Add changelog entry on 90c9dd1d, 757891ed and 89203568

Sample (not ideal - could be *SO* much better ) timings from included bencher:

Before (0.0828xx):
62951 byte-long query generated (via as_query()) in: 4.975237 seconds (take 1)
62951 byte-long query generated (via as_query()) in: 4.995723 seconds (take 2)
62951 byte-long query generated (via as_query()) in: 4.964793 seconds (take 3)
62951 byte-long query generated (via as_query()) in: 4.96168 seconds (take 4)
62951 byte-long query generated (via as_query()) in: 4.991396 seconds (take 5)
62951 byte-long query generated (via as_query()) in: 4.988478 seconds (take 6)
62951 byte-long query generated (via as_query()) in: 4.977612 seconds (take 7)
62951 byte-long query generated (via as_query()) in: 4.98648 seconds (take 8)
62951 byte-long query generated (via as_query()) in: 4.999984 seconds (take 9)

After:
62951 byte-long query generated (via as_query()) in: 0.429634 seconds (take 1)
62951 byte-long query generated (via as_query()) in: 0.416169 seconds (take 2)
62951 byte-long query generated (via as_query()) in: 0.430782 seconds (take 3)
62951 byte-long query generated (via as_query()) in: 0.416879 seconds (take 4)
62951 byte-long query generated (via as_query()) in: 0.426492 seconds (take 5)
62951 byte-long query generated (via as_query()) in: 0.428975 seconds (take 6)
62951 byte-long query generated (via as_query()) in: 0.413018 seconds (take 7)
62951 byte-long query generated (via as_query()) in: 0.428731 seconds (take 8)
62951 byte-long query generated (via as_query()) in: 0.413206 seconds (take 9)

diff --git a/Changes b/Changes
index c1faad9..5eecbe8 100644 (file)
--- a/Changes
+++ b/Changes
@@ -31,6 +31,8 @@ Revision history for DBIx::Class
     * New Features
         - InflateColumn::DateTime now accepts the ecosystem-standard option
           'time_zone', in addition to the DBIC-only 'timezone' (GH#28)
+        - Massively optimised literal SQL snippet scanner - fixes all known
+          slowdowns ( in some cases 50x ) of very complex prefetch/selects
         - DBIx::Class::Optional::Dependencies now properly understands
           combinations of requirements and does the right thing with e.g.
           ->req_list_for([qw( rdbms_oracle ic_dt )]) bringing in the Oracle

diff --git a/examples/Benchmarks/benchmark_join_optimizer.pl b/examples/Benchmarks/benchmark_join_optimizer.pl
new file mode 100755 (executable)
index 0000000..68b4a50
--- /dev/null
+++ b/examples/Benchmarks/benchmark_join_optimizer.pl
@@ -0,0 +1,48 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+use Time::HiRes qw(gettimeofday tv_interval);
+use Digest::SHA 'sha1_hex';
+
+use lib 't/lib';
+BEGIN { $ENV{DBICTEST_ANFANG_DEFANG} = 1 };
+use DBICTest;
+
+my $schema = DBICTest->init_schema(
+  quote_names => 1,
+  cursor_class => 'DBIx::Class::Cursor::Cached'
+);
+
+use Cache::FileCache;
+my $c = Cache::FileCache->new({ namespace => 'SchemaClass' });
+
+for my $i (1..9) {
+
+  my $t0 = [gettimeofday];
+
+  # getting a fresh rs makes sure we do not cache anything
+  my $rs = $schema->resultset("Artist")->search({},{
+    cache_object => $c,
+    cache_for => 999999999999,
+    prefetch => {
+      cds => [
+          ( { tracks => { cd_single => { artist => { cds => { tracks => 'cd_single' } } } } } ) x 50,
+      ],
+    },
+    rows => 2,
+  });
+
+  my $q = ${$rs->as_query}->[0];
+
+  print STDERR "@{[ length $q]} byte-long query generated (via as_query() in: ".tv_interval($t0) . " seconds (take $i)\n";
+
+  # stuff below can be made even faster, but another time
+  next;
+
+  $t0 = [ gettimeofday ];
+
+  my $x = $rs->all_hri;
+  print STDERR "Got collapsed results (via HRI) in: ".tv_interval($t0) . " seconds (take $i)\n";
+}