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Posted to issues@ignite.apache.org by "Aleksey Plekhanov (Jira)" <ji...@apache.org> on 2021/11/23 18:04:00 UTC
[jira] [Comment Edited] (IGNITE-13179) Calcite integration. Fix traits at the IgniteLimit
[ https://issues.apache.org/jira/browse/IGNITE-13179?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17448059#comment-17448059 ]
Aleksey Plekhanov edited comment on IGNITE-13179 at 11/23/21, 6:03 PM:
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[~korlov], first problem (distribution trait propagation) was already resolved by IGNITE-14973.
What about:
{quote}Also Limit must be propogated (copied) under Exchange to reduce unnecessary fetches.
{quote}
I'm not sure it will be very efficient since we already request the next batches of rows only until the limit is reached, so the only overhead here is the buffer size. But we can also make one more optimization: requests from {{LimitNode}} source no more than {{limit}} rows (currently we request the same amount of rows as requested by downstream). WDYT?
I've raised a pull request to show what I mean.
was (Author: alex_pl):
[~korlov], first problem (distribution trait propagation) was already resolved by IGNITE-14973.
What about:
{quote}Also Limit must be propogated (copied) under Exchange to reduce unnecessary fetches.
{quote}
I'm not sure it will be very efficient since we already request the next batches of rows only until the limit is reached, so the only overhead here is the buffer size. But we can also make one more optimization: requests from {{LimitNode}} source no more than {{limit}} rows (currently we request the same amount of rows as requested by downstream). WDYT?
> Calcite integration. Fix traits at the IgniteLimit
> --------------------------------------------------
>
> Key: IGNITE-13179
> URL: https://issues.apache.org/jira/browse/IGNITE-13179
> Project: Ignite
> Issue Type: Improvement
> Reporter: Taras Ledkov
> Assignee: Konstantin Orlov
> Priority: Major
> Labels: calcite2-required, calcite3-required
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Current implementation of {{IgniteLimit}} doesn't support distribution trait propagation.
> Limit must require singleton distribution.
> Now we cannot reproduce invalid behavior (see IGNITE-12819) and IgniteLimit isn't placed under the Exchange node.
> Also Limit must be propogated (copied) under Exchange to reduce unnecessary fetches.
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