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Posted to jira@arrow.apache.org by "Micah Kornfield (Jira)" <ji...@apache.org> on 2020/10/23 15:20:00 UTC
[jira] [Commented] (ARROW-10377) [C++][Parquet] nullptr access
violation when writing arrays of non-nullable values
[ https://issues.apache.org/jira/browse/ARROW-10377?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17219748#comment-17219748 ]
Micah Kornfield commented on ARROW-10377:
-----------------------------------------
Thanks for the report. In this case the NullableValue refers to the leaf element. So I'm not sure that is where the problem is. Investigating.
> [C++][Parquet] nullptr access violation when writing arrays of non-nullable values
> ----------------------------------------------------------------------------------
>
> Key: ARROW-10377
> URL: https://issues.apache.org/jira/browse/ARROW-10377
> Project: Apache Arrow
> Issue Type: Bug
> Affects Versions: 2.0.0
> Reporter: Tanguy Fautre
> Assignee: Micah Kornfield
> Priority: Major
>
> I'm updating ParquetSharp to build against Arrow 2.0.0 (currently using Arrow 1.0.1). One of our unit test is now throwing a {{nullptr}} access violation.
> I have narrowed it down to writing arrays of non-nullable values (in this case the column contains {{int[]}}) . If the values are nullable, the test passes.
> The parquet file schema is as following:
> * {{GroupNode("schema", LogicalType.None, Repetition.Required)}}
> ** {{GroupNode("array_of_ints_column", LogicalType.List, Repetition.Optional)}}
> *** {{GroupNode("list", LogicalType.None, Repetition.Repeated)}}
> **** {{PrimitiveNode("item", LogicalType.Int(32, signed), Repetition.Required)}}
> The test crashes when calling {{TypedColumnWriter::WriteBatchSpaced}} with the following arguments:
> * {{num_values = 1}}
> * {{def_levels = {0}}}
> * {{rep_levels = {0}}}
> * {{valid_bits = {0}}}
> * {{valid_bit_offset = 0}}
> * {{values = {}}} (i.e. {{nullptr}})
> This call is effectively trying to write a null array, and therefore (to my understanding) does not need to pass any values. Yet further down the callstack, the implementation tries to read one value out of {{values}} (which is {{nullptr}}).
> I believe the problem lies with
> {code:c++}
> void MaybeCalculateValidityBits(
> const int16_t* def_levels,
> int64_t batch_size,
> int64_t* out_values_to_write,
> int64_t* out_spaced_values_to_write,
> int64_t* null_count) {
> if (bits_buffer_ == nullptr) {
> if (!level_info_.HasNullableValues()) {
> *out_values_to_write = batch_size;
> *out_spaced_values_to_write = batch_size;
> *null_count = 0;
> } else {
> for (int x = 0; x < batch_size; x++) {
> *out_values_to_write += def_levels[x] == level_info_.def_level ? 1 : 0;
> *out_spaced_values_to_write +=
> def_levels[x] >= level_info_.repeated_ancestor_def_level ? 1 : 0;
> }
> *null_count = *out_values_to_write - *out_spaced_values_to_write;
> }
> return;
> }
> // ...
> }
> {code}
> In particular, {{level_info_.HasNullableValues()}} returns {{false}} given that the arrays cannot contain null-values. My understanding is that this is wrong, since the arrays themselves are nullable.
> This code appears to have been introduced by ARROW-9603.
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