Anthony Hsu created HIVE-13132:
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Summary: Hive should lazily load and cache metastore (permanent)
functions
Key: HIVE-13132
URL: https://issues.apache.org/jira/browse/HIVE-13132
Project: Hive
Issue Type: Improvement
Affects Versions: 0.13.1
Reporter: Anthony Hsu
Assignee: Anthony Hsu
In Hive 0.13.1, we have noticed that as the number of databases increases, the
start-up time of the Hive interactive shell increases. This is because during
start-up, all databases are iterated over to fetch the permanent functions to
display in the {{SHOW FUNCTIONS}} output.
{noformat:title=FunctionRegistry.java}
private static Set<String> getFunctionNames(boolean searchMetastore) {
Set<String> functionNames = mFunctions.keySet();
if (searchMetastore) {
functionNames = new HashSet<String>(functionNames);
try {
Hive db = getHive();
List<String> dbNames = db.getAllDatabases();
for (String dbName : dbNames) {
List<String> funcNames = db.getFunctions(dbName, "*");
for (String funcName : funcNames) {
functionNames.add(FunctionUtils.qualifyFunctionName(funcName,
dbName));
}
}
} catch (Exception e) {
LOG.error(e);
// Continue on, we can still return the functions we've gotten to this
point.
}
}
return functionNames;
}
{noformat}
Instead of eagerly loading all metastore functions, we should only load them
the first time {{SHOW FUNCTIONS}} is invoked. We should also cache the results.
Note that this issue may have been fixed by HIVE-2573, though I haven't
verified this.
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