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Posted to issues@hive.apache.org by "Jesus Camacho Rodriguez (JIRA)" <ji...@apache.org> on 2018/02/28 18:03:00 UTC
[jira] [Updated] (HIVE-18825) Define ValidTxnList before starting
query optimization
[ https://issues.apache.org/jira/browse/HIVE-18825?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jesus Camacho Rodriguez updated HIVE-18825:
-------------------------------------------
Description:
Consider a set of tables used by a materialized view where inserts happened after the materialization was created. To compute incremental view maintenance, we need to be able to filter only new rows from those base tables. That can be done by inserting a filter operator with condition e.g. {{ROW__ID.transactionId < highwatermark and ROW__ID.transactionId NOT IN(<open txns>)}} on top of the MVs query definition and triggering the rewriting (which should in turn produce a partial rewriting). However, to do that, we need to have a value for {{ValidTxnList}} during query compilation so we know the snapshot that we are querying.
This patch aims to generate {{ValidTxnList}} before query optimization. There should not be any visible changes for end user.
was:
Consider a set of tables used by a materialized view where inserts happened after the materialization was created. To compute incremental view maintenance, we need to be able to filter only new rows from those base tables. That can be done by inserting a filter operator with condition e.g. {{ROW__ID.transactionId < highwatermark and ROW__ID.transactionId NOT IN(<open txns>)}} on top of the MVs query definition and triggering the rewriting (which should in turn produce a partial rewriting). However, to do that, we need to have a value for {{ValidTxnList}} during query compilation so we know the snapshot that we are querying.
This patch aims to generate {{ValidTxnList}} before query compilation. There should not be any visible changes for end user.
> Define ValidTxnList before starting query optimization
> ------------------------------------------------------
>
> Key: HIVE-18825
> URL: https://issues.apache.org/jira/browse/HIVE-18825
> Project: Hive
> Issue Type: Improvement
> Components: Transactions
> Affects Versions: 3.0.0
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Priority: Major
>
> Consider a set of tables used by a materialized view where inserts happened after the materialization was created. To compute incremental view maintenance, we need to be able to filter only new rows from those base tables. That can be done by inserting a filter operator with condition e.g. {{ROW__ID.transactionId < highwatermark and ROW__ID.transactionId NOT IN(<open txns>)}} on top of the MVs query definition and triggering the rewriting (which should in turn produce a partial rewriting). However, to do that, we need to have a value for {{ValidTxnList}} during query compilation so we know the snapshot that we are querying.
> This patch aims to generate {{ValidTxnList}} before query optimization. There should not be any visible changes for end user.
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