Re: Unicode database + JDBC driver performance

On Sat, Dec 21, 2002 at 03:33:57PM -0500, Tom Lane wrote:
> If no translation is happening then I can't see a reason for any
> difference at all, given what you were doing.
>
> I can imagine speed differences for operations that actually interpret
> the character data --- for example, sorting on a text column --- but
> AFAICT you weren't doing anything like that.
>
> It'd be worth checking first to see whether the extra time is really
> being spent in the backend, client, or both.

Hello,

Here are the results of the more detailed benchmarks.

Legend: the left column is "utime", right column is "stime" (both in
jiffies) according to "cat /proc/<pid>/stat" output for the 'postgres'
process created by establishing the database connection. For the client,
I used the Unix 'time' command (and assumed 1 jiffie == 1/100s).

In short, we can see that the backend's performance is somewhat worse
for the Unicode database in the INSERT benchmark. The client's
(driver's) performance is much worse for Unicode in this same
benchmark.

In the SELECT benchmark, the backend performance does not vary
between UNICODE and LATIN1 (nice!). The difference in client's
performance is even bigger than in the INSERT benchmark, though.

It looks like the driver needs some profiling to find out the reason.

Thanks for your assistance.

-JPL


INSERT benchmark

backend
LATIN1      UNICODE
351 102     480 134
370 112     476 164
376 126     496 178
359 125     498 126
-------     -------
364 116     487 150     33% 29% worse

client
LATIN1      UNICODE
234  45     418  56
224  56     441  48
241  43     430  49
222  41     439  34
-------     -------
230  46     432  47     87% 2% worse


SELECT benchmark

backend
LATIN1      UNICODE
70 9        74 15
74 19       84 14
84 12       71 11
71 13       74 14
-----       -----
75 13       76 14       about the same

client
LATIN1      UNICODE
217  22     529  14
217  18     544  25
217  26     534  14
219  21     542  17
-------     -------
218  22     537  18     146% worse