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Posted to issues@avro.apache.org by "ASF subversion and git services (Jira)" <ji...@apache.org> on 2023/02/09 13:03:00 UTC

[jira] [Commented] (AVRO-3531) GenericDatumReader in multithread lead to infinite loop cause misused of IdentityHashMap

    [ https://issues.apache.org/jira/browse/AVRO-3531?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17686457#comment-17686457 ] 

ASF subversion and git services commented on AVRO-3531:
-------------------------------------------------------

Commit 85113b882f894f35c8061f4b77cc5a4e19203604 in avro's branch refs/heads/avro-3631/fix-fixed-serialization from Martin Tzvetanov Grigorov
[ https://gitbox.apache.org/repos/asf?p=avro.git;h=85113b882 ]

AVRO-3531: Code formatting

Signed-off-by: Martin Tzvetanov Grigorov <mg...@apache.org>


> GenericDatumReader in multithread lead to infinite loop cause misused of IdentityHashMap
> ----------------------------------------------------------------------------------------
>
>                 Key: AVRO-3531
>                 URL: https://issues.apache.org/jira/browse/AVRO-3531
>             Project: Apache Avro
>          Issue Type: Bug
>          Components: java
>    Affects Versions: 1.11.0
>            Reporter: tansion
>            Assignee: Christophe Le Saec
>            Priority: Critical
>              Labels: pull-request-available
>             Fix For: 1.11.1
>
>          Time Spent: 2h
>  Remaining Estimate: 0h
>
> Hi, 
> I am working on a java project that uses Kafka with Avro serialization/deserialization in an messaging platform.
> In production enrionment, we meet a serious issue on the deserialization processs. The GenericDatumReader process some how get into a infinite loop status, and it is happened accationally.
> When the issue happens, The thread stack is like this:
>  
> {code:java}
> "DmqFixedRateConsumer-Thread-17" #453 daemon prio=5 os_prio=0 tid=0x00007f2ae1832800 nid=0xef49 runnable [0x00007f2a743fc000]
>    java.lang.Thread.State: RUNNABLE
>     at java.util.IdentityHashMap.get(IdentityHashMap.java:337)
>     at org.apache.avro.generic.GenericDatumReader.getStringClass(GenericDatumReader.java:503)
>     at org.apache.avro.generic.GenericDatumReader.readString(GenericDatumReader.java:454)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:191)
>     at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:160)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:187)
>     at org.apache.avro.reflect.ReflectDatumReader.readField(ReflectDatumReader.java:291)
>     at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:247)
>     at org.apache.avro.specific.SpecificDatumReader.readRecord(SpecificDatumReader.java:123)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:179)
>     at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:160)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:187)
>     at org.apache.avro.reflect.ReflectDatumReader.readField(ReflectDatumReader.java:291)
>     at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:247)
>     at org.apache.avro.specific.SpecificDatumReader.readRecord(SpecificDatumReader.java:123)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:179)
>     at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:160)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:187)
>     at org.apache.avro.reflect.ReflectDatumReader.readField(ReflectDatumReader.java:291)
>     at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:247)
>     at org.apache.avro.specific.SpecificDatumReader.readRecord(SpecificDatumReader.java:123)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:179)
>     at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:160)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:187)
>     at org.apache.avro.reflect.ReflectDatumReader.readField(ReflectDatumReader.java:291)
>     at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:247)
>     at org.apache.avro.specific.SpecificDatumReader.readRecord(SpecificDatumReader.java:123)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:179)
>     at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:160)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:187)
>     at org.apache.avro.reflect.ReflectDatumReader.readField(ReflectDatumReader.java:291)
>     at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:247)
>     at org.apache.avro.specific.SpecificDatumReader.readRecord(SpecificDatumReader.java:123)
>     at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:179)
>     at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:160)
>     at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:153)
>     at com.xxx.xxx.xxx.xxx.xxx.XXX.deserialize(XXX.java:252)
>     at com.xxx.xxx.xxx.xxx.xxx.ZZZ.deserialize(ZZZ.java:216)
>     at com.xxx.xxx.xxx.xxx.xxx.SSS.processMessage(SSS.java:152)
>     at com.xxx.xxx.xxx.xxx.xxx.SSS.loopProcess(SSS.java:127)
>     at com.xxx.xxx.xxx.xxx.xxx.SSS$$Lambda$172/367082698.run(Unknown Source)
>     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
>     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
>     at java.lang.Thread.run(Thread.java:748) {code}
> We create 30 threads, and all the threads are the same as above! They all get stuck in the IdentityHashMap.get() method.
>  
> Accroding to this mail [1.7.6 Slow Deserialization|https://www.mail-archive.com/user@avro.apache.org/msg02902.html], the Reader is thread-safe,  But actually, it seems not.
> Why?
> org.apache.avro.generic.GenericDatumReader#getStringClass
>  
> {code:java}
> /**
>  * Called to read strings. Subclasses may override to use a different string
>  * representation. By default, this calls {@link #readString(Object,Decoder)}.
>  */
> protected Object readString(Object old, Schema expected, Decoder in) throws IOException {
>   Class stringClass = getStringClass(expected);
>   if (stringClass == String.class) {
>     return in.readString();
>   }
>   if (stringClass == CharSequence.class) {
>     return readString(old, in);
>   }
>   return newInstanceFromString(stringClass, in.readString());
> }
> private Map<Schema, Class> stringClassCache = new IdentityHashMap<>();
> private Class getStringClass(Schema s) {
>   Class c = stringClassCache.get(s);
>   if (c == null) {
>     c = findStringClass(s);
>     stringClassCache.put(s, c);
>   }
>   return c;
> }
>  {code}
> The IdentityHashMap is not thread-safe, which is addressed by javadoc clearly! Like Hashmap infinite loop issue in multithread using, same issue happen to IdentityHashMap,too.
> My question is: Can the class GenericDatumReader fix this issue and act like  real thread-safe? Or we need to avoid use the single instance of GenericDatumReader in multithread?
> Thanks a lot,
>  Xtsong.
>  



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