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e9bd1473 |
1 | use strict; |
2 | use warnings; |
3 | |
4 | use Test::More; |
5 | use Test::Exception; |
6 | use lib qw(t/lib); |
7 | use DBICTest; |
8 | use Data::Dumper; |
9 | |
10 | my $schema = DBICTest->init_schema(); |
11 | |
12 | my $orig_debug = $schema->storage->debug; |
13 | |
14 | use IO::File; |
15 | |
16 | BEGIN { |
17 | eval "use DBD::SQLite"; |
18 | plan $@ |
19 | ? ( skip_all => 'needs DBD::SQLite for testing' ) |
20 | : ( tests => 16 ); |
21 | } |
22 | |
e9bd1473 |
23 | # once the following TODO is complete, remove the 2 warning tests immediately |
24 | # after the TODO block |
25 | # (the TODO block itself contains tests ensuring that the warns are removed) |
26 | TODO: { |
27 | local $TODO = 'Prefetch of multiple has_many rels at the same level (currently warn to protect the clueless git)'; |
28 | |
29 | #( 1 -> M + M ) |
30 | my $cd_rs = $schema->resultset('CD')->search ({ 'me.title' => 'Forkful of bees' }); |
31 | my $pr_cd_rs = $cd_rs->search ({}, { |
32 | prefetch => [qw/tracks tags/], |
33 | }); |
34 | |
35 | my $tracks_rs = $cd_rs->first->tracks; |
36 | my $tracks_count = $tracks_rs->count; |
37 | |
38 | my ($pr_tracks_rs, $pr_tracks_count); |
39 | |
40 | my $queries = 0; |
41 | $schema->storage->debugcb(sub { $queries++ }); |
42 | $schema->storage->debug(1); |
43 | |
44 | my $o_mm_warn; |
45 | { |
46 | local $SIG{__WARN__} = sub { $o_mm_warn = shift }; |
47 | $pr_tracks_rs = $pr_cd_rs->first->tracks; |
48 | }; |
49 | $pr_tracks_count = $pr_tracks_rs->count; |
50 | |
51 | ok(! $o_mm_warn, 'no warning on attempt to prefetch several same level has_many\'s (1 -> M + M)'); |
52 | |
53 | is($queries, 1, 'prefetch one->(has_many,has_many) ran exactly 1 query'); |
54 | is($pr_tracks_count, $tracks_count, 'equal count of prefetched relations over several same level has_many\'s (1 -> M + M)'); |
55 | |
56 | for ($pr_tracks_rs, $tracks_rs) { |
57 | $_->result_class ('DBIx::Class::ResultClass::HashRefInflator'); |
58 | } |
59 | |
60 | is_deeply ([$pr_tracks_rs->all], [$tracks_rs->all], 'same structure returned with and without prefetch over several same level has_many\'s (1 -> M + M)'); |
61 | |
62 | #( M -> 1 -> M + M ) |
63 | my $note_rs = $schema->resultset('LinerNotes')->search ({ notes => 'Buy Whiskey!' }); |
64 | my $pr_note_rs = $note_rs->search ({}, { |
65 | prefetch => { |
66 | cd => [qw/tags tracks/] |
67 | }, |
68 | }); |
69 | |
70 | my $tags_rs = $note_rs->first->cd->tags; |
71 | my $tags_count = $tags_rs->count; |
72 | |
73 | my ($pr_tags_rs, $pr_tags_count); |
74 | |
75 | $queries = 0; |
76 | $schema->storage->debugcb(sub { $queries++ }); |
77 | $schema->storage->debug(1); |
78 | |
79 | my $m_o_mm_warn; |
80 | { |
81 | local $SIG{__WARN__} = sub { $m_o_mm_warn = shift }; |
82 | $pr_tags_rs = $pr_note_rs->first->cd->tags; |
83 | }; |
84 | $pr_tags_count = $pr_tags_rs->count; |
85 | |
86 | ok(! $m_o_mm_warn, 'no warning on attempt to prefetch several same level has_many\'s (M -> 1 -> M + M)'); |
87 | |
88 | is($queries, 1, 'prefetch one->(has_many,has_many) ran exactly 1 query'); |
89 | |
90 | is($pr_tags_count, $tags_count, 'equal count of prefetched relations over several same level has_many\'s (M -> 1 -> M + M)'); |
91 | |
92 | for ($pr_tags_rs, $tags_rs) { |
93 | $_->result_class ('DBIx::Class::ResultClass::HashRefInflator'); |
94 | } |
95 | |
96 | is_deeply ([$pr_tags_rs->all], [$tags_rs->all], 'same structure returned with and without prefetch over several same level has_many\'s (M -> 1 -> M + M)'); |
97 | } |
98 | |
99 | # remove this closure once the TODO above is working |
100 | my $w; |
101 | { |
102 | local $SIG{__WARN__} = sub { $w = shift }; |
103 | |
104 | my $rs = $schema->resultset('CD')->search ({ 'me.title' => 'Forkful of bees' }, { prefetch => [qw/tracks tags/] }); |
105 | for (qw/all count next first/) { |
106 | undef $w; |
107 | my @stuff = $rs->search()->$_; |
108 | like ($w, qr/will currently disrupt both the functionality of .rs->count\(\), and the amount of objects retrievable via .rs->next\(\)/, |
109 | "warning on ->$_ attempt prefetching several same level has_manys (1 -> M + M)"); |
110 | } |
111 | my $rs2 = $schema->resultset('LinerNotes')->search ({ notes => 'Buy Whiskey!' }, { prefetch => { cd => [qw/tags tracks/] } }); |
112 | for (qw/all count next first/) { |
113 | undef $w; |
114 | my @stuff = $rs2->search()->$_; |
115 | like ($w, qr/will currently disrupt both the functionality of .rs->count\(\), and the amount of objects retrievable via .rs->next\(\)/, |
116 | "warning on ->$_ attempt prefetching several same level has_manys (M -> 1 -> M + M)"); |
117 | } |
118 | } |
87333f6c |
119 | |
120 | __END__ |
121 | The solution is to rewrite ResultSet->_collapse_result() and |
122 | ResultSource->resolve_prefetch() to focus on the final results from the collapse |
123 | of the data. Right now, the code doesn't treat the columns from the various |
124 | tables as grouped entities. While there is a concept of hierarchy (so that |
125 | prefetching down relationships does work as expected), there is no idea of what |
126 | the final product should look like and how the various columns in the row would |
127 | play together. So, the actual prefetch datastructure from the search would be |
128 | very useful in working through this problem. We already have access to the PKs |
129 | and sundry for those. So, when collapsing the search result, we know we are |
130 | looking for 1 cd object. We also know we're looking for tracks and tags records |
131 | -independently- of each other. So, we can grab the data for tracks and data for |
132 | tags separately, uniqueing on the PK as appropriate. Then, when we're done with |
133 | the given cd object's datastream, we know we're good. This should work for all |
134 | the various scenarios. |
135 | |
136 | My reccommendation is the row's data is preprocessed first, breaking it up into |
137 | the data for each of the component tables. (This could be done in the single |
138 | table case, too, but probably isn't necessary.) So, starting with something |
139 | like: |
140 | my $row = { |
141 | t1.col1 => 1, |
142 | t1.col2 => 2, |
143 | t2.col1 => 3, |
144 | t2.col2 => 4, |
145 | t3.col1 => 5, |
146 | t3.col2 => 6, |
147 | }; |
148 | it is massaged to look something like: |
149 | my $row_massaged = { |
150 | t1 => { col1 => 1, col2 => 2 }, |
151 | t2 => { col1 => 3, col2 => 4 }, |
152 | t3 => { col1 => 5, col2 => 6 }, |
153 | }; |
154 | At this point, find the stuff that's different is easy enough to do and slotting |
fec7084a |
155 | things into the right spot is, likewise, pretty straightforward. Instead of |
156 | storing things in a AoH, store them in a HoH keyed on the PKs of the the table, |
157 | then convert to an AoH after all collapsing is done. |
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158 | |
159 | This implies that the collapse attribute can probably disappear or, at the |
160 | least, be turned into a boolean (which is how it's used in every other place). |