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From Serega Sheypak <serega.shey...@gmail.com>
Subject Re: Show last 10 (100/1000) events
Date Wed, 14 Jan 2015 19:18:16 GMT
no it would be 10/100/10000
10000 is absolute limit. I understand that simple threadsafe java
collection can handle this.

2015-01-14 22:17 GMT+03:00 Serega Sheypak <serega.sheypak@gmail.com>:

> Ok, I got it, thanks.
>
> 2015-01-14 19:22 GMT+03:00 Wilm Schumacher <wilm.schumacher@gmail.com>:
>
>> Will the number of "last" will be much larger than 10 (100/1000)?
>>
>> If not, then I wouldn't bother with a real database after all and would
>> hold the data in RAM.
>>
>> Either:
>> * in an object in your "gateway" to hbase. E.g. simple java Array list
>> in your java server which serves the api to the web servers. This would
>> be super easy and super fast
>>
>> Or:
>> * in-memory-db like redis if you haven't something like above
>>
>> Or you redisgn your datamodel to something timestamp based. Then it's a
>> scan.
>>
>> Best wishes,
>>
>> Wilm
>>
>> Am 14.01.2015 um 16:51 schrieb Serega Sheypak:
>> > Hi, I have event-processing system which uses hbase + a pack of tomcat
>> > web-apps as front-end.
>> > tomcat web-apps are similar and used for front-end load-balancing.
>> > tomcat apps write events to hbase.
>> >
>> > What is good pattern to show last 10/100/1000 events?
>> > events table schema is:
>> > row_key=user_id
>> > each user_id has 128 versions. So I keep history for the last 128 user
>> > events.
>> >
>> > There is no way to get last events, I can get last event only for
>> concrete
>> > user.
>> >
>> > I had an idea to create separate table named 'last_events'
>> > and force all tomcats write there copy of event with the same key and
>> set
>> > versions count to 1000.
>> > HBase would automatically delete old events.
>> > Drawbacks are:
>> > 1. x2 traffic
>> > 2. x2 write ops on hbase to single region
>> >
>> > Solution is bad.
>> > Are they any good patterns to resolve such problem. The other option is
>> to
>> > use some kind of memcache or stuff like that.
>> >
>>
>>
>

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