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Posted to issues-all@impala.apache.org by "Zoltán Borók-Nagy (Jira)" <ji...@apache.org> on 2020/06/15 16:21:00 UTC
[jira] [Updated] (IMPALA-9859) Milestone 4: Read updated tables
[ https://issues.apache.org/jira/browse/IMPALA-9859?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Zoltán Borók-Nagy updated IMPALA-9859:
--------------------------------------
Description:
Hive ACID supports row-level DELETE and UPDATE operatations on a table. It achieves it via assigning a unique row-id for each row, and maintinaining two sets of files in a table. The first set is in the delta directories, they contain the INSERTed rows. The second set of files are in the delete-delta directories, they contain the DELETEd rows.
_Note: UPDATE operations are implemented via DELETE+INSERT._
In the filesystem it looks like e.g.:
{noformat}
full_acid/delta_0000001_0000001_0000/0000_0
full_acid/delete_delta_0000002_0000002_0000/0000_0
{noformat}
During scanning we need to return INSERTed rows minus DELETEd rows. One way of doing that is to create an ANTI JOIN between INSERT and DELETE events.
was:
Hive ACID supports row-level DELETE and UPDATE operatations on a table. It achieves it via assigning a unique row-id for each row, and maintinaining two sets of files in a table. The first set is in the delta directories, they contain the INSERTed rows. The second set of files are in the delete-delta directories, they contain the DELETEd rows.
_Note: UPDATE operations are implemented via DELETE+INSERT._
In the filesystem it looks like e.g.:
{noformat}
full_acid/delta_0000001_0000001_0000/0000_0
full_acid/delete_delta_0000002_0000002_0000/0000_0
{noformat}
During scanning we need to return INSERTed rows minus DELETEd rows. One way of doing that is to create an ANTI JOIN between INSERT and DELETE events.
> Milestone 4: Read updated tables
> --------------------------------
>
> Key: IMPALA-9859
> URL: https://issues.apache.org/jira/browse/IMPALA-9859
> Project: IMPALA
> Issue Type: Sub-task
> Reporter: Zoltán Borók-Nagy
> Priority: Major
>
> Hive ACID supports row-level DELETE and UPDATE operatations on a table. It achieves it via assigning a unique row-id for each row, and maintinaining two sets of files in a table. The first set is in the delta directories, they contain the INSERTed rows. The second set of files are in the delete-delta directories, they contain the DELETEd rows.
> _Note: UPDATE operations are implemented via DELETE+INSERT._
> In the filesystem it looks like e.g.:
> {noformat}
> full_acid/delta_0000001_0000001_0000/0000_0
> full_acid/delete_delta_0000002_0000002_0000/0000_0
> {noformat}
> During scanning we need to return INSERTed rows minus DELETEd rows. One way of doing that is to create an ANTI JOIN between INSERT and DELETE events.
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