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Add a test asserting that adding entries doesn't cause N queries #487

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102 changes: 100 additions & 2 deletions IFComp/t/controller_Ballot.t
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Original file line number Diff line number Diff line change
Expand Up @@ -10,15 +10,17 @@ unless ( eval q{use Test::WWW::Mechanize::Catalyst 0.55; 1} ) {
use FindBin;
use lib ("$FindBin::Bin/lib");
use IFCompTest;
use Catalyst::Test 'IFComp';
use DateTime;
use File::Copy::Recursive qw(dircopy);

my $schema = IFCompTest->init_schema();

ok( my $mech =
Test::WWW::Mechanize::Catalyst->new( catalyst_app => 'IFComp' ),
'Created mech object'
);

my $comp_dir = $schema->entry_directory;

my ($entry_id) =
$schema->storage->dbh->selectrow_array('select max(id) from entry');
$entry_id = $entry_id + 1;
Expand Down Expand Up @@ -50,4 +52,100 @@ $mech->content_contains("Your rating");

$entry->discard_changes;

# ---------------------------------------------------------------------------
# Guard against ballot N+1 queries
# ---------------------------------------------------------------------------

sub _count_ballot_queries {
my ($mech) = @_;

my $count = 0;
my $storage = IFComp->model('IFCompDB')->schema->storage;
$storage->debug(1);
$storage->debugcb(
sub {
my ( $op, $info ) = @_;
my $msg
= !defined $info ? ( $op // '' )
: ref($info) ? ( $info->{sql} // '' )
: "$info";
return unless $msg =~ /^\s*(?:SELECT|INSERT|UPDATE|DELETE)\b/i;
$count++;
}
);

$mech->get('http://localhost/ballot');
$storage->debug(0);
$storage->debugcb(undef);

return $count;
}

sub _add_ballot_entries {
my ( $schema, $n ) = @_;

# Simple website entry with on-disk files we can clone.
my $donor = $schema->resultset('Entry')->find(106);
BAIL_OUT('Expected fixture entry 106 to exist') unless $donor;

for my $i ( 1 .. $n ) {
my $new_entry = $schema->resultset('Entry')->create(
{ author => 1,
title => "Query Budget Game $i",
comp => 2,
platform => 'website',
blurb => 'n-plus-one regression fixture',
}
);
dircopy( $donor->directory->stringify,
$new_entry->directory->stringify );
$new_entry->clear_directory;
$new_entry->update_content_directory;

$schema->resultset('EntryUpdate')->create(
{ entry => $new_entry->id,
note => 'fixture update',
time => DateTime->now( time_zone => 'UTC' ),
}
);
$schema->resultset('EntryCoauthor')->create(
{ entry_id => $new_entry->id,
coauthor_id => 2,
pseudonym => "Perf Coauthor $i",
reveal_pseudonym => 1,
}
);
}
}

# Count as anonymous so session/auth noise stays minimal and stable.
$mech->get('http://localhost/auth/logout');

my $queries_before = _count_ballot_queries($mech);
ok( $mech->success, 'ballot loads before adding entries' );

my $added = 15;
_add_ballot_entries( $schema, $added );

my $queries_after = _count_ballot_queries($mech);
ok( $mech->success, 'ballot loads after adding entries' );
$mech->content_contains('Query Budget Game 1');
$mech->content_contains('Query Budget Game 15');

diag(
"ballot SQL statements before=$queries_before after=$queries_after (added $added entries with coauthors+updates)"
);

# Batch loading keeps statement count flat; classic N+1 would add ~3+ per entry.
cmp_ok(
$queries_after - $queries_before,
'<=', 3,
"adding $added entries adds at most 3 SQL statements (not O(n))"
);
cmp_ok(
$queries_after, '<',
$added,
'total ballot queries stay below entry-count (N+1 would exceed this)'
);

done_testing();
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