Mithun Radhakrishnan created HIVE-17802:
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Summary: Remove unnecessary calls to FileSystem.setOwner() from
FileOutputCommitterContainer
Key: HIVE-17802
URL: https://issues.apache.org/jira/browse/HIVE-17802
Project: Hive
Issue Type: Bug
Components: HCatalog
Affects Versions: 2.2.0, 3.0.0
Reporter: Mithun Radhakrishnan
Assignee: Chris Drome
For large Pig/HCat queries that produce a large number of
partitions/directories/files, we have seen cases where the HDFS NameNode
groaned under the weight of {{FileSystem.setOwner()}} calls, originating from
the commit-step. This was the result of the following code in
FileOutputCommitterContainer:
{code:java}
private void applyGroupAndPerms(FileSystem fs, Path dir, FsPermission
permission,
List<AclEntry> acls, String group, boolean recursive)
throws IOException {
...
if (recursive) {
for (FileStatus fileStatus : fs.listStatus(dir)) {
if (fileStatus.isDir()) {
applyGroupAndPerms(fs, fileStatus.getPath(), permission, acls, group,
true);
} else {
fs.setPermission(fileStatus.getPath(), permission);
chown(fs, fileStatus.getPath(), group);
}
}
}
}
private void chown(FileSystem fs, Path file, String group) throws IOException
{
try {
fs.setOwner(file, null, group);
} catch (AccessControlException ignore) {
// Some users have wrong table group, ignore it.
LOG.warn("Failed to change group of partition directories/files: " +
file, ignore);
}
}
{code}
One call per file/directory is far too many. We have a patch that reduces the
namenode pressure.
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