Gopal V created HIVE-11472:
------------------------------
Summary: ORC StringDirectTreeReader is thrashing the GC due to
byte[] allocation per row
Key: HIVE-11472
URL: https://issues.apache.org/jira/browse/HIVE-11472
Project: Hive
Issue Type: Bug
Affects Versions: 1.3.0, 2.0.0
Reporter: Gopal V
Fix For: 1.3.0, 2.0.0
For every row x column
{code}
int len = (int) lengths.next();
int offset = 0;
byte[] bytes = new byte[len];
while (len > 0) {
int written = stream.read(bytes, offset, len);
if (written < 0) {
throw new EOFException("Can't finish byte read from " + stream);
}
{code}
https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/io/orc/TreeReaderFactory.java#L1552
This is not a big issue until it misses the GC TLAB.
>From hadoop-2.6.x (HADOOP-10855) you can read into a Text directly.
Possibly can create a different TreeReader from the factory for 2.6.x & use a
DataInputStream per stream and prevent an allocation in the inner loop.
{code}
int len = (int) lengths.next();
result.readWithKnownLength(datastream, len);
{code}
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