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Antoine Pitrou commented on ARROW-16761: ---------------------------------------- {{OutputStream::Tell()}} would work, yes. > [C++][Python] Track bytes_written on FileWriter / WrittenFile > ------------------------------------------------------------- > > Key: ARROW-16761 > URL: https://issues.apache.org/jira/browse/ARROW-16761 > Project: Apache Arrow > Issue Type: New Feature > Components: C++, Python > Affects Versions: 8.0.0 > Reporter: Will Jones > Priority: Major > Fix For: 9.0.0 > > > For Apache Iceberg and Delta Lake tables, we need to be able to get the size > of the files written in bytes. In Iceberg, this is the required fieldĀ > {{file_size_in_bytes}} ([docs|https://iceberg.apache.org/spec/#manifests]). > In Delta, this is the required field {{size}} as part of the Add action. > I think this could be exposed on > [FileWriter|https://github.com/apache/arrow/blob/8c63788ff7d52812599a546989b7df10887cb01e/cpp/src/arrow/dataset/file_base.h#L305] > and then through that > [WrittenFile|https://github.com/apache/arrow/blob/8c63788ff7d52812599a546989b7df10887cb01e/python/pyarrow/_dataset.pyx#L766-L769]. > But lower-level than that I'm not yet sure. {{FileWriter}} owns its > {{OutputStream}}; would {{OutputStream::Tell()}} give the correct count? -- This message was sent by Atlassian Jira (v8.20.7#820007)