sstable processing times

[James A. Robinson]

Hi folks,

I'm running a job on an offline node to test how long it takes to run
sstablesplit several large sstable.

I'm a bit dismayed to see it took about 22 hours to process a 1.5
gigabyte sstable!  I worry about the 32 gigabyte sstable that is my
ultimate target to split.

This is running on an otherwise unloaded Linux 3.10.0 CentOS 7 server
with 4 cpus and 24 gigabytes of ram.  Cassandra 3.11.0 and OpenJDK
1.8.0_252 are the installed versions of the software.

The machine isn't very busy itself, it looks as though java is only
making use of 1 of the 4 processors, and it's not using much of the
available 24 gigabytes of memory either, all the memory usage is in
the linux buffer cache, which I guess makes sense if it's just working
on these large files w/o needing to do a lot of heavy computation on
what it reads from them.

When you folks run sstablesplit, do you provide specific
CASSANDRA_INCLUDE settings to increase its performance?

Jim

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Re: reverse paging state

[Alex Ott]

Hi

for that version of the driver there is no build-in functionality for the
backward paging, although it's doable:
https://stackoverflow.com/questions/50168236/cassandra-pagination-inside-partition/50172052#50172052

for driver 4.9.0 there is a wrapper class that emultates random paging,
with tradeoff for performance:
https://docs.datastax.com/en/developer/java-driver/4.9/manual/core/paging/#offset-queries

On Fri, Oct 23, 2020 at 10:00 AM Manu Chadha 
wrote:

> In Java driver 3.4.0, how does one revert the order of paging? I want to
> implement a “Back” button but I can’t figure out from the API docs if/how I
> can make Cassandra (via the Java driver) search backwards.
>
>
>
> https://docs.datastax.com/en/drivers/java/3.4/
>
>
>
> The code I have written currently is
>
>
>
> session.execute(whereClause
>   .setFetchSize(fetchSize)
>
>   .setPagingState(pagingState))
>
>
>
> Thanks
>
> Manu
>
> Sent from Mail  for
> Windows 10
>
>
>


-- 
With best wishes,Alex Ott
http://alexott.net/
Twitter: alexott_en (English), alexott (Russian)

reverse paging state

[Manu Chadha]

In Java driver 3.4.0, how does one revert the order of paging? I want to 
implement a “Back” button but I can’t figure out from the API docs if/how I can 
make Cassandra (via the Java driver) search backwards.

https://docs.datastax.com/en/drivers/java/3.4/

The code I have written currently is


session.execute(whereClause
  .setFetchSize(fetchSize)

  .setPagingState(pagingState))


Thanks
Manu
Sent from Mail for Windows 10