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https://issues.apache.org/jira/browse/HIVE-25779?focusedWorklogId=789381&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-789381
]
ASF GitHub Bot logged work on HIVE-25779:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 11/Jul/22 07:11
Start Date: 11/Jul/22 07:11
Worklog Time Spent: 10m
Work Description: dengzhhu653 commented on code in PR #3221:
URL: https://github.com/apache/hive/pull/3221#discussion_r917607723
##########
standalone-metastore/metastore-server/src/test/java/org/apache/hadoop/hive/metastore/TestObjectStore.java:
##########
@@ -1483,6 +1483,135 @@ public void testListPackage() throws Exception {
Assert.assertEquals(1, result.size());
}
+ @Test
+ public void testSerDeCreatedOnDemand() throws Exception {
+ // Enable USE_TABLE_SERDES
+ final boolean origUseTableSerDes = MetastoreConf.getBoolVar(conf,
ConfVars.USE_TABLE_SERDES);
+ if (!origUseTableSerDes) {
+ MetastoreConf.setBoolVar(conf, ConfVars.USE_TABLE_SERDES, true);
+ objectStore.setConf(conf);
+ }
+
+ createPartitionedTable(true, true);
+ // Partitions should reuse table's serde info
+ checkBackendTableSize("PARTITIONS", 3);
+ checkBackendTableSize("SERDES", 1);
+ checkBackendTableSize("SERDE_PARAMS", 1);
+ Table tbl;
+ Partition newPart;
+ // Alters table's serde info
+ try (AutoCloseable c = deadline()) {
+ tbl = objectStore.getTable(DEFAULT_CATALOG_NAME, DB1, TABLE1);
+ Table newTbl = tbl.deepCopy();
+ newTbl.getSd().getSerdeInfo().setDescription("To test SerDe is created
on demand");
+ objectStore.alterTable(DEFAULT_CATALOG_NAME, DB1, TABLE1, newTbl, null);
+ }
+ // A new SERDE should be created
+ checkBackendTableSize("SERDES", 2);
+ checkBackendTableSize("SERDE_PARAMS", 2);
+ // Alter a partition's serde info
+ List<String> partVals = Collections.singletonList("a0");
+ try (AutoCloseable c = deadline()) {
+ Partition part = objectStore.getPartition(DEFAULT_CATALOG_NAME, DB1,
TABLE1, partVals);
+ newPart = part.deepCopy();
+ newPart.getSd().getSerdeInfo().setDescription("To test SerDe is created
on demand");
+ objectStore.alterPartition(DEFAULT_CATALOG_NAME, DB1, TABLE1, partVals,
newPart, null);
+ }
+ // A new SERDE should be created
+ checkBackendTableSize("SERDES", 3);
+ checkBackendTableSize("SERDE_PARAMS", 3);
+ // Adds a partition with different serde
+ newPart.setValues(Collections.singletonList("a3"));
+ newPart.getSd().getSerdeInfo().setDescription("To test adding a partition
with different SerDe");
+ objectStore.addPartition(newPart);
+ // A new SERDE should be created
+ checkBackendTableSize("SERDES", 4);
+ checkBackendTableSize("SERDE_PARAMS", 4);
+
+ // Restore conf
+ if (!origUseTableSerDes) {
+ MetastoreConf.setBoolVar(conf, ConfVars.USE_TABLE_SERDES, false);
+ objectStore.setConf(conf);
+ }
+ }
+
+ @Test
+ public void testSerDesCleanup() throws Exception {
+ // Enable USE_TABLE_SERDES
+ final boolean origUseTableSerDes = MetastoreConf.getBoolVar(conf,
ConfVars.USE_TABLE_SERDES);
+ if (!origUseTableSerDes) {
+ MetastoreConf.setBoolVar(conf, ConfVars.USE_TABLE_SERDES, true);
+ objectStore.setConf(conf);
+ }
+
+ createPartitionedTable(true, true);
+ // Partitions should reuse table's serde info
+ checkBackendTableSize("PARTITIONS", 3);
+ checkBackendTableSize("SERDES", 1);
+ checkBackendTableSize("SERDE_PARAMS", 1);
+ // Alters a partition's serde info
+ List<String> partVals = Collections.singletonList("a0");
+ Partition newPart;
+ try (AutoCloseable c = deadline()) {
+ Partition part = objectStore.getPartition(DEFAULT_CATALOG_NAME, DB1,
TABLE1, partVals);
+ newPart = part.deepCopy();
Review Comment:
yeah, that it.
Issue Time Tracking
-------------------
Worklog Id: (was: 789381)
Time Spent: 2.5h (was: 2h 20m)
> 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: 2.5h
> 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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