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https://issues.apache.org/jira/browse/CASSANDRA-11053?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15167777#comment-15167777
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Adam Holmberg commented on CASSANDRA-11053:
-------------------------------------------
bq. At least for the time being I decided to look directly into the CQL type
name...but I am no so sure how it would be possible with the cython extensions.
Thanks for the explanation. I also think that makes cqlsh more robust. However,
if you did want to avoid the extra complexity, there is a way to bypass Cython
deserialization when that protocol handler is in use:
{code}
del cassandra.deserializers.DesBytesType
{code}
This causes the parser to default back to the patched cqltypes.BytesType.
A few other thoughts...
*cqlshlib.formatting.get_sub_types:*
{code}
+ else:
+ if last < len(val) - 1:
+ ret.append(val[last:].strip())
{code}
This block will always run since there is no break from the loop. Consider
moving it out of the {{else}} to make this clearer?
*bin/cqlsh.Shell.print_static_result*
{code}
+ if table_meta:
+ cqltypes = [table_meta.columns[c].typestring if c in
table_meta.columns else None for c in colnames]
{code}
There is an API change in driver 3.0 (C* cqlsh 2.2+) that will impact this.
This brings us to the question of targeting 2.1. cqlsh in 2.1 was diverging
from 2.2+, and is even more so
after CASSANDRA-10513 (2.1 did not receive the driver 3.0 upgrade). I'm
interested to hear the input on whether this should go to 2.1.
*"fix progress report"*
It's part of the summary, but I don't see anything in the
[changeset|https://github.com/apache/cassandra/compare/cassandra-2.1...stef1927:11053-2.1]
related to progress reporting. I ran an identical load with 2.1.13 and noticed
that progress samples
are much less frequent on this branch (by a factor of 3). Both progressions
were roughly linear. I don't suspect this change, but just thought I'd mention
in case something unintentional happened between 2.1.13 and here.
*side note*
Unrelated to this change, but I stumbled upon an SO question at the same time
as I was reviewing this ticket:
http://stackoverflow.com/q/35632114/20688
I'm now wondering: should we be using repr, or forcing high precision when
doing copies to avoid loss of precision (or providing a precision option for
COPY FROM)?
> 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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