Re: Indexes Fragmentation

[Arthur Zubarev <ar...@aol.com>]

Hello Rob,
    
    I now see I had misspelled the word tall for toll, anyways, if I    understood correctly, your reply implies there is no impact    whatsoever and there is no need to defrug indexes of the frequently    changing columns. 

Am I right?
 
Thank you!

 

Regards,

Arthur

 

---- Original Message ----
From: Robert Coli <rc...@eventbrite.com>
To: user <us...@cassandra.apache.org>
Sent: Mon, Sep 29, 2014 8:01 pm
Subject: Re: Indexes Fragmentation



On Sun, Sep 28, 2014 at 9:49 AM, Arthur Zubarev <ar...@aol.com> wrote:
There are 200+ times more updates and 50x inserts than analytical loads.

In Cassandra to just be able to query (in CQL) on a column I have to have an index, the question is what tall the fragmentation coming from the frequent updates and inserts has on a CF? Do I also need to manually defrug? 




You have appeared to have just asked if maintaing indexes which have a high rate of change in a log structured database with immutable data files is likely to be more performant than maintaining them in a database with modify-in-place semantics.


"No."


=Rob

Re: Indexes Fragmentation

[Robert Coli <rc...@eventbrite.com>]

On Fri, Oct 3, 2014 at 6:03 PM, Arthur Zubarev <ar...@aol.com>
wrote:

> I now see I had misspelled the word tall for toll, anyways, if I
> understood correctly, your reply implies there is no impact whatsoever and
> there is no need to defrug indexes of the frequently changing columns.
>

"Cases with lots of secondary indexes which have a lot of churn are not
well suited for a database with immutable datafiles which wants to be
accessed by Primary Key."

The fragmentation is really bad, because the data files are immutable and
you have a lot of churn. Probably don't do it?

=Rob