[jira] [Updated] (HAWQ-155) Cross-border access

["Dong Li (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HAWQ-155?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Dong Li updated HAWQ-155:
-------------------------
    Summary: Cross-border access  (was: large tuple in )

> Cross-border access
> -------------------
>
>                 Key: HAWQ-155
>                 URL: https://issues.apache.org/jira/browse/HAWQ-155
>             Project: Apache HAWQ
>          Issue Type: Bug
>            Reporter: Dong Li
>            Assignee: Lei Chang
>
> 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}
> 	if (i > 0)
> 	{
> 	  if (storageRead->storageAttributes.version == AORelationVersion_Original)
> 	  {
> 	    i = i / 4 * 4;
> 	  }
> 	  else if (storageRead->storageAttributes.version == AORelationVersion_Aligned64bit)
> 	  {
> 	    i = i / 8 * 8;
> 	  }
> 	  *headerOffsetInFile += i;
> 	  *header += i;
> 	  storageRead->bufferedRead.bufferOffset += i;
> 	}
> 	/*
> 	 * Determine the maximum boundary of the block.
> 	 * UNDONE: When we have a block directory, we will tighten the limit down.
> 	 */
> 	fileRemainderLen = storageRead->bufferedRead.fileLen -
> 		               *headerOffsetInFile;
> 	if (storageRead->maxBufferLen > fileRemainderLen)
> 		*blockLimitLen = (int32)fileRemainderLen;
> 	else
> 		*blockLimitLen = storageRead->maxBufferLen;
> 	return (*blockLimitLen > 0);
> {code}
> The fileRemainderLen is calculated wrong. As it should be the spiltlen-*headerOffsetInFile if the isUseSplitLen is true.
> At the moment, fileLen = 268435456, splitLen = 134217728 , isUseSplitLen=0x01
> And the problem is because of a out of range access to the hdfs file.



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