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ASF GitHub Bot commented on HAWQ-155: ------------------------------------- Github user asfgit closed the pull request at: https://github.com/apache/incubator-hawq/pull/285 > 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. -- This message was sent by Atlassian JIRA (v6.3.4#6332)