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https://issues.apache.org/jira/browse/CSV-277?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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David Mollitor updated CSV-277:
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Description:
Running the Apache ORC benchmarks which has {{commons-csv}} as a dependency and
noticed the bulk of running time is in {{commons-csv}}.
I attached the VisualVM output and here is my test setup:
{code:none}
JVM: OpenJDK 64-Bit Server VM (25.292-b10, mixed mode)
Java: version 1.8.0_292, vendor Private Build
Java Home: /usr/lib/jvm/java-8-openjdk-amd64/jre
JVM Flags: <none>
{code}
I suspect this is in part because {{ExtendedBufferedReader}} extends
{{BufferedReader}}. {{BufferedReader}} is a synchronized method class which
means that every call to {{read}} requires synchronization. Usually it's not
an issue, but for {{commons-csv}}, it adds a lot of overhead because it reads
each byte one-at-a-time. So even though it's buffered, it has to go through a
synchronization processes for each byte read. It also has to perform a "jump"
into the parent class for each byte.
Nothing else stands out to me as being "slow."
was:
{{BufferedReader}} is a synchronized method class which means that every call
to {{read}} requires synchronization.
Usually it's not an issue, but for {{commons-csv}}, it adds a lot of overhead
because it reads each byte one at a time. So even though it's buffered, it
has to go through a synchronization processes for each byte read.
Change {{ExtendedBufferedReader}} to implement its own internal buffer.
> Review Lexer simpleToken for Performance
> ----------------------------------------
>
> Key: CSV-277
> URL: https://issues.apache.org/jira/browse/CSV-277
> Project: Commons CSV
> Issue Type: Improvement
> Reporter: David Mollitor
> Priority: Major
> Attachments: CSVCapture.PNG
>
>
> Running the Apache ORC benchmarks which has {{commons-csv}} as a dependency
> and noticed the bulk of running time is in {{commons-csv}}.
> I attached the VisualVM output and here is my test setup:
> {code:none}
> JVM: OpenJDK 64-Bit Server VM (25.292-b10, mixed mode)
> Java: version 1.8.0_292, vendor Private Build
> Java Home: /usr/lib/jvm/java-8-openjdk-amd64/jre
> JVM Flags: <none>
> {code}
> I suspect this is in part because {{ExtendedBufferedReader}} extends
> {{BufferedReader}}. {{BufferedReader}} is a synchronized method class which
> means that every call to {{read}} requires synchronization. Usually it's not
> an issue, but for {{commons-csv}}, it adds a lot of overhead because it reads
> each byte one-at-a-time. So even though it's buffered, it has to go through
> a synchronization processes for each byte read. It also has to perform a
> "jump" into the parent class for each byte.
> Nothing else stands out to me as being "slow."
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