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https://issues.apache.org/jira/browse/CASSANDRA-11053?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15166414#comment-15166414
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Stefania commented on CASSANDRA-11053:
--------------------------------------
bq. Can you help me understand what the issue was? It should not change return
values. I think I'm missing something.
With cython extensions this line in cqlsh no longer works:
{code}
cassandra.cqltypes.BytesType.deserialize = staticmethod(lambda byts,
protocol_version: bytearray(byts))
{code}
So it no longer returns byte arrays for blobs and I needed a way to distinguish
between blob and ascii types; they are both of type {{str}} and it may well be
that a blob contains only valid ascii bytes. At least for the time being I
decided to look directly into the CQL type name and hence the parsing for
composite types. We may want to add a new hook in the driver moving forward but
I am no so sure how it would be possible with the cython extensions.
> COPY FROM on large datasets: fix progress report and debug performance
> ----------------------------------------------------------------------
>
> Key: CASSANDRA-11053
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11053
> Project: Cassandra
> Issue Type: Bug
> Components: Tools
> Reporter: Stefania
> Assignee: Stefania
> Fix For: 2.1.x, 2.2.x, 3.0.x, 3.x
>
> Attachments: copy_from_large_benchmark.txt,
> copy_from_large_benchmark_2.txt, parent_profile.txt, parent_profile_2.txt,
> worker_profiles.txt, worker_profiles_2.txt
>
>
> Running COPY from on a large dataset (20G divided in 20M records) revealed
> two issues:
> * The progress report is incorrect, it is very slow until almost the end of
> the test at which point it catches up extremely quickly.
> * The performance in rows per second is similar to running smaller tests with
> a smaller cluster locally (approx 35,000 rows per second). As a comparison,
> cassandra-stress manages 50,000 rows per second under the same set-up,
> therefore resulting 1.5 times faster.
> See attached file _copy_from_large_benchmark.txt_ for the benchmark details.
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