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https://issues.apache.org/jira/browse/PARQUET-739?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Florian Scheibner updated PARQUET-739:
--------------------------------------
Description:
Reading two parquet files in parallel lead to a memory corruption that caused a
crash. The columns are rle dictionary encoded strings in an uncompressed page,
created with parquet-mr.
Initial debugging showed that the indices for the dictionary returned by the
rle decoder are garbage. So that data page got corrupted in memory. Reading the
files in one thread works.
I have a ColumnReader for each column and read one element from reach column to
get a complete row.
The indices are decoded into one global static buffer. So multiple threads all
use the same buffer and overwrite each other's indices.
was:
Reading two parquet files in parallel lead to a memory corruption that caused a
crash. The columns are rle dictionary encoded strings in an uncompressed page,
created with parquet-mr. -fsanitize tracked the issue to a use-after free:
{code}
=================================================================
==81678==ERROR: AddressSanitizer: heap-use-after-free on address 0x6060001088c0
at pc 0x000003dbd42b bp 0x7fffe30fbe00 sp 0x7fffe30fbdf8
READ of size 16 at 0x6060001088c0 thread T8
#0 0x3dbd42a in int
parquet::RleDecoder::GetBatchWithDict<parquet::ByteArray>(parquet::Vector<parquet::ByteArray>
const&, parquet::ByteArray*, int)
(/home/fscheibner/Snowflake/ExecPlatform/bin/snowflake+0x3dbd42a)
#1 0x3db8efa in
parquet::DictionaryDecoder<parquet::DataType<(parquet::Type::type)6>
>::Decode(parquet::ByteArray*, int)
(/home/fscheibner/Snowflake/ExecPlatform/bin/snowflake+0x3db8efa)
#2 0x3d84767 in
parquet::TypedColumnReader<parquet::DataType<(parquet::Type::type)6>
>::ReadValues(long, parquet::ByteArray*)
(/home/fscheibner/Snowflake/ExecPlatform/bin/snowflake+0x3d84767)
#3 0x3d83497 in
parquet::TypedColumnReader<parquet::DataType<(parquet::Type::type)6>
>::ReadBatch(int, short*, short*, parquet::ByteArray*, long*)
(/home/fscheibner/Snowflake/ExecPlatform/bin/snowflake+0x3d83497)
{code}
Initial debugging showed that the indices for the dictionary returned by the
rle decoder are garbage. So that data page got corrupted in memory. Reading the
files in one thread works.
I have a ColumnReader for each column and read one element from reach column to
get a complete row.
My guess is that some data buffer is freed and then later still used for
reading. I couldn't track the source yet. Any ideas [~wesmckinn]?
Summary: Rle-decoding uses static buffer that is shared accross threads
(was: Read after free with uncompressed page)
> Rle-decoding uses static buffer that is shared accross threads
> --------------------------------------------------------------
>
> Key: PARQUET-739
> URL: https://issues.apache.org/jira/browse/PARQUET-739
> Project: Parquet
> Issue Type: Bug
> Components: parquet-cpp
> Reporter: Florian Scheibner
> Assignee: Florian Scheibner
>
> Reading two parquet files in parallel lead to a memory corruption that caused
> a crash. The columns are rle dictionary encoded strings in an uncompressed
> page, created with parquet-mr.
> Initial debugging showed that the indices for the dictionary returned by the
> rle decoder are garbage. So that data page got corrupted in memory. Reading
> the files in one thread works.
> I have a ColumnReader for each column and read one element from reach column
> to get a complete row.
> The indices are decoded into one global static buffer. So multiple threads
> all use the same buffer and overwrite each other's indices.
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