Zheng Shao created SPARK-47959: ---------------------------------- Summary: Improve GET_JSON_OBJECT performance on executors running multiple tasks Key: SPARK-47959 URL: https://issues.apache.org/jira/browse/SPARK-47959 Project: Spark Issue Type: Improvement Components: Spark Core Affects Versions: 3.5.1 Reporter: Zheng Shao
We have a Spark executor that is running 32 workers in parallel. The query is a simple SELECT with several `GET_JSON_OBJECT` UDF calls. We noticed that 80+% of the stacktrace of the worker threads are blocked on the following stacktrace: ``` com.fasterxml.jackson.core.util.InternCache.intern(InternCache.java:50) - blocked on java.lang.Object@7529fde1 com.fasterxml.jackson.core.sym.ByteQuadsCanonicalizer.addName(ByteQuadsCanonicalizer.java:947) com.fasterxml.jackson.core.json.UTF8StreamJsonParser.addName(UTF8StreamJsonParser.java:2482) com.fasterxml.jackson.core.json.UTF8StreamJsonParser.findName(UTF8StreamJsonParser.java:2339) com.fasterxml.jackson.core.json.UTF8StreamJsonParser.parseMediumName(UTF8StreamJsonParser.java:1870) com.fasterxml.jackson.core.json.UTF8StreamJsonParser._parseName(UTF8StreamJsonParser.java:1825) com.fasterxml.jackson.core.json.UTF8StreamJsonParser.nextToken(UTF8StreamJsonParser.java:798) com.fasterxml.jackson.core.base.ParserMinimalBase.skipChildren(ParserMinimalBase.java:240) org.apache.spark.sql.catalyst.expressions.GetJsonObjectBase.evaluatePath(jsonExpressions.scala:383) org.apache.spark.sql.catalyst.expressions.GetJsonObjectBase.evaluatePath(jsonExpressions.scala:287) org.apache.spark.sql.catalyst.expressions.GetJsonObjectBase.$anonfun$eval$4(jsonExpressions.scala:198) org.apache.spark.sql.catalyst.expressions.GetJsonObjectBase.$anonfun$eval$4$adapted(jsonExpressions.scala:196) org.apache.spark.sql.catalyst.expressions.GetJsonObjectBase$$Lambda$8585/1316745697.apply(Unknown Source) ... ``` Apparently jackson-core has such a performance bug from version 2.3 - 2.15, and not fixed until version 2.18 (unreleased): [https://github.com/FasterXML/jackson-core/blob/fc51d1e13f4ba62a25a739f26be9e05aaad[…]/src/main/java/com/fasterxml/jackson/core/util/InternCache.java|https://github.com/FasterXML/jackson-core/blob/fc51d1e13f4ba62a25a739f26be9e05aaad88c3e/src/main/java/com/fasterxml/jackson/core/util/InternCache.java#L50] synchronized (lock) { if (size() >= MAX_ENTRIES) { clear(); } } instead of [https://github.com/FasterXML/jackson-core/blob/8b87cc1a96f649a7e7872c5baa8cf97909c[…]/src/main/java/com/fasterxml/jackson/core/util/InternCache.java|https://github.com/FasterXML/jackson-core/blob/8b87cc1a96f649a7e7872c5baa8cf97909cabf6b/src/main/java/com/fasterxml/jackson/core/util/InternCache.java#L59] /* As of 2.18, the limit is not strictly enforced, but we do try to * clear entries if we have reached the limit. We do not expect to * go too much over the limit, and if we do, it's not a huge problem. * If some other thread has the lock, we will not clear but the lock should * not be held for long, so another thread should be able to clear in the near future. */ if (lock.tryLock()) { try { if (size() >= DEFAULT_MAX_ENTRIES) { clear(); } } finally { lock.unlock(); } } -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org