ignite-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Konstantin Orlov (Jira)" <j...@apache.org>
Subject [jira] [Commented] (IGNITE-13667) Add schema columns relocation table to map from user order to system order
Date Tue, 06 Jul 2021 12:49:00 GMT

    [ https://issues.apache.org/jira/browse/IGNITE-13667?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17375706#comment-17375706
] 

Konstantin Orlov commented on IGNITE-13667:
-------------------------------------------

 [~amashenkov], actually it _does_ guarantee the order.

[Here|https://stackoverflow.com/questions/11737232/column-order-in-select-statement-guaranteed]
is a good explanation with references to the SQL standard.

> Add schema columns relocation table to map from user order to system order
> --------------------------------------------------------------------------
>
>                 Key: IGNITE-13667
>                 URL: https://issues.apache.org/jira/browse/IGNITE-13667
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Alexey Goncharuk
>            Priority: Minor
>              Labels: iep-54, ignite-3
>
> When a schema is defined, the key chunk columns and value chunk columns are sorted so
that fixlen columns go first and varlen columns go second, so the sorted column order differs
from the order of the user-defined columns.
> We need to add a simple relocation table which is a permutation of indices {{[0..n)}},
so that an internal column order for user index {{n}} is {{relocationTbl[n]}}.
> NB: the tuple assembler will still need to access the internal sorted order for proper
tuple assembly.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

Mime
View raw message