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https://issues.apache.org/jira/browse/HBASE-27990?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17747196#comment-17747196
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ConfX commented on HBASE-27990:
-------------------------------
Hi [~wchevreuil],
Thanks for the response! The system should indeed crash when 0 is configured.
However, the system should not crash due to an unhandled Arithmetic Exception,
which can be dangerous and uninformative. We believe that a better way of
handling this is adding a precheck, just like what is done in the the
constructor of the exact same class several lines later:
{code:java}
if (blockNumCapacity >= Integer.MAX_VALUE) {
// Enough for about 32TB of cache!
throw new IllegalArgumentException("Cache capacity is too large, only
support 32TB now");
}
{code}
and
{code:java}
private void sanityCheckConfigs() {
Preconditions.checkArgument(acceptableFactor <= 1 && acceptableFactor >= 0,
ACCEPT_FACTOR_CONFIG_NAME + " must be between 0.0 and 1.0");
...
{code}
We have also provided an easy patch of this issue. [^HBASE-27990.patch]
> BucketCache causes ArithmeticException due to improper blockSize value
> checking
> --------------------------------------------------------------------------------
>
> Key: HBASE-27990
> URL: https://issues.apache.org/jira/browse/HBASE-27990
> Project: HBase
> Issue Type: Bug
> Reporter: ConfX
> Priority: Critical
> Attachments: HBASE-27990.patch, reproduce.sh
>
>
> h2. What happened
> There is no value checking for parameter
> {{{}hbase.blockcache.minblocksize{}}}. This may cause improper calculations
> and crashes the system like division by 0.
> h2. Buggy code
> In {{{}BucketCache.java{}}}, there is no value checking for {{blockSize}} and
> this variable is directly used to calculate the {{{}blockNumCapacity{}}}.
> When {{blockSize}} is mistakenly set to 0, the code would cause division by 0
> and throw ArithmeticException to crash the system.
> {noformat}
> public BucketCache(String ioEngineName, long capacity, int blockSize, int[]
> bucketSizes,
> int writerThreadNum, int writerQLen, String persistencePath, int
> ioErrorsTolerationDuration,
> Configuration conf) throws IOException {
> ...
> long blockNumCapacity = capacity / blockSize;
> ...{noformat}
> h2. How to reproduce
> (1) set hbase.blockcache.minblocksize=0
> (2) run
> org.apache.hadoop.hbase.io.hfile.TestCacheConfig#testBucketCacheConfigL1L2Setup
> you should observe the following failure:
> {noformat}
> java.lang.ArithmeticException: / by zero
> at
> org.apache.hadoop.hbase.io.hfile.bucket.BucketCache.<init>(BucketCache.java:282)
> at
> org.apache.hadoop.hbase.io.hfile.BlockCacheFactory.createBucketCache(BlockCacheFactory.java:238)
> at
> org.apache.hadoop.hbase.io.hfile.BlockCacheFactory.createBlockCache(BlockCacheFactory.java:110)
> at
> org.apache.hadoop.hbase.io.hfile.TestCacheConfig.testBucketCacheConfigL1L2Setup(TestCacheConfig.java:325)
> ...{noformat}
> For an easy reproduction, run the reproduce.sh in the attachment.
> We are happy to provide a patch if this issue is confirmed.
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