Re: Performance tweaks - Mailing list pgsql-jdbc

From Alan Stange
Subject Re: Performance tweaks
Date
Msg-id 421BA8C9.8050106@rentec.com
Whole thread Raw
In response to Re: Performance tweaks  (Oliver Jowett <oliver@opencloud.com>)
Responses Re: Performance tweaks  (Oliver Jowett <oliver@opencloud.com>)
List pgsql-jdbc
Oliver Jowett wrote:

> Ken Geis wrote:
>
>> I changed the line
>>
>>         byte[][] answer = new byte[l_nf][0];
>> to
>>         byte[][] answer = new byte[l_nf][];
>>
>> This gave ~1% increase on the benchmark I was running.
>
>
> Gah?! What JVM? Aren't the two forms equivalent?

No.  They aren't.

The first is l_nf+1 objects being created (and array of byte[] with l_nf
byte[0] entries) and the second is just a single object (an array of
byte[], with null entries).

Any JVM.  It's the language definition.

-- Alan

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