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https://issues.apache.org/jira/browse/HBASE-13099?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14338032#comment-14338032
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Lars Hofhansl edited comment on HBASE-13099 at 2/26/15 7:06 AM:
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That's what small scans do (in a nutshell), when they are not small :)
That does mean that at every 1mb chunk we need to reseek all
\{region|store|storeFile\}Scanners. I.e. the server state allows us to avoid
the expensive seeking each RPC. Maybe with 1mb chunks it does not matter. (but
you can pull 1mb over 1ge in < 10ms, which is less then the seek time of an
HDD).
Some of the chunking logic we get with HBASE-12976.
was (Author: lhofhansl):
That's what small scans do (in a nutshell), when they are not small :)
That does mean that at every 1mb chunk we need to reseek are
{region|store|storeFile}Scanners. I.e. the server state allows us to avoid the
expensive seeking each RPC. Maybe with 1mb chunks it does not matter. (but you
can pull 1mb over 1ge in < 10ms, which is less then the seek time of an HDD).
Some of the chunking logic we get with HBASE-12976.
> Scans as in DynamoDB
> --------------------
>
> Key: HBASE-13099
> URL: https://issues.apache.org/jira/browse/HBASE-13099
> Project: HBase
> Issue Type: Brainstorming
> Components: Client, regionserver
> Reporter: Nicolas Liochon
>
> cc: [[email protected]] - as discussed offline.
> DynamoDB has a very simple way to manage scans server side:
> ??citation??
> The data returned from a Query or Scan operation is limited to 1 MB; this
> means that if you scan a table that has more than 1 MB of data, you'll need
> to perform another Scan operation to continue to the next 1 MB of data in the
> table.
> If you query or scan for specific attributes that match values that amount to
> more than 1 MB of data, you'll need to perform another Query or Scan request
> for the next 1 MB of data. To do this, take the LastEvaluatedKey value from
> the previous request, and use that value as the ExclusiveStartKey in the next
> request. This will let you progressively query or scan for new data in 1 MB
> increments.
> When the entire result set from a Query or Scan has been processed, the
> LastEvaluatedKey is null. This indicates that the result set is complete
> (i.e. the operation processed the “last page” of data).
> ??citation??
> This means that there is no state server side: the work is done client side.
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