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https://issues.apache.org/jira/browse/HIVE-24397?focusedWorklogId=518760&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-518760
]
ASF GitHub Bot logged work on HIVE-24397:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 02/Dec/20 04:18
Start Date: 02/Dec/20 04:18
Worklog Time Spent: 10m
Work Description: nrg4878 commented on a change in pull request #1681:
URL: https://github.com/apache/hive/pull/1681#discussion_r533886236
##########
File path:
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java
##########
@@ -1855,43 +1869,89 @@ private MTable getMTable(String catName, String db,
String table) {
for (String t : tbl_names) {
lowered_tbl_names.add(normalizeIdentifier(t));
}
+
query = pm.newQuery(MTable.class);
query.setFilter("database.name == db && database.catalogName == cat &&
tbl_names.contains(tableName)");
query.declareParameters("java.lang.String db, java.lang.String cat,
java.util.Collection tbl_names");
- Collection mtables = (Collection) query.execute(db, catName,
lowered_tbl_names);
- if (mtables == null || mtables.isEmpty()) {
- // Need to differentiate between an unmatched pattern and a
non-existent database
- dbExistsQuery = pm.newQuery(MDatabase.class, "name == db &&
catalogName == cat");
- dbExistsQuery.declareParameters("java.lang.String db, java.lang.String
cat");
- dbExistsQuery.setUnique(true);
- dbExistsQuery.setResult("name");
- String dbNameIfExists = (String) dbExistsQuery.execute(db, catName);
- if (org.apache.commons.lang3.StringUtils.isEmpty(dbNameIfExists)) {
- throw new UnknownDBException("Could not find database " +
- DatabaseName.getQualified(catName, db));
+
+ List<String> projectionFields = null;
+
+ // If a projection specification has been set, validate it and translate
it to JDO columns.
+ if (projectionSpec != null) {
+ //Validate the projection fields for multi-valued fields.
+ projectionFields =
TableFields.getMFieldNames(projectionSpec.getFieldList());
+ }
+
+ // If the JDO translation resulted in valid JDO columns names, use it to
create a projection for the JDO query.
+ if (projectionFields != null) {
+ // fetch partially filled tables using result clause
+ query.setResult(Joiner.on(',').join(projectionFields));
+ }
+
+ if (projectionFields == null) {
+ mtables = (List<MTable>) query.execute(db, catName, lowered_tbl_names);
+ } else {
+ if (projectionFields.size() > 1) {
+ // Execute the query to fetch the partial results.
+ List<Object[]> results = (List<Object[]>) query.execute(db, catName,
lowered_tbl_names);
+ // Declare the tables array to return the list of tables
+ mtables = new ArrayList<>(results.size());
+ // Iterate through each row of the result and create the MTable
object.
+ for (Object[] row : results) {
+ MTable mtable = new MTable();
+ int i = 0;
+ for (Object val : row) {
+ MetaStoreServerUtils.setNestedProperty(mtable,
projectionFields.get(i), val, true);
+ i++;
+ }
+ mtables.add(mtable);
+ }
+ } else if (projectionFields.size() == 1) {
+ // Execute the query to fetch the partial results.
+ List<Object> results = (List<Object>) query.execute(db, catName,
lowered_tbl_names);
+ // Iterate through each row of the result and create the MTable
object.
+ mtables = new ArrayList<>(results.size());
+ for (Object row : results) {
+ MTable mtable = new MTable();
+ MetaStoreServerUtils.setNestedProperty(mtable,
projectionFields.get(0), row, true);
+ mtables.add(mtable);
+ }
}
+ }
+
+ if (mtables == null || mtables.isEmpty()) {
+ verifyDBExists(catName, db);
Review comment:
feels like we should just call getDatabaseInternal() and remove this
refactored code verifyDBExists() code altogether. verifyDBExists() only fetches
a single column (dbName) in a resultset of 1 row if the DB exists where as
getDatabaseInternal() fetches few additional columns in a resultset of 1 row. I
dont think it would be a huge performance degradation but the code will be bit
cleaner. What do you think?
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Issue Time Tracking
-------------------
Worklog Id: (was: 518760)
Time Spent: 1h 20m (was: 1h 10m)
> Add the projection specification to the table request object and add
> placeholders in ObjectStore.java
> -----------------------------------------------------------------------------------------------------
>
> Key: HIVE-24397
> URL: https://issues.apache.org/jira/browse/HIVE-24397
> Project: Hive
> Issue Type: Sub-task
> Components: Hive
> Reporter: Narayanan Venkateswaran
> Assignee: Narayanan Venkateswaran
> Priority: Minor
> Labels: pull-request-available
> Time Spent: 1h 20m
> Remaining Estimate: 0h
>
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