$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 %$_;
);
}
- 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 );
}
#
# 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 $self->{_use_join_optimizer} = 1;
# throw away multijoins since we def. do not care about those inside the subquery
%$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
} } 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};
}
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
# the outer select to exclude joins you didn't want in the first place
#
# OTOH it can be seen as a plus: <ash> (notes that this query would make a DBA cry ;)
-
return $outer_attrs;
}
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}}) {
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)
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, $attrs) = @_;
}
}
- # add any order_by parts *from the main source* that are not already
- # present in the group_by
- # we need to be careful not to add any named functions/aggregates
- # i.e. order_by => [ ... { count => 'foo' } ... ]
- my @leftovers;
- for ($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 : $attrs->{order_by} ), # same ref as original == unchanged
+ );
}
sub _resolve_ident_sources {
sub _order_by_is_stable {
my ($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};
projects / dbsrgits/DBIx-Class.git / blobdiff