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From: java8964 java8964 <java8964@hotmail.com>
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Subject: RE: Questions related to the data in SSTable files
Date: Tue, 22 Oct 2013 20:17:06 -0400
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Any way I can verify how often the system being "repaired"? I can ask anoth=
er group who maintain the Cassandra cluster. But do you mean that even the =
failed writes will be stored in the SSTable files?=20
I thought the Cassandra will use different storage to store that kind of da=
ta=2C as the regular good data in memtable=2C then in the SSTable files.
Yong

Date: Tue=2C 22 Oct 2013 14:50:07 -0700
Subject: Re: Questions related to the data in SSTable files
From: rcoli@eventbrite.com
To: user@cassandra.apache.org

On Tue=2C Oct 22=2C 2013 at 2:29 PM=2C java8964 java8964 <java8964@hotmail.=
com> wrote:
=0A=
=0A=
=0A=
=0A=
1) In the data of full snapshot=2C I see more than 10% of duplication data.=
 What I mean duplication is that there are event_activities with the same (=
entity_1_id=2C entity_2_id=2C entity_3_id=2C entity_4_id=2C created_on_time=
stamp=2C column_timestamp). I am surprised to see the high level duplicatio=
n data=2C especially even adding with the column_timestamp. As my understan=
ding=2C the column_timestamp is provided from the client when Cassandra sto=
re the column in the row key data. So if there are some small amount of dup=
lication=2C I can explain as application bug=2C or duplication comes from t=
he replication. But more than 10% is too much to explain this way.=0A=

Have you run "repair"? Do you regularly have hinted handoff kicking in due =
to down nodes or dropped messages=2C such that failed writes are re-deliver=
ed as hints?=0A=
 =3DRob
 		 	   		  =

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<body class=3D'hmmessage'><div dir=3D'ltr'>Any way I can verify how often t=
he system being "repaired"? I can ask another group who maintain the Cassan=
dra cluster. But do you mean that even the failed writes will be stored in =
the SSTable files?&nbsp=3B<div><br></div><div>I thought the Cassandra will =
use different storage to store that kind of data=2C as the regular good dat=
a in memtable=2C then in the SSTable files.</div><div><br></div><div>Yong<b=
r><br><div><hr id=3D"stopSpelling">Date: Tue=2C 22 Oct 2013 14:50:07 -0700<=
br>Subject: Re: Questions related to the data in SSTable files<br>From: rco=
li@eventbrite.com<br>To: user@cassandra.apache.org<br><br><div dir=3D"ltr">=
On Tue=2C Oct 22=2C 2013 at 2:29 PM=2C java8964 java8964 <span dir=3D"ltr">=
&lt=3B<a href=3D"mailto:java8964@hotmail.com" target=3D"_blank">java8964@ho=
tmail.com</a>&gt=3B</span> wrote:<br><div class=3D"ecxgmail_extra"><div cla=
ss=3D"ecxgmail_quote">=0A=
<blockquote class=3D"ecxgmail_quote" style=3D"border-left:1px #ccc solid=3B=
padding-left:1ex=3B">=0A=
=0A=
=0A=
<div><div dir=3D"ltr"><div>1) In the data of full snapshot=2C I see more th=
an 10% of duplication data. What I mean duplication is that there are event=
_activities with the same (entity_1_id=2C entity_2_id=2C entity_3_id=2C ent=
ity_4_id=2C created_on_timestamp=2C column_timestamp). I am surprised to se=
e the high level duplication data=2C especially even adding with the column=
_timestamp. As my understanding=2C the column_timestamp is provided from th=
e client when Cassandra store the column in the row key data. So if there a=
re some small amount of duplication=2C I can explain as application bug=2C =
or duplication comes from the replication. But more than 10% is too much to=
 explain this way.</div>=0A=
</div></div></blockquote><div><br></div><div>Have you run "repair"? Do you =
regularly have hinted handoff kicking in due to down nodes or dropped messa=
ges=2C such that failed writes are re-delivered as hints?</div>=0A=
<div>&nbsp=3B</div><div>=3DRob</div><div><br></div></div></div></div></div>=
</div> 		 	   		  </div></body>
</html>=

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