli equivalent of:
CREATE TABLE timeline (
user_id varchar,
tweet_id bigint,
author varchar,
body varchar,
PRIMARY KEY (user_id, tweet_id)
);
2012/10/3 aaron morton aa...@thelastpickle.com
If it's just a printing issue it's really minor though
I would guess because timeline CF has defined columns and line CF does
not.
All cqlsh knows is that every column name has two parts, it does not know
what the column names will be. The difference between a static and dynamic
CF.
Hope that helps.
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 2/10/2012, at 10:37 PM, Cyril Auburtin cyril.aubur...@gmail.com
wrote:
I wanted to know why the highlighted sections below are printed
differently, the 2 column families are the same
Key Validation Class: org.apache.cassandra.db.marshal.UTF8Type
Default column value validator: org.apache.cassandra.db.marshal.UTF8Type
Columns sorted by:
org.apache.cassandra.db.marshal.CompositeType(org.apache.cassandra.db.marshal.LongType,org.apache.cassandra.db.marshal.UTF8Type)
, except one is created from cql3:
If it's just a printing issue it's really minor though
on cql3:
CREATE TABLE timeline (
... user_id varchar,
... tweet_id bigint,
... author varchar,
... body varchar,
... PRIMARY KEY (user_id, tweet_id)
... );
INSERT INTO timeline (user_id, tweet_id, author, body) VALUES ('gmason',
1765, 'phenry', 'Give me liberty or give me death');
on CLI:
create column family line with comparator = 'CompositeType(LongType,
UTF8Type)' AND key_validation_class=UTF8Type AND default_validation_class =
UTF8Type;
set line['dude']['1545:ok'] = '1';
set line['dude']['1545:ok1'] = '1';
list timeline;
RowKey: gmason
= (column=1765:author, value=phenry, timestamp=1349161331154000)
= (column=1765:body, value=Give me liberty or give me death,
timestamp=1349161331154001)
list line;
RowKey: dude
= (column=1545:ok, value=1, timestamp=1349162658714000)
= (column=1545:ok1, value=1, timestamp=1349162638658000)
on cql3:
select * from timeline;
user_id | tweet_id | author | body
-+--++--
gmason | 1765 | phenry | Give me liberty or give me death
select * from line;
key | column1 | column2 | value
--+-+-+---
dude |1545 | ok | 1
dude |1545 | ok1 | 1
ps: I have tried
update column family line with comparator = 'CompositeType(LongType,
UTF8Type)' AND key_validation_class=UTF8Type AND column_metadata = [
{column_name: tweet_id, validation_class: LongType}
{column_name: author, validation_class: UTF8Type}
{column_name: body, validation_class: UTF8Type}
];
for the CF line but it gives:
java.lang.RuntimeException:
org.apache.cassandra.db.marshal.MarshalException: unable to make long from
'tweet_id'
Re: cql3 and cli composites columns
Once you have created the CF from cqlsh, switch over to cassandra-cli
and run describe schema. It will show you the schema for all your
column families in syntax that can be passed back into cassandra-cli
to create them.
The cassandr-cli syntax that you are looking for is probably the and
column_metadata = section.
-Tupshin
On Sun, Oct 7, 2012 at 4:43 PM, Cyril Auburtin cyril.aubur...@gmail.com wrote:
Thanks Aaron,
I don't understand what is the cli equivalent of:
CREATE TABLE timeline (
user_id varchar,
tweet_id bigint,
author varchar,
body varchar,
PRIMARY KEY (user_id, tweet_id)
);
2012/10/3 aaron morton aa...@thelastpickle.com
If it's just a printing issue it's really minor though
I would guess because timeline CF has defined columns and line CF does
not.
All cqlsh knows is that every column name has two parts, it does not know
what the column names will be. The difference between a static and dynamic
CF.
Hope that helps.
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 2/10/2012, at 10:37 PM, Cyril Auburtin cyril.aubur...@gmail.com
wrote:
I wanted to know why the highlighted sections below are printed
differently, the 2 column families are the same
Key Validation Class: org.apache.cassandra.db.marshal.UTF8Type
Default column value validator: org.apache.cassandra.db.marshal.UTF8Type
Columns sorted by:
org.apache.cassandra.db.marshal.CompositeType(org.apache.cassandra.db.marshal.LongType,org.apache.cassandra.db.marshal.UTF8Type)
, except one is created from cql3:
If it's just a printing issue it's really minor though
on cql3:
CREATE TABLE timeline (
... user_id varchar,
... tweet_id bigint,
... author varchar,
... body varchar,
... PRIMARY KEY (user_id, tweet_id)
... );
INSERT INTO timeline (user_id, tweet_id, author, body) VALUES ('gmason',
1765, 'phenry', 'Give me liberty or give me death');
on CLI:
create column family line with comparator = 'CompositeType(LongType,
UTF8Type)' AND key_validation_class=UTF8Type AND default_validation_class =
UTF8Type;
set line['dude']['1545:ok'] = '1';
set line['dude']['1545:ok1'] = '1';
list timeline;
RowKey: gmason
= (column=1765:author, value=phenry, timestamp=1349161331154000)
= (column=1765:body, value=Give me liberty or give me death,
timestamp=1349161331154001)
list line;
RowKey: dude
= (column=1545:ok, value=1, timestamp=1349162658714000)
= (column=1545:ok1, value=1, timestamp=1349162638658000)
on cql3:
select * from timeline;
user_id | tweet_id | author | body
-+--++--
gmason | 1765 | phenry | Give me liberty or give me death
select * from line;
key | column1 | column2 | value
--+-+-+---
dude |1545 | ok | 1
dude |1545 | ok1 | 1
ps: I have tried
update column family line with comparator = 'CompositeType(LongType,
UTF8Type)' AND key_validation_class=UTF8Type AND column_metadata = [
{column_name: tweet_id, validation_class: LongType}
{column_name: author, validation_class: UTF8Type}
{column_name: body, validation_class: UTF8Type}
];
for the CF line but it gives:
java.lang.RuntimeException:
org.apache.cassandra.db.marshal.MarshalException: unable to make long from
'tweet_id'
