From: Peter Rabbitson Date: Mon, 24 Aug 2009 20:50:13 +0000 (+0000) Subject: Seems like abraxxa's bug is fixed X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=d8ce00f56c1c32808bfe881e3e9c5c81867bdb35;p=dbsrgits%2FDBIx-Class-Historic.git Seems like abraxxa's bug is fixed --- diff --git a/Changes b/Changes index 14cded1..ae5c0d1 100644 --- a/Changes +++ b/Changes @@ -1,5 +1,8 @@ Revision history for DBIx::Class + - Fixed a complex prefetch + regular join regression introduced + in 0.08108 + 0.08109 2009-08-18 08:35:00 (UTC) - Replication updates: - Improved the replication tests so that they are more reliable diff --git a/lib/DBIx/Class/Storage/DBI.pm b/lib/DBIx/Class/Storage/DBI.pm index e08ff9c..be1d64d 100644 --- a/lib/DBIx/Class/Storage/DBI.pm +++ b/lib/DBIx/Class/Storage/DBI.pm @@ -1577,179 +1577,224 @@ sub _select_args { sub _adjust_select_args_for_complex_prefetch { my ($self, $from, $select, $where, $attrs) = @_; - $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute') - if (ref $from ne 'ARRAY'); - - # copies for mangling - $from = [ @$from ]; - $select = [ @$select ]; - $attrs = { %$attrs }; + $self->throw_exception ('Nothing to prefetch... how did we get here?!') + if not @{$attrs->{_prefetch_select}}; - # separate attributes - my $sub_attrs = { %$attrs }; - delete $attrs->{$_} for qw/where bind rows offset group_by having/; - delete $sub_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/; + $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute') + if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY'); - my $select_root_alias = $attrs->{alias}; - my $sql_maker = $self->sql_maker; - # create subquery select list - consider only stuff *not* brought in by the prefetch - my $sub_select = []; - my $sub_group_by; - for my $i (0 .. @{$attrs->{select}} - @{$attrs->{_prefetch_select}} - 1) { - my $sel = $attrs->{select}[$i]; + # generate inner/outer attribute lists, remove stuff that doesn't apply + my $outer_attrs = { %$attrs }; + delete $outer_attrs->{$_} for qw/where bind rows offset group_by having/; - # alias any functions to the dbic-side 'as' label - # adjust the outer select accordingly - if (ref $sel eq 'HASH' ) { - $sel->{-as} ||= $attrs->{as}[$i]; - $select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "select_$i") ); - } + my $inner_attrs = { %$attrs }; + delete $inner_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/; - push @$sub_select, $sel; - } # bring over all non-collapse-induced order_by into the inner query (if any) # the outer one will have to keep them all - delete $sub_attrs->{order_by}; - if (my $ord_cnt = @{$attrs->{order_by}} - @{$attrs->{_collapse_order_by}} ) { - $sub_attrs->{order_by} = [ - @{$attrs->{order_by}}[ 0 .. $ord_cnt - 1] + delete $inner_attrs->{order_by}; + if (my $ord_cnt = @{$outer_attrs->{order_by}} - @{$outer_attrs->{_collapse_order_by}} ) { + $inner_attrs->{order_by} = [ + @{$outer_attrs->{order_by}}[ 0 .. $ord_cnt - 1] ]; } - # mangle {from}, keep in mind that $from is "headless" from here on - my $join_root = shift @$from; - my %inner_joins; - my %join_info = map { $_->[0]{-alias} => $_->[0] } (@$from); + # generate the inner/outer select lists + # for inside we consider only stuff *not* brought in by the prefetch + # on the outside we substitute any function for its alias + my $outer_select = [ @$select ]; + my $inner_select = []; + for my $i (0 .. ( @$outer_select - @{$outer_attrs->{_prefetch_select}} - 1) ) { + my $sel = $outer_select->[$i]; + + if (ref $sel eq 'HASH' ) { + $sel->{-as} ||= $attrs->{as}[$i]; + $outer_select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "inner_column_$i") ); + } + + push @$inner_select, $sel; + } + + # normalize a copy of $from, so it will be easier to work with further + # down (i.e. promote the initial hashref to an AoH) + $from = [ @$from ]; + $from->[0] = [ $from->[0] ]; + my %original_join_info = map { $_->[0]{-alias} => $_->[0] } (@$from); - # in complex search_related chains $select_root_alias may *not* be - # 'me' so always include it in the inner join - $inner_joins{$select_root_alias} = 1 if ($join_root->{-alias} ne $select_root_alias); + # decide which parts of the join will remain in either part of + # the outer/inner query - # decide which parts of the join will remain on the inside - # - # this is not a very viable optimisation, but it was written - # before I realised this, so might as well remain. We can throw - # away _any_ branches of the join tree that are: - # 1) not mentioned in the condition/order - # 2) left-join leaves (or left-join leaf chains) - # Most of the join conditions will not satisfy this, but for real - # complex queries some might, and we might make some RDBMS happy. - # - # - # since we do not have introspectable SQLA, we fall back to ugly - # scanning of raw SQL for WHERE, and for pieces of ORDER BY - # in order to determine what goes into %inner_joins + # First we compose a list of which aliases are used in restrictions + # (i.e. conditions/order/grouping/etc). Since we do not have + # introspectable SQLA, we fall back to ugly scanning of raw SQL for + # WHERE, and for pieces of ORDER BY in order to determine which aliases + # need to appear in the resulting sql. # It may not be very efficient, but it's a reasonable stop-gap + # Also unqualified column names will not be considered, but more often + # than not this is actually ok + # + # In the same loop we enumerate part of the selection aliases, as + # it requires the same sqla hack for the time being + my ($restrict_aliases, $select_aliases, $prefetch_aliases); { # produce stuff unquoted, so it can be scanned + my $sql_maker = $self->sql_maker; local $sql_maker->{quote_char}; my $sep = $self->_sql_maker_opts->{name_sep} || '.'; $sep = "\Q$sep\E"; - my @order_by = (map + my $non_prefetch_select_sql = $sql_maker->_recurse_fields ($inner_select); + my $prefetch_select_sql = $sql_maker->_recurse_fields ($outer_attrs->{_prefetch_select}); + my $where_sql = $sql_maker->where ($where); + my $group_by_sql = $sql_maker->_order_by({ + map { $_ => $inner_attrs->{$_} } qw/group_by having/ + }); + my @non_prefetch_order_by_chunks = (map { ref $_ ? $_->[0] : $_ } - $sql_maker->_order_by_chunks ($sub_attrs->{order_by}) + $sql_maker->_order_by_chunks ($inner_attrs->{order_by}) ); - my $where_sql = $sql_maker->where ($where); - my $select_sql = $sql_maker->_recurse_fields ($sub_select); - # sort needed joins - for my $alias (keys %join_info) { + for my $alias (keys %original_join_info) { + my $seen_re = qr/\b $alias $sep/x; - # any table alias found on a column name in where or order_by - # gets included in %inner_joins - # Also any parent joins that are needed to reach this particular alias - for my $piece ($select_sql, $where_sql, @order_by ) { - if ($piece =~ /\b $alias $sep/x) { - $inner_joins{$alias} = 1; + for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) { + if ($piece =~ $seen_re) { + $restrict_aliases->{$alias} = 1; } } + + if ($non_prefetch_select_sql =~ $seen_re) { + $select_aliases->{$alias} = 1; + } + + if ($prefetch_select_sql =~ $seen_re) { + $prefetch_aliases->{$alias} = 1; + } + } } - # scan for non-leaf/non-left joins and mark as needed - # also mark all ancestor joins that are needed to reach this particular alias - # (e.g. join => { cds => 'tracks' } - tracks will bring cds too ) - # - # traverse by the size of the -join_path i.e. reverse depth first - for my $alias (sort { @{$join_info{$b}{-join_path}} <=> @{$join_info{$a}{-join_path}} } (keys %join_info) ) { - - my $j = $join_info{$alias}; - $inner_joins{$alias} = 1 if (! $j->{-join_type} || ($j->{-join_type} !~ /^left$/i) ); + # Add any non-left joins to the restriction list (such joins are indeed restrictions) + for my $j (values %original_join_info) { + my $alias = $j->{-alias} or next; + $restrict_aliases->{$alias} = 1 if ( + (not $j->{-join_type}) + or + ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi) + ); + } - if ($inner_joins{$alias}) { - $inner_joins{$_} = 1 for (@{$j->{-join_path}}); + # mark all join parents as mentioned + # (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too ) + for my $collection ($restrict_aliases, $select_aliases) { + for my $alias (keys %$collection) { + $collection->{$_} = 1 + for (@{ $original_join_info{$alias}{-join_path} || [] }); } } # construct the inner $from for the subquery - my $inner_from = [ $join_root ]; + my %inner_joins = (map { %{$_ || {}} } ($restrict_aliases, $select_aliases) ); + my @inner_from; for my $j (@$from) { - push @$inner_from, $j if $inner_joins{$j->[0]{-alias}}; + push @inner_from, $j if $inner_joins{$j->[0]{-alias}}; } # if a multi-type join was needed in the subquery ("multi" is indicated by # presence in {collapse}) - add a group_by to simulate the collapse in the subq - unless ($sub_attrs->{group_by}) { + unless ($inner_attrs->{group_by}) { for my $alias (keys %inner_joins) { # the dot comes from some weirdness in collapse # remove after the rewrite if ($attrs->{collapse}{".$alias"}) { - $sub_attrs->{group_by} ||= $sub_select; + $inner_attrs->{group_by} ||= $inner_select; last; } } } + # demote the inner_from head + $inner_from[0] = $inner_from[0][0]; + # generate the subquery my $subq = $self->_select_args_to_query ( - $inner_from, - $sub_select, + \@inner_from, + $inner_select, $where, - $sub_attrs + $inner_attrs, ); + my $subq_joinspec = { - -alias => $select_root_alias, - -source_handle => $join_root->{-source_handle}, - $select_root_alias => $subq, + -alias => $attrs->{alias}, + -source_handle => $inner_from[0]{-source_handle}, + $attrs->{alias} => $subq, }; - # Generate a new from (really just replace the join slot with the subquery) - # Before we would start the outer chain from the subquery itself (i.e. - # SELECT ... FROM (SELECT ... ) alias JOIN ..., but this turned out to be - # a bad idea for search_related, as the root of the chain was effectively - # lost (i.e. $artist_rs->search_related ('cds'... ) would result in alias - # of 'cds', which would prevent from doing things like order_by artist.*) - # See t/prefetch/via_search_related.t for a better idea + # Generate the outer from - this is relatively easy (really just replace + # the join slot with the subquery), with a major caveat - we can not + # join anything that is non-selecting (not part of the prefetch), but at + # the same time is a multi-type relationship, as it will explode the result. + # + # There are two possibilities here + # - either the join is non-restricting, in which case we simply throw it away + # - it is part of the restrictions, in which case we need to collapse the outer + # result by tackling yet another group_by to the outside of the query + + # so first generate the outer_from, up to the substitution point my @outer_from; - if ($join_root->{-alias} eq $select_root_alias) { # just swap the root part and we're done - @outer_from = ( - $subq_joinspec, - @$from, - ) + while (my $j = shift @$from) { + if ($j->[0]{-alias} eq $attrs->{alias}) { # time to swap + push @outer_from, [ + $subq_joinspec, + @{$j}[1 .. $#$j], + ]; + last; # we'll take care of what's left in $from below + } + else { + push @outer_from, $j; + } } - else { # this is trickier - @outer_from = ($join_root); - - for my $j (@$from) { - if ($j->[0]{-alias} eq $select_root_alias) { - push @outer_from, [ - $subq_joinspec, - @{$j}[1 .. $#$j], - ]; - } - else { - push @outer_from, $j; - } + + # see what's left - throw away if not selecting/restricting + # also throw in a group_by if restricting to guard against + # cross-join explosions + # + while (my $j = shift @$from) { + my $alias = $j->[0]{-alias}; + + if ($select_aliases->{$alias} || $prefetch_aliases->{$alias}) { + push @outer_from, $j; + } + elsif ($restrict_aliases->{$alias}) { + push @outer_from, $j; + + # FIXME - this should be obviated by SQLA2, as I'll be able to + # have restrict_inner and restrict_outer... or something to that + # effect... I think... + + # FIXME2 - I can't find a clean way to determine if a particular join + # is a multi - instead I am just treating everything as a potential + # explosive join (ribasushi) + # + # if (my $handle = $j->[0]{-source_handle}) { + # my $rsrc = $handle->resolve; + # ... need to bail out of the following if this is not a multi, + # as it will be much easier on the db ... + + $outer_attrs->{group_by} ||= $outer_select; + # } } } + # demote the outer_from head + $outer_from[0] = $outer_from[0][0]; + # This is totally horrific - the $where ends up in both the inner and outer query # Unfortunately not much can be done until SQLA2 introspection arrives, and even # then if where conditions apply to the *right* side of the prefetch, you may have @@ -1757,7 +1802,7 @@ sub _adjust_select_args_for_complex_prefetch { # the outer select to exclude joins you didin't want in the first place # # OTOH it can be seen as a plus: (notes that this query would make a DBA cry ;) - return (\@outer_from, $select, $where, $attrs); + return (\@outer_from, $outer_select, $where, $outer_attrs); } sub _resolve_ident_sources { diff --git a/t/prefetch/grouped.t b/t/prefetch/grouped.t index 8c29115..501b250 100644 --- a/t/prefetch/grouped.t +++ b/t/prefetch/grouped.t @@ -272,15 +272,42 @@ for ($cd_rs->all) { } { - $schema->storage->debug(1); - my $cd_rs = $schema->resultset('CD')->search(undef, { + my $cd_rs = $schema->resultset('CD')->search({}, { distinct => 1, join => [qw/ tracks /], prefetch => [qw/ artist /], }); - - is($cd_rs->all, 5, 'search with has_many join and distinct ok'); - $schema->storage->debug(0); + is($cd_rs->count, 5, 'complex prefetch + non-prefetching has_many join count correct'); + is($cd_rs->all, 5, 'complex prefetch + non-prefetching has_many join number of objects correct'); + + # try the same as above, but add a condition so the tracks join can not be thrown away + my $cd_rs2 = $cd_rs->search ({ 'tracks.title' => { '!=' => 'ugabuganoexist' } }); + is($cd_rs2->count, 5, 'complex prefetch + non-prefetching restricted has_many join count correct'); + is($cd_rs2->all, 5, 'complex prefetch + non-prefetching restricted has_many join number of objects correct'); + + # the outer group_by seems like a necessary evil, if someone can figure out how to take it away + # without breaking compat - be my guest + is_same_sql_bind ( + $cd_rs2->as_query, + '( + SELECT me.cdid, me.artist, me.title, me.year, me.genreid, me.single_track, + artist.artistid, artist.name, artist.rank, artist.charfield + FROM ( + SELECT me.cdid, me.artist, me.title, me.year, me.genreid, me.single_track + FROM cd me + LEFT JOIN track tracks ON tracks.cd = me.cdid + JOIN artist artist ON artist.artistid = me.artist + WHERE ( tracks.title != ? ) + GROUP BY me.cdid, me.artist, me.title, me.year, me.genreid, me.single_track + ) me + LEFT JOIN track tracks ON tracks.cd = me.cdid + JOIN artist artist ON artist.artistid = me.artist + WHERE ( tracks.title != ? ) + GROUP BY me.cdid, me.artist, me.title, me.year, me.genreid, me.single_track, + artist.artistid, artist.name, artist.rank, artist.charfield + )', + [ map { [ 'tracks.title' => 'ugabuganoexist' ] } (1 .. 2) ], + ); } done_testing;