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https://issues.apache.org/jira/browse/HIVE-25779?focusedWorklogId=792783&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-792783
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ASF GitHub Bot logged work on HIVE-25779:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 19/Jul/22 15:59
Start Date: 19/Jul/22 15:59
Worklog Time Spent: 10m
Work Description: saihemanth-cloudera commented on code in PR #3221:
URL: https://github.com/apache/hive/pull/3221#discussion_r924689709
##########
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java:
##########
@@ -5322,16 +5380,25 @@ private void copyMSD(MStorageDescriptor newSd,
MStorageDescriptor oldSd) {
oldSd.setCD(newSd.getCD());
}
}
+ // If the serde info of the old SD != the serde info of the new one,
+ // then we set the serde info of the old SD as the new serde info.
+ SerDeInfo oldSerDeInfo = null;
+ SerDeInfo newSerDeInfo = null;
+ try {
+ oldSerDeInfo = convertToSerDeInfo(oldSd.getSerDeInfo(), true);
+ newSerDeInfo = convertToSerDeInfo(newSd.getSerDeInfo(), true);
+ } catch (MetaException e) {
+ LOG.debug("convertToSerDeInfo shouldn't throw MetaException when
allowNull is set to true");
+ }
+ if (oldSerDeInfo == null || !oldSerDeInfo.equals(newSerDeInfo)) {
+ oldSd.setSerDeInfo(newSd.getSerDeInfo());
Review Comment:
can we reuse the variable from L5389?
Issue Time Tracking
-------------------
Worklog Id: (was: 792783)
Time Spent: 3h 10m (was: 3h)
> Deduplicate SerDe Info
> ----------------------
>
> Key: HIVE-25779
> URL: https://issues.apache.org/jira/browse/HIVE-25779
> Project: Hive
> Issue Type: New Feature
> Components: Standalone Metastore
> Reporter: Yu-Wen Lai
> Assignee: Yu-Wen Lai
> Priority: Major
> Labels: pull-request-available
> Time Spent: 3h 10m
> Remaining Estimate: 0h
>
> The proposal is that we can reuse serde info as how we reuse column
> descriptors. (HIVE-2246)
> Currently, we store the metadata for partitions as PARTITIONS (N partitions)
> -> SDS (N locations) -> SERDES (N entries). However, all the SERDES for the
> partitions in a table are the same if we don't explicitly specify it. That
> is, each storage descriptor has a associated and exclusive serde info, but
> the partitions' serde infos are mostly just the same as the table's. By
> reusing the serde info, we can save some database storage and enhance the
> query performance from HMS to the backend database.
> For backward compatibility, we also need to introduce a config for this
> feature because there will be issues if HMS old instance and HMS new instance
> with this feature are running together. With this feature, we will need to
> check if others reference the serdes before deleting it, but the old instance
> will just delete it.
> The other thing we need to take care of is custom serdes. If a partition's
> serde is modified, we need to create a new record in SERDES so that we don't
> interfere other partitions.
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