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https://issues.apache.org/jira/browse/HUDI-4192?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17550233#comment-17550233
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Hao commented on HUDI-4192:
---------------------------
The recurrence steps are as follows:
In the HFile of attachment, including indexes of the 3 columns, which are
"dtm", "hh", and "dvce_id" sequentially. a simple reproduction code is as
follows:
{code:java}
HoodieHFileReader<GenericRecord> hfileReader =
(HoodieHFileReader<GenericRecord>) createReader(new Configuration());
List<String> keyPrefixes = new ArrayList<>();
keyPrefixes.add("YAWXdbh2gWI="); // keyprefix of "dvce_id"
keyPrefixes.add("Bkmxu5plBpg="); // keyprefix of "dtm"
Iterator<GenericRecord> iterator =
hfileReader.getRecordsByKeyPrefixIterator(keyPrefixes);
while (iterator.hasNext()) {
GenericRecord record = iterator.next(); // which will throw
NullPointerException
} {code}
> HoodieHFileReader scan the cells of Header IndexColumn throw
> NullPointerException
> ---------------------------------------------------------------------------------
>
> Key: HUDI-4192
> URL: https://issues.apache.org/jira/browse/HUDI-4192
> Project: Apache Hudi
> Issue Type: Bug
> Reporter: Hao
> Priority: Minor
> Fix For: 0.12.0
>
> Attachments: col-stats-0097_86-717-560846_20220605111639266001.hfile
>
>
> Assume we index N columns in the MetaTable, such as col_1, col_2... col_n
> When executing a query that "{*}selects * from table where col_n = 'xx' and
> col1 = 'xx'{*}"".
> In the process of scanning the hfiles of MetaTable, there are acually 2 steps:
> Firstly, the col_n cells will be scanned in the hfile (mainly to obtain the
> minmax), once the scan is completed, the scanner is already at the end of the
> file.
> Secondly, at this time when the cell of the col_1 is scanned, because the
> seekTo is not called in time to back to the file header, it will encounter
> the scanner.getCell to report the NullPointerException exception.
>
> !https://issues.apache.org/vision-file-storage/api/file/download/upload-v2/2022/5/5/h00424960/f2c6fbea023242939c3e804a280cd642/image.png!
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