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https://issues.apache.org/jira/browse/HAWQ-155?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dong Li resolved HAWQ-155.
--------------------------
Resolution: Fixed
> Out of range access to the hdfs file as scan a large tuple
> -----------------------------------------------------------
>
> Key: HAWQ-155
> URL: https://issues.apache.org/jira/browse/HAWQ-155
> Project: Apache HAWQ
> Issue Type: Bug
> Reporter: Dong Li
> Assignee: Lirong Jian
>
> This may occur when your cluster has more than one physical segments.
> 1. Set guc value "appendonly_split_write_size_mb"
> hawq config -c appendonly_split_write_size_mb -v 2
> 2.Run sql
> {code}
> set default_segment_num=1;
> create table eightbytleft_for_readsplit(str varchar) with
> (appendonly=true,blocksize=2097152,checksum=true);
> insert into eightbytleft_for_readsplit select repeat('a',2097136*63-8);
> insert into eightbytleft_for_readsplit select repeat('a',2097136*63-8);
> TRUNCATE table eightbytleft_for_readsplit ;
> insert into eightbytleft_for_readsplit select repeat('a',2097136*63-12-8);
> insert into eightbytleft_for_readsplit select repeat('a',2097136*63-12-8);
> {code}
> When run
> {code}
> select count(*) from eightbytleft_for_readsplit;
> {code}
> ERROR: Header checksum does not match. Expected 0x0 and found 0xA92A344A
> headerOffsetInFile is134217728 overallBlockLen is 0
> (cdbappendonlystorageread.c:913) (seg0 test3:31100 pid=7878)
> (dispatcher.c:1700)
> DETAIL:
> Append-Only storage header kind 0 unknown
> Scan of Append-Only Row-Oriented relation 'eightbytleft_for_readsplit'.
> Append-Only segment file
> 'hdfs://test5:9000/hawq/hawq-1447309068/16385/16532/17522/1', block header
> offset in file = 134217728, bufferCount 65
> More specifically, The two large tuple is on two appendonly_read_split, as
> each of them is 128MB-8BYTE large, and the last 8 bytes are filed with zeros.
> when a segment scan the first tuple and finish scan the tuple, it will scan
> the 8 bytes zero, as these are zeros, it skipped zeros. That is ok.
> But the code in cdbappendonlystorageread.c:731 has some problems.
> {code}
> fileRemainderLen = storageRead->bufferedRead.fileLen -
> *headerOffsetInFile;
> if (storageRead->maxBufferLen > fileRemainderLen)
> *blockLimitLen = (int32)fileRemainderLen;
> else
> *blockLimitLen = storageRead->maxBufferLen;
> return (*blockLimitLen > 0);
> {code}
> The fileRemainderLen is calculated incorrectly. As it should be the
> spiltlen-*headerOffsetInFile if the isUseSplitLen is true.
> At the moment, fileLen = 268435456, splitLen = 134217728 ,
> isUseSplitLen=0x01, *headerOffsetInFile=134217728.
> The fileRemainderLen should be 0.
> And the code causes an out of range access to the hdfs file.
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