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https://issues.apache.org/jira/browse/AVRO-1720?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16096128#comment-16096128
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Janosch Woschitz commented on AVRO-1720:
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Just as a follow-up since there seems to be not much progress on this ticket:
for the moment I made a separate binary available which allows efficient and
convenient counting of records contained in a single avro file or in a folder
containing several avro files.
The binaries, documentation and source are available here:
https://github.com/jwoschitz/avrocount
This project tries to fill this gap (at least) until a similar functionality is
provided by avro-tools. Over time there were also several improvements to this
project in comparison to the original patch.
It would be great if these improvements would also find a way back into the
Apache Avro project in the longterm. Until then this project can be used in
addition to the currently existing avro-tools.
> Add an avro-tool to count records in an avro file
> -------------------------------------------------
>
> Key: AVRO-1720
> URL: https://issues.apache.org/jira/browse/AVRO-1720
> Project: Avro
> Issue Type: New Feature
> Components: java
> Reporter: Janosch Woschitz
> Priority: Minor
> Labels: starter
> Attachments: AVRO-1720.patch, AVRO-1720-with-extended-unittests.patch
>
>
> If you're dealing with bigger avro files (>100MB) it would be nice to have a
> way to quickly count the amount of records contained within that file.
> With the current state of avro-tools the only way to achieve this (to my
> current knowledge) is to dump the data to json and count the amount of
> records. For bigger files this might take a while due to the serialization
> overhead and since every record needs to be looked at.
> I added a new tool which is optimized for counting records, it does not
> serialize the records and reads only the block count for each block.
> {panel:title=Naive benchmark}
> {noformat}
> # the input file had a size of ~300MB
> $ du -sh sample.avro
> 323M sample.avro
> # using the new count tool
> $ time java -jar avro-tools.jar count sample.avro
> 331439
> real 0m4.670s
> user 0m6.167s
> sys 0m0.513s
> # the current way of counting records
> $ time java -jar avro-tools.jar tojson sample.avro | wc
> 331439 54904484 1838231743
> real 0m52.760s
> user 1m42.317s
> sys 0m3.209s
> # the overhead of wc is rather minor
> $ time java -jar avro-tools.jar tojson sample.avro > /dev/null
> real 0m47.834s
> user 0m53.317s
> sys 0m1.194s
> {noformat}
> {panel}
> This tool uses the HDFS API to handle files from any supported filesystem. I
> added the unit tests to the already existing TestDataFileTools since it
> provided convenient utility functions which I could reuse for my test
> scenarios.
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