![Nov 23, 2021 · java.lang.OutOfMemoryError: GC overhead limit exceeded. [ solved ] Go to solution. sarvesh. Contributor III. Options. 11-22-2021 09:51 PM. solution :-. i don't need to add any executor or driver memory all i had to do in my case was add this : - option ("maxRowsInMemory", 1000). Before i could n't even read a 9mb file now i just read a 50mb ... . All inclusive vacations](/img/512x512/490298198529.webp)
7. I am getting a java.lang.OutOfMemoryError: GC overhead limit exceeded exception when I try to run the program below. This program's main method access' a specified directory and iterates over all the files that contain .xlsx. This works fine as I tested it before any of the other logic.I've set the overhead memory needed for spark_apply using spark.yarn.executor.memoryOverhead. I've found that using the by= argument of sfd_repartition is useful and using the group_by= in spark_apply also helps.For debugging run through the Spark shell, Zeppelin adds over head and takes a decent amount of YARN resources and RAM. Run on Spark 1.6 / HDP 2.4.2 if you can. Allocate as much memory as possible.Nov 23, 2021 · java.lang.OutOfMemoryError: GC overhead limit exceeded. [ solved ] Go to solution. sarvesh. Contributor III. Options. 11-22-2021 09:51 PM. solution :-. i don't need to add any executor or driver memory all i had to do in my case was add this : - option ("maxRowsInMemory", 1000). Before i could n't even read a 9mb file now i just read a 50mb ... Excessive GC Time and OutOfMemoryError. The parallel collector will throw an OutOfMemoryError if too much time is being spent in garbage collection: if more than 98% of the total time is spent in garbage collection and less than 2% of the heap is recovered, an OutOfMemoryError will be thrown. This feature is designed to prevent applications ...1. I had this problem several times, sometimes randomly. What helped me so far was using the following command at the beginning of the script before loading any other package! options (java.parameters = c ("-XX:+UseConcMarkSweepGC", "-Xmx8192m")) The -XX:+UseConcMarkSweepGC loads an alternative garbage collector which seemed to make less ...Oct 24, 2017 · I'm running a Spark application (Spark 1.6.3 cluster), which does some calculations on 2 small data sets, and writes the result into an S3 Parquet file. Here is my code: public void doWork( Spark seems to keep all in memory until it explodes with a java.lang.OutOfMemoryError: GC overhead limit exceeded. I am probably doing something really basic wrong but I couldn't find any pointers on how to come forward from this, I would like to know how I can avoid this.The GC Overhead Limit Exceeded error is one from the java.lang.OutOfMemoryError family, and it’s an indication of a resource (memory) exhaustion. In this quick tutorial, we’ll look at what causes the java.lang.OutOfMemoryError: GC Overhead Limit Exceeded error and how it can be solved.Since you are running Spark in local mode, setting spark.executor.memory won't have any effect, as you have noticed. The reason for this is that the Worker "lives" within the driver JVM process that you start when you start spark-shell and the default memory used for that is 512M.and, when i run this script on spark-shell i got following error, after running line of code simsPerfect_entries.count(): java.lang.OutOfMemoryError: GC overhead limit exceeded Updated: I tried many solutions already given by others ,but i got no success. 1 By increasing amount of memory to use per executor process spark.executor.memory=1gCause: The detail message "GC overhead limit exceeded" indicates that the garbage collector is running all the time and Java program is making very slow progress. After a garbage collection, if the Java process is spending more than approximately 98% of its time doing garbage collection and if it is recovering less than 2% of the heap and has been doing so far the last 5 (compile time constant ...The default behavior for Apache Hive joins is to load the entire contents of a table into memory so that a join can be performed without having to perform a Map/Reduce step. If the Hive table is too large to fit into memory, the query can fail.May 16, 2022 · In this article, we examined the java.lang.OutOfMemoryError: GC Overhead Limit Exceeded and the reasons behind it. As always, the source code related to this article can be found over on GitHub . Course – LS (cat=Java) Aug 18, 2015 · GC overhead limit exceeded is thrown when the cpu spends more than 98% for garbage collection tasks. It happens in Scala when using immutable data structures since that for each transformation the JVM will have to re-create a lot of new objects and remove the previous ones from the heap. ./bin/spark-submit ~/mysql2parquet.py --conf "spark.executor.memory=29g" --conf "spark.storage.memoryFraction=0.9" --conf "spark.executor.extraJavaOptions=-XX:-UseGCOverheadLimit" --driver-memory 29G --executor-memory 29G When I run this script on a EC2 instance with 30 GB, it fails with java.lang.OutOfMemoryError: GC overhead limit exceeded4) If the new generation size is explicitly defined with JVM options (e.g. -XX:NewSize, -XX:MaxNewSize), decrease the size or remove the relevant JVM options entirely to unconstrain the JVM and provide more space in the old generation for long lived objects.In this article, we examined the java.lang.OutOfMemoryError: GC Overhead Limit Exceeded and the reasons behind it. As always, the source code related to this article can be found over on GitHub . Course – LS (cat=Java)Feb 5, 2019 · Sorted by: 1. The difference was in available memory for driver. I found out it by zeppelin-interpreter-spark.log: memorystore started with capacity .... When I used bult-in spark it was 2004.6 MB for external spark it was 366.3 MB. So, I increased available memory for driver by setting spark.driver.memory in zeppelin gui. It solved the problem. Why does Spark fail with java.lang.OutOfMemoryError: GC overhead limit exceeded? Related questions. 11 ... Spark memory limit exceeded issue. 2Sep 26, 2019 · 4) If the new generation size is explicitly defined with JVM options (e.g. -XX:NewSize, -XX:MaxNewSize), decrease the size or remove the relevant JVM options entirely to unconstrain the JVM and provide more space in the old generation for long lived objects. I've narrowed down the problem to only 1 of 8 excel files. I can consistently reproduce it on that particular excel file. It opens up just fine using microsoft excel, so I'm puzzled why only 1 particular excel file gives me an issue.3. When JVM/Dalvik spends more than 98% doing GC and only 2% or less of the heap size is recovered the “ java.lang.OutOfMemoryError: GC overhead limit exceeded ” is thrown. The solution is to extend heap space or use profiling tools/memory dump analyzers and try to find the cause of the problem. Share.Created on 08-04-2014 10:38 AM - edited 09-16-2022 02:04 AM. I got a 40 node cdh 5.1 cluster and attempting to run a simple spark app that processes about 10-15GB raw data but I keep running into this error: java.lang.OutOfMemoryError: GC overhead limit exceeded. Each node has 8 cores and 2GB memory. I notice the heap size on the ...I'm running a Spark application (Spark 1.6.3 cluster), which does some calculations on 2 small data sets, and writes the result into an S3 Parquet file. Here is my code: public void doWork(So, the key is to " Prepend that environment variable " (1st time seen this linux command syntax :) ) HADOOP_CLIENT_OPTS="-Xmx10g" hadoop jar "your.jar" "source.dir" "target.dir". GC overhead limit indicates that your (tiny) heap is full. This is what often happens in MapReduce operations when u process a lot of data.Hi, everybody! I have a hadoop cluster on yarn. There are about Memory Total: 8.98 TB VCores Total: 1216 my app has followinng config (python api): spark = ( pyspark.sql.SparkSession .builder .mast...Sep 26, 2019 · The same application code will not trigger the OutOfMemoryError: GC overhead limit exceeded when upgrading to JDK 1.8 and using the G1GC algorithm. 4) If the new generation size is explicitly defined with JVM options (e.g. -XX:NewSize, -XX:MaxNewSize), decrease the size or remove the relevant JVM options entirely to unconstrain the JVM and ... 1 Answer. You are exceeding driver capacity (6GB) when calling collectToPython. This makes sense as your executor has much larger memory limit than the driver (12Gb). The problem I see in your case is that increasing driver memory may not be a good solution as you are already near the virtual machine limits (16GB).scala.MatchError: java.lang.OutOfMemoryError: Java heap space (of class java.lang.OutOfMemoryError) Cause. This issue is often caused by a lack of resources when opening large spark-event files. The Spark heap size is set to 1 GB by default, but large Spark event files may require more than this.Nov 13, 2018 · I have some data on postgres and trying to read that data on spark dataframe but i get error java.lang.OutOfMemoryError: GC overhead limit exceeded. I am using ... Dropping event SparkListenerJobEnd(0,1499762732342,JobFailed(org.apache.spark.SparkException: Job 0 cancelled because SparkContext was shut down)) 17/07/11 14:15:32 ERROR SparkUncaughtExceptionHandler: [Container in shutdown] Uncaught exception in thread Thread[Executor task launch worker-1,5,main] java.lang.OutOfMemoryError: GC overhead limit ...Aug 4, 2014 · I got a 40 node cdh 5.1 cluster and attempting to run a simple spark app that processes about 10-15GB raw data but I keep running into this error: java.lang.OutOfMemoryError: GC overhead limit exceeded. Each node has 8 cores and 2GB memory. I notice the heap size on the executors is set to 512MB with total set to 2GB. java.lang.OutOfMemoryError: GC overhead limit exceeded. ... java.lang.OutOfMemoryError: GC overhead limit exceeded? ... Spark executor lost because of GC overhead ...In this article, we examined the java.lang.OutOfMemoryError: GC Overhead Limit Exceeded and the reasons behind it. As always, the source code related to this article can be found over on GitHub . Course – LS (cat=Java)Jan 18, 2022 · Closed. 3 tasks. ulysses-you added a commit that referenced this issue on Jan 19, 2022. [KYUUBI #1800 ] [1.4] Remove oom hook. 952efb5. ulysses-you mentioned this issue on Feb 17, 2022. [Bug] SparkContext stopped abnormally, but the KyuubiEngine did not stop. #1924. Closed. It's always better to deploy each web application into their own tomcat instance, because it not only reduce memory overhead but also prevent other application from crashing due to one application hit by large requests. To avoid "java.lang.OutOfMemoryError: GC overhead limit exceeded" in Eclipse, close open process, unused files etc.7. I am getting a java.lang.OutOfMemoryError: GC overhead limit exceeded exception when I try to run the program below. This program's main method access' a specified directory and iterates over all the files that contain .xlsx. This works fine as I tested it before any of the other logic.Dec 16, 2020 · java.lang.OutOfMemoryError: GC Overhead limit exceeded; java.lang.OutOfMemoryError: Java heap space. Note: JavaHeapSpace OOM can occur if the system doesn’t have enough memory for the data it needs to process. In some cases, choosing a bigger instance like i3.4x large(16 vCPU, 122Gib ) can solve the problem. 1. I had this problem several times, sometimes randomly. What helped me so far was using the following command at the beginning of the script before loading any other package! options (java.parameters = c ("-XX:+UseConcMarkSweepGC", "-Xmx8192m")) The -XX:+UseConcMarkSweepGC loads an alternative garbage collector which seemed to make less ...Just before this exception worker was repeatedly launching an executor as executor was exiting :-. EXITING with Code 1 and exitStatus 1. Configs:-. -Xmx for worker process = 1GB. Total RAM on worker node = 100GB. Java 8. Spark 2.2.1. When this exception occurred , 90% of system memory was free. After this expection the process is still up but ...The default behavior for Apache Hive joins is to load the entire contents of a table into memory so that a join can be performed without having to perform a Map/Reduce step. If the Hive table is too large to fit into memory, the query can fail.Exception in thread "Thread-11" java.lang.OutOfMemoryError: GC overhead limit exceeded How to fix this problem ? i have change become java -Xmx2G -jar [file].jarSep 8, 2009 · Excessive GC Time and OutOfMemoryError. The parallel collector will throw an OutOfMemoryError if too much time is being spent in garbage collection: if more than 98% of the total time is spent in garbage collection and less than 2% of the heap is recovered, an OutOfMemoryError will be thrown. This feature is designed to prevent applications ... 4) If the new generation size is explicitly defined with JVM options (e.g. -XX:NewSize, -XX:MaxNewSize), decrease the size or remove the relevant JVM options entirely to unconstrain the JVM and provide more space in the old generation for long lived objects.Apr 14, 2020 · When calling on the read operation, spark first does a step where it lists all underlying files in S3, which is executed successfully. After this it does an initial load of all the data to construct a composite json schema for all files. Why does Spark fail with java.lang.OutOfMemoryError: GC overhead limit exceeded? Related questions. 11 ... Spark memory limit exceeded issue. 2We have a spark SQL query that returns over 5 million rows. Collecting them all for processing results in java.lang.OutOfMemoryError: GC overhead limit exceeded (eventually).For debugging run through the Spark shell, Zeppelin adds over head and takes a decent amount of YARN resources and RAM. Run on Spark 1.6 / HDP 2.4.2 if you can. Allocate as much memory as possible.Sorted by: 2. From the logs it looks like the driver is running out of memory. For certain actions like collect, rdd data from all workers is transferred to the driver JVM. Check your driver JVM settings. Avoid collecting so much data onto driver JVM. Share. Improve this answer. Follow.When I train the spark-nlp CRF model, emerged java.lang.OutOfMemoryError: GC overhead limit exceeded error Description I found the training process only run on driver ...Here a fragment that I used first with Spark-Shell (sshell on my terminal), Add memory by most popular directives, sshell --driver-memory 12G --executor-memory 24G Remove the most internal (and problematic) loop, reducing int to parts = fs.listStatus( new Path(t) ).length and enclosing it into a try directive.Hi, everybody! I have a hadoop cluster on yarn. There are about Memory Total: 8.98 TB VCores Total: 1216 my app has followinng config (python api): spark = ( pyspark.sql.SparkSession .builder .mast...But if your application genuinely needs more memory may be because of increased cache size or the introduction of new caches then you can do the following things to fix java.lang.OutOfMemoryError: GC overhead limit exceeded in Java: 1) Increase the maximum heap size to a number that is suitable for your application e.g. -Xmx=4G.Sorted by: 2. From the logs it looks like the driver is running out of memory. For certain actions like collect, rdd data from all workers is transferred to the driver JVM. Check your driver JVM settings. Avoid collecting so much data onto driver JVM. Share. Improve this answer. Follow.For debugging run through the Spark shell, Zeppelin adds over head and takes a decent amount of YARN resources and RAM. Run on Spark 1.6 / HDP 2.4.2 if you can. Allocate as much memory as possible.The default behavior for Apache Hive joins is to load the entire contents of a table into memory so that a join can be performed without having to perform a Map/Reduce step. If the Hive table is too large to fit into memory, the query can fail.GC Overhead limit exceeded. — Increase executor memory. At times we also need to check if the value for spark.storage.memoryFraction has not been set to a higher value (>0.6).Just before this exception worker was repeatedly launching an executor as executor was exiting :-. EXITING with Code 1 and exitStatus 1. Configs:-. -Xmx for worker process = 1GB. Total RAM on worker node = 100GB. Java 8. Spark 2.2.1. When this exception occurred , 90% of system memory was free. After this expection the process is still up but ...java.lang.OutOfMemoryError: GC overhead limit exceeded. [ solved ] Go to solution. sarvesh. Contributor III. Options. 11-22-2021 09:51 PM. solution :-. i don't need to add any executor or driver memory all i had to do in my case was add this : - option ("maxRowsInMemory", 1000). Before i could n't even read a 9mb file now i just read a 50mb ...Spark DataFrame java.lang.OutOfMemoryError: GC overhead limit exceeded on long loop run 6 Pyspark: java.lang.OutOfMemoryError: GC overhead limit exceededSpark seems to keep all in memory until it explodes with a java.lang.OutOfMemoryError: GC overhead limit exceeded. I am probably doing something really basic wrong but I couldn't find any pointers on how to come forward from this, I would like to know how I can avoid this.Create a temporary dataframe by limiting number of rows after you read the json and create table view on this smaller dataframe. E.g. if you want to read only 1000 rows, do something like this: small_df = entire_df.limit (1000) and then create view on top of small_df. You can increase the cluster resources. I've never used Databricks runtime ...Nov 13, 2018 · I have some data on postgres and trying to read that data on spark dataframe but i get error java.lang.OutOfMemoryError: GC overhead limit exceeded. I am using ... Sorted by: 2. From the logs it looks like the driver is running out of memory. For certain actions like collect, rdd data from all workers is transferred to the driver JVM. Check your driver JVM settings. Avoid collecting so much data onto driver JVM. Share. Improve this answer. Follow.Sep 26, 2019 · The same application code will not trigger the OutOfMemoryError: GC overhead limit exceeded when upgrading to JDK 1.8 and using the G1GC algorithm. 4) If the new generation size is explicitly defined with JVM options (e.g. -XX:NewSize, -XX:MaxNewSize), decrease the size or remove the relevant JVM options entirely to unconstrain the JVM and ... 7. I am getting a java.lang.OutOfMemoryError: GC overhead limit exceeded exception when I try to run the program below. This program's main method access' a specified directory and iterates over all the files that contain .xlsx. This works fine as I tested it before any of the other logic.The detail message "GC overhead limit exceeded" indicates that the garbage collector is running all the time and Java program is making very slow progress. Can be fixed in 2 ways 1) By Suppressing GC Overhead limit warning in JVM parameter Ex- -Xms1024M -Xmx2048M -XX:+UseConcMarkSweepGC -XX:-UseGCOverheadLimit. Sep 8, 2009 · Excessive GC Time and OutOfMemoryError. The parallel collector will throw an OutOfMemoryError if too much time is being spent in garbage collection: if more than 98% of the total time is spent in garbage collection and less than 2% of the heap is recovered, an OutOfMemoryError will be thrown. This feature is designed to prevent applications ... Spark DataFrame java.lang.OutOfMemoryError: GC overhead limit exceeded on long loop run 0 Java Spark - java.lang.OutOfMemoryError: GC overhead limit exceeded - Large DatasetI have some data on postgres and trying to read that data on spark dataframe but i get error java.lang.OutOfMemoryError: GC overhead limit exceeded. I am using ...Getting OutofMemoryError- GC overhead limit exceed in pyspark. 34,090. The simplest thing to try would be increasing spark executor memory: spark.executor.memory=6g. Make sure you're using all the available memory. You can check that in UI. UPDATE 1. --conf spark.executor.extrajavaoptions="Option" you can pass -Xmx1024m as an option.POI is notoriously memory-hungry, so running out of memory is not uncommon when handling large Excel-files. When you are able to load all original files and only get trouble writing the merged file you could try using an SXSSFWorkbook instead of an XSSFWorkbook and do regular flushes after adding a certain amount of content (see poi-documentation of the org.apache.poi.xssf.streaming-package).Spark DataFrame java.lang.OutOfMemoryError: GC overhead limit exceeded on long loop run 0 Java Spark - java.lang.OutOfMemoryError: GC overhead limit exceeded - Large DatasetSep 23, 2018 · Spark: java.lang.OutOfMemoryError: GC overhead limit exceeded Hot Network Questions AI tricks space pirates into attacking its ship; kills all but one as part of effort to "civilize" space Jan 18, 2022 · Closed. 3 tasks. ulysses-you added a commit that referenced this issue on Jan 19, 2022. [KYUUBI #1800 ] [1.4] Remove oom hook. 952efb5. ulysses-you mentioned this issue on Feb 17, 2022. [Bug] SparkContext stopped abnormally, but the KyuubiEngine did not stop. #1924. Closed. How do I resolve "OutOfMemoryError" Hive Java heap space exceptions on Amazon EMR that occur when Hive outputs the query results?@Sandeep Nemuri. I have resolved this issue with increasing spark_daemon_memory in spark configuration . Advanced spark2-env.Apr 18, 2020 · Hive's OrcInputFormat has three (basically two) strategies for split calculation: BI — it is set for small fast queries where you don't want to spend very much time in split calculations and it just reads the blocks and splits blindly based on HDFS blocks and it deals with it after that. ETL — is for large queries that one it actually reads ... Nov 13, 2018 · I have some data on postgres and trying to read that data on spark dataframe but i get error java.lang.OutOfMemoryError: GC overhead limit exceeded. I am using ... Pyspark: java.lang.OutOfMemoryError: GC overhead limit exceeded Hot Network Questions Usage of the word "deployment" in a software development context For Windows, I solved the GC overhead limit exceeded issue, by modifying the environment MAVEN_OPTS variable value with: -Xmx1024M -Xss128M -XX:MetaspaceSize=512M -XX:MaxMetaspaceSize=1024M -XX:+CMSClassUnloadingEnabled. Share. Improve this answer. Follow.Since you are running Spark in local mode, setting spark.executor.memory won't have any effect, as you have noticed. The reason for this is that the Worker "lives" within the driver JVM process that you start when you start spark-shell and the default memory used for that is 512M.May 24, 2023 · scala.MatchError: java.lang.OutOfMemoryError: Java heap space (of class java.lang.OutOfMemoryError) Cause. This issue is often caused by a lack of resources when opening large spark-event files. The Spark heap size is set to 1 GB by default, but large Spark event files may require more than this.
Nov 7, 2019 · Please reference this forum thread in the subject: “Azure Databricks Spark: java.lang.OutOfMemoryError: GC overhead limit exceeded”. Thank you for your persistence. Proposed as answer by CHEEKATLAPRADEEP-MSFT Microsoft employee Thursday, November 7, 2019 9:20 AM . Admin header
1 Answer. The memory allocation to executors is useless here (since local just runs threads on the driver) as is the core allocations (As far as I can remember i5 doesn't have 5000 cores :)). Increase the number of partitions using spark.sql.shuffle.partitions to reduce memory pressure.Exception in thread thread_name: java.lang.OutOfMemoryError: GC Overhead limit exceeded 原因: 「GC overhead limit exceeded」という詳細メッセージは、ガベージ・コレクタが常時実行されているため、Javaプログラムの処理がほとんど進んでいないことを示しています。 It's always better to deploy each web application into their own tomcat instance, because it not only reduce memory overhead but also prevent other application from crashing due to one application hit by large requests. To avoid "java.lang.OutOfMemoryError: GC overhead limit exceeded" in Eclipse, close open process, unused files etc.Oct 17, 2013 · 7. I am getting a java.lang.OutOfMemoryError: GC overhead limit exceeded exception when I try to run the program below. This program's main method access' a specified directory and iterates over all the files that contain .xlsx. This works fine as I tested it before any of the other logic. We have a spark SQL query that returns over 5 million rows. Collecting them all for processing results in java.lang.OutOfMemoryError: GC overhead limit exceeded (eventually).Sep 16, 2022 · – java.lang.OutOfMemoryError: GC overhead limit exceeded – org.apache.spark.shuffle.FetchFailedException Possible Causes and Solutions An executor might have to deal with partitions requiring more memory than what is assigned. Consider increasing the –executor memory or the executor memory overhead to a suitable value for your application. Nov 13, 2018 · I have some data on postgres and trying to read that data on spark dataframe but i get error java.lang.OutOfMemoryError: GC overhead limit exceeded. I am using ... GC Overhead limit exceeded exceptions disappeared. However, we still had the Java heap space OOM errors to solve . Our next step was to look at our cluster health to see if we could get any clues.The detail message "GC overhead limit exceeded" indicates that the garbage collector is running all the time and Java program is making very slow progress. Can be fixed in 2 ways 1) By Suppressing GC Overhead limit warning in JVM parameter Ex- -Xms1024M -Xmx2048M -XX:+UseConcMarkSweepGC -XX:-UseGCOverheadLimit. Apr 14, 2020 · When calling on the read operation, spark first does a step where it lists all underlying files in S3, which is executed successfully. After this it does an initial load of all the data to construct a composite json schema for all files. I'm trying to process, 10GB of data using spark it is giving me this error, java.lang.OutOfMemoryError: GC overhead limit exceeded. Laptop configuration is: 4CPU, 8 logical cores, 8GB RAM. Spark configuration while submitting the spark job.The first approach works fine, the second ends up in another java.lang.OutOfMemoryError, this time about the heap. So, question: is there any programmatic alternative to this, for the particular use case (i.e., several small HashMap objects)?The first approach works fine, the second ends up in another java.lang.OutOfMemoryError, this time about the heap. So, question: is there any programmatic alternative to this, for the particular use case (i.e., several small HashMap objects)?Feb 5, 2019 · Sorted by: 1. The difference was in available memory for driver. I found out it by zeppelin-interpreter-spark.log: memorystore started with capacity .... When I used bult-in spark it was 2004.6 MB for external spark it was 366.3 MB. So, I increased available memory for driver by setting spark.driver.memory in zeppelin gui. It solved the problem. GC Overhead limit exceeded exceptions disappeared. However, we still had the Java heap space OOM errors to solve . Our next step was to look at our cluster health to see if we could get any clues.Hive's OrcInputFormat has three (basically two) strategies for split calculation: BI — it is set for small fast queries where you don't want to spend very much time in split calculations and it just reads the blocks and splits blindly based on HDFS blocks and it deals with it after that. ETL — is for large queries that one it actually reads ...The first approach works fine, the second ends up in another java.lang.OutOfMemoryError, this time about the heap. So, question: is there any programmatic alternative to this, for the particular use case (i.e., several small HashMap objects)? .