[Dbix-class] (no subject)

Dami Laurent (PJ) laurent.dami at justice.ge.ch
Mon Jul 2 07:33:38 GMT 2012

Hi DBIC list,

For info, I gave a talk at the French Perl Workshop 2012
about comparing DBIx::Class (DBIC) and DBIx::DataModel (DBIDM);
at this occasion I did a few benchmarks that may be worth sharing
with you :

Extract & print 2 columns from a single table (109349 rows)
  - raw DBI                    0.43 secs
  - DBIC regular              11.09 secs
  - DBIC hashref inflator     10.06 secs    
  - DBIC 'raw data' (cursor)   4.48 secs
  - DBIDM regular              4.00 secs
  - DBIDM fast statement       2.25 secs

Join 3 tables & print 4 columns from the join (113895 rows)
  - raw DBI                                     1.36 secs
  - DBIC regular                               46.70 secs
  - DBIC, join & +columns                      15.50 secs
  - DBIC, join & +columns, hashref inflator    14.17 secs
  - DBIC, join & +columns, 'raw data' (cursor)  6.59 secs
  - DBIC, prefetch                            146.29 secs
  - DBIDM regular                               5.01 secs
  - DBIDM fast statement                        3.28 secs

I was not surprised to find out that DBIC is slower
than DBIDM :-) ; however, I was quite surprised to 
find out that, among DBIC mechanisms :

a) 'HashRefInflator', often advocated as being the fast way to get
   data from DBIC, actually doesn't seem to bring any significant
b) 'prefetch', also advocated for doing speed improvements, indeed 
   does its job of sparing queries to the database, but then has  
   such a high cost in handling the retrieved data that it becomes
   the most expensive method.
c) 'cursor', which goes directly to the DBI layer and therefore
   loses all ORM features for the retrieved data, nevertheless 
   adds a significant cost over raw DBI.

Since I'm not an expert of DBIC, I may well have done something wrong
in those benchmarks; so please correct me if necessary.
The source code is at https://github.com/damil/compare-ORM

The FPW12 talk also discussed various design aspects; the slides are at

Best regards, Laurent Dami

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