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https://issues.apache.org/jira/browse/HIVE-25779?focusedWorklogId=787486&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-787486
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ASF GitHub Bot logged work on HIVE-25779:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 04/Jul/22 04:56
Start Date: 04/Jul/22 04:56
Worklog Time Spent: 10m
Work Description: dengzhhu653 commented on code in PR #3221:
URL: https://github.com/apache/hive/pull/3221#discussion_r912625962
##########
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java:
##########
@@ -5112,6 +5153,12 @@ private Partition alterPartitionNoTxn(String catName,
String dbname,
oldp.setParameters(newPart.getParameters());
if (!TableType.VIRTUAL_VIEW.name().equals(oldp.getTable().getTableType()))
{
copyMSD(newp.getSd(), oldp.getSd());
+ if (oldSD != null && oldSD.getCD() != oldCD) {
+ oldCdRef.t = oldCD;
+ }
+ if (oldSD != null && oldSD.getSerDeInfo() != oldSerDeInfo) {
Review Comment:
it seems that oldSD.getSerDeInfo() always be oldSerDeInfo
Issue Time Tracking
-------------------
Worklog Id: (was: 787486)
Time Spent: 1h 20m (was: 1h 10m)
> 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: 1h 20m
> 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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