X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBIHacks.pm;h=4c54e2c42139e34ea35ababf4ac72d3958a4e170;hb=4a0eed52f392b2e135385d0c06b06160200f3772;hp=45131c715c32f5541c951c8798e97ae356b5a6e7;hpb=e39f188a9633a5f36768c806ebdb8b663d0a5809;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Storage/DBIHacks.pm b/lib/DBIx/Class/Storage/DBIHacks.pm index 45131c7..4c54e2c 100644 --- a/lib/DBIx/Class/Storage/DBIHacks.pm +++ b/lib/DBIx/Class/Storage/DBIHacks.pm @@ -4,7 +4,7 @@ package #hide from PAUSE # # This module contains code that should never have seen the light of day, # does not belong in the Storage, or is otherwise unfit for public -# display. The arrival of SQLA2 should immediately oboslete 90% of this +# display. The arrival of SQLA2 should immediately obsolete 90% of this # use strict; @@ -15,6 +15,7 @@ use mro 'c3'; use List::Util 'first'; use Scalar::Util 'blessed'; +use Sub::Name 'subname'; use namespace::clean; # @@ -33,75 +34,109 @@ sub _prune_unused_joins { my $aliastypes = $self->_resolve_aliastypes_from_select_args(@_); + my $orig_joins = delete $aliastypes->{joining}; + my $orig_multiplying = $aliastypes->{multiplying}; + # a grouped set will not be affected by amount of rows. Thus any # {multiplying} joins can go - delete $aliastypes->{multiplying} if $attrs->{group_by}; + delete $aliastypes->{multiplying} + if $attrs->{_force_prune_multiplying_joins} or $attrs->{group_by}; my @newfrom = $from->[0]; # FROM head is always present my %need_joins; + for (values %$aliastypes) { # add all requested aliases $need_joins{$_} = 1 for keys %$_; # add all their parents (as per joinpath which is an AoH { table => alias }) - $need_joins{$_} = 1 for map { values %$_ } map { @$_ } values %$_; + $need_joins{$_} = 1 for map { values %$_ } map { @{$_->{-parents}} } values %$_; } + for my $j (@{$from}[1..$#$from]) { push @newfrom, $j if ( - (! $j->[0]{-alias}) # legacy crap + (! defined $j->[0]{-alias}) # legacy crap || $need_joins{$j->[0]{-alias}} ); } - return \@newfrom; + return ( \@newfrom, { + multiplying => { map { $need_joins{$_} ? ($_ => $orig_multiplying->{$_}) : () } keys %$orig_multiplying }, + %$aliastypes, + joining => { map { $_ => $orig_joins->{$_} } keys %need_joins }, + } ); } # # This is the code producing joined subqueries like: -# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ... +# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ... # sub _adjust_select_args_for_complex_prefetch { my ($self, $from, $select, $where, $attrs) = @_; - $self->throw_exception ('Nothing to prefetch... how did we get here?!') - if not @{$attrs->{_prefetch_selector_range}}; - $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 $root_alias = $attrs->{alias}; # 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/; + delete @{$outer_attrs}{qw(where bind rows offset group_by _grouped_by_distinct having)}; my $inner_attrs = { %$attrs }; - delete $inner_attrs->{$_} for qw/for collapse _prefetch_selector_range _collapse_order_by select as/; + delete @{$inner_attrs}{qw(from for collapse select as _related_results_construction)}; - - # bring over all non-collapse-induced order_by into the inner query (if any) - # the outer one will have to keep them all - 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] - ]; - } + # there is no point of ordering the insides if there is no limit + delete $inner_attrs->{order_by} if ( + delete $inner_attrs->{_order_is_artificial} + or + ! $inner_attrs->{rows} + ); # 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 = []; + my $inner_select; + + my ($root_node, $root_node_offset); + + for my $i (0 .. $#$from) { + my $node = $from->[$i]; + my $h = (ref $node eq 'HASH') ? $node + : (ref $node eq 'ARRAY' and ref $node->[0] eq 'HASH') ? $node->[0] + : next + ; + + if ( ($h->{-alias}||'') eq $root_alias and $h->{-rsrc} ) { + $root_node = $h; + $root_node_offset = $i; + last; + } + } + + $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute') + unless $root_node; - my ($p_start, $p_end) = @{$outer_attrs->{_prefetch_selector_range}}; - for my $i (0 .. $p_start - 1, $p_end + 1 .. $#$outer_select) { + # use the heavy duty resolver to take care of aliased/nonaliased naming + my $colinfo = $self->_resolve_column_info($from); + my $selected_root_columns; + + for my $i (0 .. $#$outer_select) { my $sel = $outer_select->[$i]; + next if ( + $colinfo->{$sel} and $colinfo->{$sel}{-source_alias} ne $root_alias + ); + if (ref $sel eq 'HASH' ) { $sel->{-as} ||= $attrs->{as}[$i]; - $outer_select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "inner_column_$i") ); + $outer_select->[$i] = join ('.', $root_alias, ($sel->{-as} || "inner_column_$i") ); + } + elsif (! ref $sel and my $ci = $colinfo->{$sel}) { + $selected_root_columns->{$ci->{-colname}} = 1; } push @$inner_select, $sel; @@ -109,48 +144,164 @@ sub _adjust_select_args_for_complex_prefetch { push @{$inner_attrs->{as}}, $attrs->{as}[$i]; } + # We will need to fetch all native columns in the inner subquery, which may + # be a part of an *outer* join condition, or an order_by (which needs to be + # preserved outside) + # We can not just fetch everything because a potential has_many restricting + # join collapse *will not work* on heavy data types. + my $connecting_aliastypes = $self->_resolve_aliastypes_from_select_args( + $from, + [], + $where, + $inner_attrs + ); + + for (sort map { keys %{$_->{-seen_columns}||{}} } map { values %$_ } values %$connecting_aliastypes) { + my $ci = $colinfo->{$_} or next; + if ( + $ci->{-source_alias} eq $root_alias + and + ! $selected_root_columns->{$ci->{-colname}}++ + ) { + # adding it to both to keep limits not supporting dark selectors happy + push @$inner_select, $ci->{-fq_colname}; + push @{$inner_attrs->{as}}, $ci->{-fq_colname}; + } + } + # 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 - # the fake group_by is so that the pruner throws away all non-selecting, non-restricting - # multijoins (since we def. do not care about those inside the subquery) - + # throw away all non-selecting, non-restricting multijoins + # (since we def. do not care about multiplication those inside the subquery) my $inner_subq = do { # must use it here regardless of user requests local $self->{_use_join_optimizer} = 1; - my $inner_from = $self->_prune_unused_joins ($from, $inner_select, $where, { - group_by => ['dummy'], %$inner_attrs, + # throw away multijoins since we def. do not care about those inside the subquery + my ($inner_from, $inner_aliastypes) = $self->_prune_unused_joins ($from, $inner_select, $where, { + %$inner_attrs, _force_prune_multiplying_joins => 1 }); - my $inner_aliastypes = - $self->_resolve_aliastypes_from_select_args( $inner_from, $inner_select, $where, $inner_attrs ); - - # we need to simulate collapse in the subq if a multiplying join is pulled - # by being a non-selecting restrictor + # uh-oh a multiplier (which is not us) left in, this is a problem if ( - ! $inner_attrs->{group_by} + $inner_aliastypes->{multiplying} and - first { - $inner_aliastypes->{restricting}{$_} - and - ! $inner_aliastypes->{selecting}{$_} - } ( keys %{$inner_aliastypes->{multiplying}||{}} ) + # 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}} ) { - my $unprocessed_order_chunks; - ($inner_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ( - $inner_from, $inner_select, $inner_attrs->{order_by} - ); - - $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; + + # 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 $unprocessed_order_chunks; + ($inner_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ({ + %$inner_attrs, + from => $inner_from, + select => $inner_select, + }); + + $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; + } + 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_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_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_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, + from => $inner_from, + select => $inner_select, + }); + } } # we already optimized $inner_from above - local $self->{_use_join_optimizer} = 0; + # and already local()ized + $self->{_use_join_optimizer} = 0; # generate the subquery $self->_select_args_to_query ( @@ -171,39 +322,44 @@ sub _adjust_select_args_for_complex_prefetch { # - 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 + # work on a shallow copy $from = [ @$from ]; - # so first generate the outer_from, up to the substitution point my @outer_from; - while (my $j = shift @$from) { - $j = [ $j ] unless ref $j eq 'ARRAY'; # promote the head-from to an AoH - if ($j->[0]{-alias} eq $attrs->{alias}) { # time to swap + # we may not be the head + if ($root_node_offset) { + # first generate the outer_from, up and including the substitution point + @outer_from = splice @$from, 0, $root_node_offset; - push @outer_from, [ - { - -alias => $attrs->{alias}, - -rsrc => $j->[0]{-rsrc}, - $attrs->{alias} => $inner_subq, - }, - @{$j}[1 .. $#$j], - ]; - last; # we'll take care of what's left in $from below - } - else { - push @outer_from, $j; - } + push @outer_from, [ + { + -alias => $root_alias, + -rsrc => $root_node->{-rsrc}, + $root_alias => $inner_subq, + }, + @{$from->[0]}[1 .. $#{$from->[0]}], + ]; + } + else { + @outer_from = { + -alias => $root_alias, + -rsrc => $root_node->{-rsrc}, + $root_alias => $inner_subq, + }; } + shift @$from; # what we just replaced above + # scan the *remaining* from spec against different attributes, and see which joins are needed # in what role - my $outer_aliastypes = + my $outer_aliastypes = $outer_attrs->{_aliastypes} = $self->_resolve_aliastypes_from_select_args( $from, $outer_select, $where, $outer_attrs ); # unroll parents - my ($outer_select_chain, $outer_restrict_chain) = map { +{ - map { $_ => 1 } map { values %$_} map { @$_ } values %{ $outer_aliastypes->{$_} || {} } - } } qw/selecting restricting/; + my ($outer_select_chain, @outer_nonselecting_chains) = map { +{ + map { $_ => 1 } map { values %$_} map { @{$_->{-parents}} } values %{ $outer_aliastypes->{$_} || {} } + } } 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, @@ -217,21 +373,19 @@ sub _adjust_select_args_for_complex_prefetch { ) { push @outer_from, $j } - elsif ($outer_restrict_chain->{$alias}) { + elsif (first { $_->{$alias} } @outer_nonselecting_chains ) { push @outer_from, $j; $need_outer_group_by ||= $outer_aliastypes->{multiplying}{$alias} ? 1 : 0; } } - # demote the outer_from head - $outer_from[0] = $outer_from[0][0]; - - if ($need_outer_group_by and ! $outer_attrs->{group_by}) { - + 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 ( - \@outer_from, $outer_select, $outer_attrs->{order_by} - ); + ($outer_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ({ + %$outer_attrs, + from => \@outer_from, + select => $outer_select, + }); $self->throw_exception ( 'A required group_by clause could not be constructed automatically due to a complex ' @@ -245,7 +399,7 @@ sub _adjust_select_args_for_complex_prefetch { # 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 # to both filter the inner select (e.g. to apply a limit) and then have to re-filter - # the outer select to exclude joins you didin't want in the first place + # 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_from, $outer_select, $where, $outer_attrs); @@ -256,7 +410,7 @@ sub _adjust_select_args_for_complex_prefetch { # # Due to a lack of SQLA2 we fall back to crude scans of all the # select/where/order/group attributes, in order to determine what -# aliases are neded to fulfill the query. This information is used +# aliases are needed to fulfill the query. This information is used # throughout the code to prune unnecessary JOINs from the queries # in an attempt to reduce the execution time. # Although the method is pretty horrific, the worst thing that can @@ -280,7 +434,7 @@ sub _resolve_aliastypes_from_select_args { or next; $alias_list->{$al} = $j; - $aliases_by_type->{multiplying}{$al} ||= $j->{-join_path}||[] if ( + $aliases_by_type->{multiplying}{$al} ||= { -parents => $j->{-join_path}||[] } if ( # not array == {from} head == can't be multiplying ( ref($_) eq 'ARRAY' and ! $j->{-is_single} ) or @@ -289,7 +443,7 @@ sub _resolve_aliastypes_from_select_args { ); } - # get a column to source/alias map (including unqualified ones) + # get a column to source/alias map (including unambiguous unqualified ones) my $colinfo = $self->_resolve_column_info ($from); # set up a botched SQLA @@ -300,6 +454,7 @@ sub _resolve_aliastypes_from_select_args { local $sql_maker->{where_bind}; local $sql_maker->{group_bind}; local $sql_maker->{having_bind}; + local $sql_maker->{from_bind}; # we can't scan properly without any quoting (\b doesn't cut it # everywhere), so unless there is proper quoting set - use our @@ -323,32 +478,54 @@ sub _resolve_aliastypes_from_select_args { my $to_scan = { restricting => [ $sql_maker->_recurse_where ($where), - $sql_maker->_parse_rs_attrs ({ - map { $_ => $attrs->{$_} } (qw/group_by having/) - }), + $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} }), + ], + grouping => [ + $sql_maker->_parse_rs_attrs ({ group_by => $attrs->{group_by} }), + ], + joining => [ + $sql_maker->_recurse_from ( + ref $from->[0] eq 'ARRAY' ? $from->[0][0] : $from->[0], + @{$from}[1 .. $#$from], + ), ], selecting => [ $sql_maker->_recurse_fields ($select), - ( map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker) ), + ], + ordering => [ + map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker), ], }; # throw away empty chunks $_ = [ map { $_ || () } @$_ ] for values %$to_scan; - # first loop through all fully qualified columns and get the corresponding + # first see if we have any exact matches (qualified or unqualified) + for my $type (keys %$to_scan) { + for my $piece (@{$to_scan->{$type}}) { + if ($colinfo->{$piece} and my $alias = $colinfo->{$piece}{-source_alias}) { + $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] }; + $aliases_by_type->{$type}{$alias}{-seen_columns}{$colinfo->{$piece}{-fq_colname}} = $piece; + } + } + } + + # now loop through all fully qualified columns and get the corresponding # alias (should work even if they are in scalarrefs) for my $alias (keys %$alias_list) { my $al_re = qr/ - $lquote $alias $rquote $sep + $lquote $alias $rquote $sep (?: $lquote ([^$rquote]+) $rquote )? | - \b $alias \. + \b $alias \. ([^\s\)\($rquote]+)? /x; for my $type (keys %$to_scan) { for my $piece (@{$to_scan->{$type}}) { - $aliases_by_type->{$type}{$alias} ||= $alias_list->{$alias}{-join_path}||[] - if ($piece =~ $al_re); + if (my @matches = $piece =~ /$al_re/g) { + $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] }; + $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = "$alias.$_" + for grep { defined $_ } @matches; + } } } } @@ -358,13 +535,15 @@ sub _resolve_aliastypes_from_select_args { for my $col (keys %$colinfo) { next if $col =~ / \. /x; # if column is qualified it was caught by the above - my $col_re = qr/ $lquote $col $rquote /x; + my $col_re = qr/ $lquote ($col) $rquote /x; for my $type (keys %$to_scan) { for my $piece (@{$to_scan->{$type}}) { - if ($piece =~ $col_re) { + if ( my @matches = $piece =~ /$col_re/g) { my $alias = $colinfo->{$col}{-source_alias}; - $aliases_by_type->{$type}{$alias} ||= $alias_list->{$alias}{-join_path}||[]; + $aliases_by_type->{$type}{$alias} ||= { -parents => $alias_list->{$alias}{-join_path}||[] }; + $aliases_by_type->{$type}{$alias}{-seen_columns}{"$alias.$_"} = $_ + for grep { defined $_ } @matches; } } } @@ -373,55 +552,65 @@ sub _resolve_aliastypes_from_select_args { # Add any non-left joins to the restriction list (such joins are indeed restrictions) for my $j (values %$alias_list) { my $alias = $j->{-alias} or next; - $aliases_by_type->{restricting}{$alias} ||= $j->{-join_path}||[] if ( + $aliases_by_type->{restricting}{$alias} ||= { -parents => $j->{-join_path}||[] } if ( (not $j->{-join_type}) or ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi) ); } + for (keys %$aliases_by_type) { + delete $aliases_by_type->{$_} unless keys %{$aliases_by_type->{$_}}; + } + return $aliases_by_type; } # This is the engine behind { distinct => 1 } sub _group_over_selection { - my ($self, $from, $select, $order_by) = @_; + my ($self, $attrs) = @_; - my $rs_column_list = $self->_resolve_column_info ($from); + my $colinfos = $self->_resolve_column_info ($attrs->{from}); my (@group_by, %group_index); # the logic is: if it is a { func => val } we assume an aggregate, # otherwise if \'...' or \[...] we assume the user knows what is # going on thus group over it - for (@$select) { + for (@{$attrs->{select}}) { if (! ref($_) or ref ($_) ne 'HASH' ) { push @group_by, $_; $group_index{$_}++; - if ($rs_column_list->{$_} and $_ !~ /\./ ) { + if ($colinfos->{$_} and $_ !~ /\./ ) { # add a fully qualified version as well - $group_index{"$rs_column_list->{$_}{-source_alias}.$_"}++; + $group_index{"$colinfos->{$_}{-source_alias}.$_"}++; } } } - # add any order_by parts that are not already present in the group_by + # 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 ($self->_extract_order_criteria($order_by)) { + for ($self->_extract_order_criteria($attrs->{order_by})) { # only consider real columns (for functions the user got to do an explicit group_by) if (@$_ != 1) { push @leftovers, $_; next; } my $chunk = $_->[0]; - my $colinfo = $rs_column_list->{$chunk} or do { + + if ( + !$colinfos->{$chunk} + or + $colinfos->{$chunk}{-source_alias} ne $attrs->{alias} + ) { push @leftovers, $_; next; - }; + } - $chunk = "$colinfo->{-source_alias}.$chunk" if $chunk !~ /\./; + $chunk = $colinfos->{$chunk}{-fq_colname}; push @group_by, $chunk unless $group_index{$chunk}++; } @@ -435,14 +624,12 @@ sub _resolve_ident_sources { my ($self, $ident) = @_; my $alias2source = {}; - my $rs_alias; # the reason this is so contrived is that $ident may be a {from} # structure, specifying multiple tables to join if ( blessed $ident && $ident->isa("DBIx::Class::ResultSource") ) { # this is compat mode for insert/update/delete which do not deal with aliases $alias2source->{me} = $ident; - $rs_alias = 'me'; } elsif (ref $ident eq 'ARRAY') { @@ -450,7 +637,6 @@ sub _resolve_ident_sources { my $tabinfo; if (ref $_ eq 'HASH') { $tabinfo = $_; - $rs_alias = $tabinfo->{-alias}; } if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') { $tabinfo = $_->[0]; @@ -461,7 +647,7 @@ sub _resolve_ident_sources { } } - return ($alias2source, $rs_alias); + return $alias2source; } # Takes $ident, \@column_names @@ -473,7 +659,7 @@ sub _resolve_ident_sources { # for all sources sub _resolve_column_info { my ($self, $ident, $colnames) = @_; - my ($alias2src, $root_alias) = $self->_resolve_ident_sources($ident); + my $alias2src = $self->_resolve_ident_sources($ident); my (%seen_cols, @auto_colnames); @@ -515,7 +701,11 @@ sub _resolve_column_info { }, -result_source => $rsrc, -source_alias => $source_alias, + -fq_colname => $col eq $colname ? "$source_alias.$col" : $col, + -colname => $colname, }; + + $return{"$source_alias.$colname"} = $return{$col} if $col eq $colname; } return \%return; @@ -568,7 +758,7 @@ sub _inner_join_to_node { # So it looks like we will have to switch some stuff around. # local() is useless here as we will be leaving the scope # anyway, and deep cloning is just too fucking expensive - # So replace the first hashref in the node arrayref manually + # So replace the first hashref in the node arrayref manually my @new_from = ($from->[0]); my $sw_idx = { map { (values %$_), 1 } @$switch_branch }; #there's one k/v per join-path @@ -595,15 +785,26 @@ sub _extract_order_criteria { my ($self, $order_by, $sql_maker) = @_; my $parser = sub { - my ($sql_maker, $order_by) = @_; + my ($sql_maker, $order_by, $orig_quote_chars) = @_; return scalar $sql_maker->_order_by_chunks ($order_by) unless wantarray; + my ($lq, $rq, $sep) = map { quotemeta($_) } ( + ($orig_quote_chars ? @$orig_quote_chars : $sql_maker->_quote_chars), + $sql_maker->name_sep + ); + my @chunks; for ($sql_maker->_order_by_chunks ($order_by) ) { - my $chunk = ref $_ ? $_ : [ $_ ]; - $chunk->[0] =~ s/\s+ (?: ASC|DESC ) \s* $//ix; + my $chunk = ref $_ ? [ @$_ ] : [ $_ ]; + ($chunk->[0]) = $sql_maker->_split_order_chunk($chunk->[0]); + + # order criteria may have come back pre-quoted (literals and whatnot) + # this is fragile, but the best we can currently do + $chunk->[0] =~ s/^ $lq (.+?) $rq $sep $lq (.+?) $rq $/"$1.$2"/xe + or $chunk->[0] =~ s/^ $lq (.+) $rq $/$1/x; + push @chunks, $chunk; } @@ -615,9 +816,143 @@ sub _extract_order_criteria { } else { $sql_maker = $self->sql_maker; + + # pass these in to deal with literals coming from + # the user or the deep guts of prefetch + my $orig_quote_chars = [$sql_maker->_quote_chars]; + local $sql_maker->{quote_char}; - return $parser->($sql_maker, $order_by); + return $parser->($sql_maker, $order_by, $orig_quote_chars); + } +} + +sub _order_by_is_stable { + my ($self, $ident, $order_by, $where) = @_; + + my $colinfo = $self->_resolve_column_info($ident, [ + (map { $_->[0] } $self->_extract_order_criteria($order_by)), + $where ? @{$self->_extract_fixed_condition_columns($where)} :(), + ]); + + return undef unless keys %$colinfo; + + my $cols_per_src; + $cols_per_src->{$_->{-source_alias}}{$_->{-colname}} = $_ for values %$colinfo; + + for (values %$cols_per_src) { + my $src = (values %$_)[0]->{-result_source}; + return 1 if $src->_identifying_column_set($_); + } + + return undef; +} + +# this is almost identical to the above, except it accepts only +# a single rsrc, and will succeed only if the first portion of the order +# by is stable. +# returns that portion as a colinfo hashref on success +sub _main_source_order_by_portion_is_stable { + my ($self, $main_rsrc, $order_by, $where) = @_; + + die "Huh... I expect a blessed result_source..." + if ref($main_rsrc) eq 'ARRAY'; + + my @ord_cols = map + { $_->[0] } + ( $self->_extract_order_criteria($order_by) ) + ; + return unless @ord_cols; + + my $colinfos = $self->_resolve_column_info($main_rsrc); + + for (0 .. $#ord_cols) { + if ( + ! $colinfos->{$ord_cols[$_]} + or + $colinfos->{$ord_cols[$_]}{-result_source} != $main_rsrc + ) { + $#ord_cols = $_ - 1; + last; + } + } + + # we just truncated it above + return unless @ord_cols; + + my $order_portion_ci = { map { + $colinfos->{$_}{-colname} => $colinfos->{$_}, + $colinfos->{$_}{-fq_colname} => $colinfos->{$_}, + } @ord_cols }; + + # since all we check here are the start of the order_by belonging to the + # top level $rsrc, a present identifying set will mean that the resultset + # is ordered by its leftmost table in a stable manner + # + # RV of _identifying_column_set contains unqualified names only + my $unqualified_idset = $main_rsrc->_identifying_column_set({ + ( $where ? %{ + $self->_resolve_column_info( + $main_rsrc, $self->_extract_fixed_condition_columns($where) + ) + } : () ), + %$order_portion_ci + }) or return; + + my $ret_info; + my %unqualified_idcols_from_order = map { + $order_portion_ci->{$_} ? ( $_ => $order_portion_ci->{$_} ) : () + } @$unqualified_idset; + + # extra optimization - cut the order_by at the end of the identifying set + # (just in case the user was stupid and overlooked the obvious) + for my $i (0 .. $#ord_cols) { + my $col = $ord_cols[$i]; + my $unqualified_colname = $order_portion_ci->{$col}{-colname}; + $ret_info->{$col} = { %{$order_portion_ci->{$col}}, -idx_in_order_subset => $i }; + delete $unqualified_idcols_from_order{$ret_info->{$col}{-colname}}; + + # we didn't reach the end of the identifying portion yet + return $ret_info unless keys %unqualified_idcols_from_order; + } + + die 'How did we get here...'; +} + +# returns an arrayref of column names which *definitely* have some +# sort of non-nullable equality requested in the given condition +# specification. This is used to figure out if a resultset is +# constrained to a column which is part of a unique constraint, +# which in turn allows us to better predict how ordering will behave +# etc. +# +# this is a rudimentary, incomplete, and error-prone extractor +# however this is OK - it is conservative, and if we can not find +# something that is in fact there - the stack will recover gracefully +# Also - DQ and the mst it rode in on will save us all RSN!!! +sub _extract_fixed_condition_columns { + my ($self, $where, $nested) = @_; + + return unless ref $where eq 'HASH'; + + my @cols; + for my $lhs (keys %$where) { + if ($lhs =~ /^\-and$/i) { + push @cols, ref $where->{$lhs} eq 'ARRAY' + ? ( map { $self->_extract_fixed_condition_columns($_, 1) } @{$where->{$lhs}} ) + : $self->_extract_fixed_condition_columns($where->{$lhs}, 1) + ; + } + elsif ($lhs !~ /^\-/) { + my $val = $where->{$lhs}; + + push @cols, $lhs if (defined $val and ( + ! ref $val + or + (ref $val eq 'HASH' and keys %$val == 1 and defined $val->{'='}) + )); + } } + return $nested ? @cols : \@cols; } 1;