Re: plperl vs plpgsql - Mailing list pgsql-performance

After a long battle with technology, alex@meerkatsoft.com (Alex), an earthling, wrote:
> Christopher Browne wrote:
>>After takin a swig o' Arrakan spice grog, alex@meerkatsoft.com (Alex) belched out:
>>>i am thinking about swiching to plperl as it seems to me much more
>>>flexible and easier to create functions.
>>>
>>>what is the recommended PL for postgres? or which one is most widely
>>>used / most popular?
>>>is there a performance difference between plpgsql and plperl ?
>>>
>>>
>>
>>If what you're trying to do is "munge text," pl/perl will be a whole
>>lot more suitable than pl/pgsql because it has a rich set of text
>>mungeing tools and string functions which pl/pgsql lacks.
>>
>>If you intend to do a lot of work involving reading unmunged tuples
>>from this table and that, pl/pgsql provides a much more natural
>>syntax, and will probably be a bit faster as the query processor may
>>even be able to expand some of the actions, rather than needing to
>>treat Perl code as an "opaque blob."
>>
>>I would definitely be inclined to use the more natural language for
>>the given task...

> Is there a performance difference between the two?
> which of the PL is most widely used. One problem i have with the
> plpgsql is that the quoting is really a pain.

You seem to be inclined to play the mistaken game of "Which language
is the fastest?" which encourages myopic use of bad benchmarks.

In 8.0, quoting in pl/pgsql is less of a pain, as you can use $$ as
the begin/end indicators.

Performance will always depend on what you're doing.

- If you doing heavy amounts of "text munging," Perl has highly
  optimized library routines that you're likely to be taking
  advantage of which will likely be way faster than any pl/pgsql
  equivalent.

- If you are writing "set operations," operating on table data,
  the fact that pl/pgsql won't need to 'context switch' between
  language mode and 'accessing data from the database' mode will
  probably make it a bit quicker than pl/Perl.

- If you need some sort of "ultimate fastness," then you might look to
  writing in a language that compiles to assembler so that your loops
  will run as quick and tight as possible, which would encourage
  writing stored procedures in C.  Alas, this is _way_ harder to debug
  and deploy, and errors could pretty readily destroy your database
  instance if they were sufficiently awful.

pl/pgsql is almost certainly the most widely used procedural language,
if you're into "popularity contests."

I would be very much inclined to start with whichever language makes
it the easiest to write and maintain the algorithms you plan to write.
I would only move to another language if the initial choice proved to
_systematically_ be a conspicuous bottleneck.
--
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