X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBIHacks.pm;h=8a3cb0279ff273c6e23c686cfab15aaca214a439;hb=eb58c082cf9c35760d8fc199483d38c1d926b2e4;hp=95b40929cd84787330e91e5cd4d423722b469969;hpb=23b2c49b17262ecf84307c9ffba88ed38ecc90cb;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Storage/DBIHacks.pm b/lib/DBIx/Class/Storage/DBIHacks.pm index 95b4092..8a3cb02 100644 --- a/lib/DBIx/Class/Storage/DBIHacks.pm +++ b/lib/DBIx/Class/Storage/DBIHacks.pm @@ -38,21 +38,28 @@ sub _prune_unused_joins { $self->_use_join_optimizer ); - my $aliastypes = $self->_resolve_aliastypes_from_select_args($attrs); + my $orig_aliastypes = $self->_resolve_aliastypes_from_select_args($attrs); - my $orig_joins = delete $aliastypes->{joining}; - my $orig_multiplying = $aliastypes->{multiplying}; + my $new_aliastypes = { %$orig_aliastypes }; + + # we will be recreating this entirely + my @reclassify = 'joining'; # a grouped set will not be affected by amount of rows. Thus any - # {multiplying} joins can go - delete $aliastypes->{multiplying} + # purely multiplicator classifications can go + # (will be reintroduced below if needed by something else) + push @reclassify, qw(multiplying premultiplied) if $attrs->{_force_prune_multiplying_joins} or $attrs->{group_by}; + # nuke what will be recalculated + delete @{$new_aliastypes}{@reclassify}; + my @newfrom = $attrs->{from}[0]; # FROM head is always present + # recalculate what we need once the multipliers are potentially gone + # ignore premultiplies, since they do not add any value to anything my %need_joins; - - for (values %$aliastypes) { + for ( @{$new_aliastypes}{grep { $_ ne 'premultiplied' } keys %$new_aliastypes }) { # add all requested aliases $need_joins{$_} = 1 for keys %$_; @@ -68,11 +75,16 @@ sub _prune_unused_joins { ); } - return ( \@newfrom, { - multiplying => { map { $need_joins{$_} ? ($_ => $orig_multiplying->{$_}) : () } keys %$orig_multiplying }, - %$aliastypes, - joining => { map { $_ => $orig_joins->{$_} } keys %need_joins }, - } ); + # we have a new set of joiners - for everything we nuked pull the classification + # off the original stack + for my $ctype (@reclassify) { + $new_aliastypes->{$ctype} = { map + { $need_joins{$_} ? ( $_ => $orig_aliastypes->{$ctype}{$_} ) : () } + keys %{$orig_aliastypes->{$ctype}} + } + } + + return ( \@newfrom, $new_aliastypes ); } # @@ -183,10 +195,10 @@ sub _adjust_select_args_for_complex_prefetch { # construct the inner {from} and lock it in a subquery # we need to prune first, because this will determine if we need a group_by below # throw away all non-selecting, non-restricting multijoins - # (since we def. do not care about multiplication those inside the subquery) + # (since we def. do not care about multiplication of the contents of the subquery) my $inner_subq = do { - # must use it here regardless of user requests + # must use it here regardless of user requests (vastly gentler on optimizer) local $self->{_use_join_optimizer} = 1; # throw away multijoins since we def. do not care about those inside the subquery @@ -194,116 +206,36 @@ sub _adjust_select_args_for_complex_prefetch { %$inner_attrs, _force_prune_multiplying_joins => 1 }); - # uh-oh a multiplier (which is not us) left in, this is a problem + # uh-oh a multiplier (which is not us) left in, this is a problem for limits + # we will need to add a group_by to collapse the resultset for proper counts if ( - $inner_aliastypes->{multiplying} + grep { $_ ne $root_alias } keys %{ $inner_aliastypes->{multiplying} || {} } and # if there are user-supplied groups - assume user knows wtf they are up to ( ! $inner_aliastypes->{grouping} or $inner_attrs->{_grouped_by_distinct} ) - and - my @multipliers = grep { $_ ne $root_alias } keys %{$inner_aliastypes->{multiplying}} ) { - # if none of the multipliers came from an order_by (guaranteed to have been combined - # with a limit) - easy - just slap a group_by to simulate a collapse and be on our way - if ( - ! $inner_aliastypes->{ordering} - or - ! first { $inner_aliastypes->{ordering}{$_} } @multipliers - ) { + my $cur_sel = { map { $_ => 1 } @{$inner_attrs->{select}} }; - my $unprocessed_order_chunks; - ($inner_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ( - $inner_attrs, + # *possibly* supplement the main selection with pks if not already + # there, as they will have to be a part of the group_by to collapse + # things properly + my $inner_select_with_extras; + my @pks = map { "$root_alias.$_" } $root_node->{-rsrc}->primary_columns + or $self->throw_exception( sprintf + 'Unable to perform complex limited prefetch off %s without declared primary key', + $root_node->{-rsrc}->source_name, ); - - $self->throw_exception ( - 'A required group_by clause could not be constructed automatically due to a complex ' - . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable ' - . 'group_by by hand' - ) if $unprocessed_order_chunks; + for my $col (@pks) { + push @{ $inner_select_with_extras ||= [ @{$inner_attrs->{select}} ] }, $col + unless $cur_sel->{$col}++; } - else { - # We need to order by external columns and group at the same time - # so we can calculate the proper limit - # This doesn't really make sense in SQL, however from DBICs point - # of view is rather valid (order the leftmost objects by whatever - # criteria and get the offset/rows many). There is a way around - # this however in SQL - we simply tae the direction of each piece - # of the foreign order and convert them to MIN(X) for ASC or MAX(X) - # for DESC, and group_by the root columns. The end result should be - # exactly what we expect - - # supplement the main selection with pks if not already there, - # as they will have to be a part of the group_by to collapse - # things properly - my $cur_sel = { map { $_ => 1 } @{$inner_attrs->{select}} }; - - my @pks = map { "$root_alias.$_" } $root_node->{-rsrc}->primary_columns - or $self->throw_exception( sprintf - 'Unable to perform complex limited prefetch off %s without declared primary key', - $root_node->{-rsrc}->source_name, - ); - for my $col (@pks) { - push @{$inner_attrs->{select}}, $col - unless $cur_sel->{$col}++; - } - - # wrap any part of the order_by that "responds" to an ordering alias - # into a MIN/MAX - # FIXME - this code is a joke, will need to be completely rewritten in - # the DQ branch. But I need to push a POC here, otherwise the - # pesky tests won't pass - my $sql_maker = $self->sql_maker; - my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep); - my $own_re = qr/ $lquote \Q$root_alias\E $rquote $sep | \b \Q$root_alias\E $sep /x; - my @order_chunks = map { ref $_ eq 'ARRAY' ? $_ : [ $_ ] } $sql_maker->_order_by_chunks($attrs->{order_by}); - my @new_order = map { \$_ } @order_chunks; - my $inner_columns_info = $self->_resolve_column_info($inner_attrs->{from}); - - # loop through and replace stuff that is not "ours" with a min/max func - # everything is a literal at this point, since we are likely properly - # quoted and stuff - for my $i (0 .. $#new_order) { - my $chunk = $order_chunks[$i][0]; - - # skip ourselves - next if $chunk =~ $own_re; - - ($chunk, my $is_desc) = $sql_maker->_split_order_chunk($chunk); - - # maybe our own unqualified column - my $ord_bit = ( - $lquote and $sep and $chunk =~ /^ $lquote ([^$sep]+) $rquote $/x - ) ? $1 : $chunk; - - next if ( - $ord_bit - and - $inner_columns_info->{$ord_bit} - and - $inner_columns_info->{$ord_bit}{-source_alias} eq $root_alias - ); - - $new_order[$i] = \[ - sprintf( - '%s(%s)%s', - ($is_desc ? 'MAX' : 'MIN'), - $chunk, - ($is_desc ? ' DESC' : ''), - ), - @ {$order_chunks[$i]} [ 1 .. $#{$order_chunks[$i]} ] - ]; - } - $inner_attrs->{order_by} = \@new_order; - - # do not care about leftovers here - it will be all the functions - # we just created - ($inner_attrs->{group_by}) = $self->_group_over_selection ( - $inner_attrs, - ); - } + ($inner_attrs->{group_by}, $inner_attrs->{order_by}) = $self->_group_over_selection({ + %$inner_attrs, + $inner_select_with_extras ? ( select => $inner_select_with_extras ) : (), + _aliastypes => $inner_aliastypes, + }); } # we already optimized $inner_attrs->{from} above @@ -370,9 +302,7 @@ sub _adjust_select_args_for_complex_prefetch { } } qw/selecting restricting grouping ordering/; # see what's left - throw away if not selecting/restricting - # also throw in a group_by if a non-selecting multiplier, - # to guard against cross-join explosions - my $need_outer_group_by; + my $may_need_outer_group_by; while (my $j = shift @orig_from) { my $alias = $j->[0]{-alias}; @@ -383,23 +313,19 @@ sub _adjust_select_args_for_complex_prefetch { } elsif (first { $_->{$alias} } @outer_nonselecting_chains ) { push @outer_from, $j; - $need_outer_group_by ||= $outer_aliastypes->{multiplying}{$alias} ? 1 : 0; + $may_need_outer_group_by ||= $outer_aliastypes->{multiplying}{$alias} ? 1 : 0; } } - if ( $need_outer_group_by and $attrs->{_grouped_by_distinct} ) { - my $unprocessed_order_chunks; - ($outer_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ({ + # also throw in a synthetic group_by if a non-selecting multiplier, + # to guard against cross-join explosions + # the logic is somewhat fragile, but relies on the idea that if a user supplied + # a group by on their own - they know what they were doing + if ( $may_need_outer_group_by and $attrs->{_grouped_by_distinct} ) { + ($outer_attrs->{group_by}, $outer_attrs->{order_by}) = $self->_group_over_selection ({ %$outer_attrs, from => \@outer_from, }); - - $self->throw_exception ( - 'A required group_by clause could not be constructed automatically due to a complex ' - . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable ' - . 'group_by by hand' - ) if $unprocessed_order_chunks; - } # This is totally horrific - the {where} ends up in both the inner and outer query @@ -409,7 +335,6 @@ sub _adjust_select_args_for_complex_prefetch { # the outer select to exclude joins you didn'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_attrs; } @@ -434,6 +359,7 @@ sub _resolve_aliastypes_from_select_args { my $aliases_by_type; # see what aliases are there to work with + # and record who is a multiplier and who is premultiplied my $alias_list; for my $node (@{$attrs->{from}}) { @@ -443,13 +369,17 @@ sub _resolve_aliastypes_from_select_args { or next; $alias_list->{$al} = $j; - $aliases_by_type->{multiplying}{$al} ||= { -parents => $j->{-join_path}||[] } if ( + + $aliases_by_type->{multiplying}{$al} ||= { -parents => $j->{-join_path}||[] } # not array == {from} head == can't be multiplying - ( ref($node) eq 'ARRAY' and ! $j->{-is_single} ) - or - # a parent of ours is already a multiplier - ( grep { $aliases_by_type->{multiplying}{$_} } @{ $j->{-join_path}||[] } ) - ); + if ref($node) eq 'ARRAY' and ! $j->{-is_single}; + + $aliases_by_type->{premultiplied}{$al} ||= { -parents => $j->{-join_path}||[] } + # parts of the path that are not us but are multiplying + if grep { $aliases_by_type->{multiplying}{$_} } + grep { $_ ne $al } + map { values %$_ } + @{ $j->{-join_path}||[] } } # get a column to source/alias map (including unambiguous unqualified ones) @@ -575,7 +505,8 @@ sub _resolve_aliastypes_from_select_args { return $aliases_by_type; } -# This is the engine behind { distinct => 1 } +# This is the engine behind { distinct => 1 } and the general +# complex prefetch grouper sub _group_over_selection { my ($self, $attrs) = @_; @@ -597,36 +528,116 @@ sub _group_over_selection { } } - # add any order_by parts *from the main source* that are not already - # present in the group_by - # we need to be careful not to add any named functions/aggregates - # i.e. order_by => [ ... { count => 'foo' } ... ] - my @leftovers; - for ($self->_extract_order_criteria($attrs->{order_by})) { + my @order_by = $self->_extract_order_criteria($attrs->{order_by}) + or return (\@group_by, $attrs->{order_by}); + + # add any order_by parts that are not already present in the group_by + # to maintain SQL cross-compatibility and general sanity + # + # also in case the original selection is *not* unique, or in case part + # of the ORDER BY refers to a multiplier - we will need to replace the + # skipped order_by elements with their MIN/MAX equivalents as to maintain + # the proper overall order without polluting the group criteria (and + # possibly changing the outcome entirely) + + my ($leftovers, $sql_maker, @new_order_by, $order_chunks, $aliastypes); + + my $group_already_unique = $self->_columns_comprise_identifying_set($colinfos, \@group_by); + + for my $o_idx (0 .. $#order_by) { + + # if the chunk is already a min/max function - there is nothing left to touch + next if $order_by[$o_idx][0] =~ /^ (?: min | max ) \s* \( .+ \) $/ix; + # only consider real columns (for functions the user got to do an explicit group_by) - if (@$_ != 1) { - push @leftovers, $_; - next; + my $chunk_ci; + if ( + @{$order_by[$o_idx]} != 1 + or + # only declare an unknown *plain* identifier as "leftover" if we are called with + # aliastypes to examine. If there are none - we are still in _resolve_attrs, and + # can just assume the user knows what they want + ( ! ( $chunk_ci = $colinfos->{$order_by[$o_idx][0]} ) and $attrs->{_aliastypes} ) + ) { + push @$leftovers, $order_by[$o_idx][0]; } - my $chunk = $_->[0]; - if ( - !$colinfos->{$chunk} + next unless $chunk_ci; + + # no duplication of group criteria + next if $group_index{$chunk_ci->{-fq_colname}}; + + $aliastypes ||= ( + $attrs->{_aliastypes} or - $colinfos->{$chunk}{-source_alias} ne $attrs->{alias} + $self->_resolve_aliastypes_from_select_args({ + from => $attrs->{from}, + order_by => $attrs->{order_by}, + }) + ) if $group_already_unique; + + # check that we are not ordering by a multiplier (if a check is requested at all) + if ( + $group_already_unique + and + ! $aliastypes->{multiplying}{$chunk_ci->{-source_alias}} + and + ! $aliastypes->{premultiplied}{$chunk_ci->{-source_alias}} ) { - push @leftovers, $_; - next; + push @group_by, $chunk_ci->{-fq_colname}; + $group_index{$chunk_ci->{-fq_colname}}++ } + else { + # We need to order by external columns without adding them to the group + # (eiehter a non-unique selection, or a multi-external) + # + # This doesn't really make sense in SQL, however from DBICs point + # of view is rather valid (e.g. order the leftmost objects by whatever + # criteria and get the offset/rows many). There is a way around + # this however in SQL - we simply tae the direction of each piece + # of the external order and convert them to MIN(X) for ASC or MAX(X) + # for DESC, and group_by the root columns. The end result should be + # exactly what we expect + + # FIXME - this code is a joke, will need to be completely rewritten in + # the DQ branch. But I need to push a POC here, otherwise the + # pesky tests won't pass + # wrap any part of the order_by that "responds" to an ordering alias + # into a MIN/MAX + $sql_maker ||= $self->sql_maker; + $order_chunks ||= [ + map { ref $_ eq 'ARRAY' ? $_ : [ $_ ] } $sql_maker->_order_by_chunks($attrs->{order_by}) + ]; - $chunk = $colinfos->{$chunk}{-fq_colname}; - push @group_by, $chunk unless $group_index{$chunk}++; + my ($chunk, $is_desc) = $sql_maker->_split_order_chunk($order_chunks->[$o_idx][0]); + + $new_order_by[$o_idx] = \[ + sprintf( '%s( %s )%s', + ($is_desc ? 'MAX' : 'MIN'), + $chunk, + ($is_desc ? ' DESC' : ''), + ), + @ {$order_chunks->[$o_idx]} [ 1 .. $#{$order_chunks->[$o_idx]} ] + ]; + } } - return wantarray - ? (\@group_by, (@leftovers ? \@leftovers : undef) ) - : \@group_by - ; + $self->throw_exception ( sprintf + 'A required group_by clause could not be constructed automatically due to a complex ' + . 'order_by criteria (%s). Either order_by columns only (no functions) or construct a suitable ' + . 'group_by by hand', + join ', ', map { "'$_'" } @$leftovers, + ) if $leftovers; + + # recreate the untouched order parts + if (@new_order_by) { + $new_order_by[$_] ||= \ $order_chunks->[$_] for ( 0 .. $#$order_chunks ); + } + + return ( + \@group_by, + (@new_order_by ? \@new_order_by : $attrs->{order_by} ), # same ref as original == unchanged + ); } sub _resolve_ident_sources { @@ -838,15 +849,25 @@ sub _extract_order_criteria { sub _order_by_is_stable { my ($self, $ident, $order_by, $where) = @_; - my $colinfo = $self->_resolve_column_info($ident, [ + my @cols = ( (map { $_->[0] } $self->_extract_order_criteria($order_by)), $where ? @{$self->_extract_fixed_condition_columns($where)} :(), - ]); + ) or return undef; + + my $colinfo = $self->_resolve_column_info($ident, \@cols); + + return keys %$colinfo + ? $self->_columns_comprise_identifying_set( $colinfo, \@cols ) + : undef + ; +} - return undef unless keys %$colinfo; +sub _columns_comprise_identifying_set { + my ($self, $colinfo, $columns) = @_; my $cols_per_src; - $cols_per_src->{$_->{-source_alias}}{$_->{-colname}} = $_ for values %$colinfo; + $cols_per_src -> {$_->{-source_alias}} -> {$_->{-colname}} = $_ + for grep { defined $_ } @{$colinfo}{@$columns}; for (values %$cols_per_src) { my $src = (values %$_)[0]->{-result_source};