my ($self, $from, $select, $where, $attrs) = @_;
$self->throw_exception ('Nothing to prefetch... how did we get here?!')
- if not @{$attrs->{_prefetch_selector_range}};
+ 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');
-
# 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/;
- my $inner_attrs = { %$attrs, _is_internal_subuery => 1 };
- delete $inner_attrs->{$_} for qw/for collapse _prefetch_selector_range _collapse_order_by select as/;
+ my $inner_attrs = { %$attrs };
+ delete $inner_attrs->{$_} for qw/for collapse _prefetch_selector_range select as/;
-
- # 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]
- ];
- }
+ # if the user did not request it, there is no point using it inside
+ delete $inner_attrs->{order_by} if delete $inner_attrs->{_order_is_artificial};
# generate the inner/outer select lists
# for inside we consider only stuff *not* brought in by the prefetch
my $outer_select = [ @$select ];
my $inner_select = [];
+ my ($root_source, $root_source_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 $attrs->{alias} and $root_source = $h->{-rsrc} ) {
+ $root_source_offset = $i;
+ last;
+ }
+ }
+
+ $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
+ unless $root_source;
+
+ # use the heavy duty resolver to take care of aliased/nonaliased naming
+ my $colinfo = $self->_resolve_column_info($from);
+ my $selected_root_columns;
+
my ($p_start, $p_end) = @{$outer_attrs->{_prefetch_selector_range}};
for my $i (0 .. $p_start - 1, $p_end + 1 .. $#$outer_select) {
my $sel = $outer_select->[$i];
$sel->{-as} ||= $attrs->{as}[$i];
$outer_select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "inner_column_$i") );
}
+ elsif (! ref $sel and my $ci = $colinfo->{$sel}) {
+ $selected_root_columns->{$ci->{-colname}} = 1;
+ }
push @$inner_select, $sel;
push @{$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. We can not just fetch everything because a potential
+ # has_many restricting join collapse *will not work* on heavy data types.
+ # Time for more horrible SQL parsing, aughhhh
+
+ # MASSIVE FIXME - in fact when we are fully transitioned to DQ and the support is
+ # is sane - we will need to trim the select list to *only* fetch stuff that is
+ # necessary to build joins. In the current implementation if I am selecting a blob
+ # and the group_by kicks in - we are fucked, and all the user can do is not select
+ # that column. This is silly!
+
+ my $retardo_sqla_cache = {};
+ for my $cond ( map { $_->[1] } @{$from}[$root_source_offset + 1 .. $#$from] ) {
+ for my $col (@{$self->_extract_condition_columns($cond, $retardo_sqla_cache)}) {
+ my $ci = $colinfo->{$col};
+ if (
+ $ci
+ and
+ $ci->{-source_alias} eq $attrs->{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
# - 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_source_offset) {
+ # first generate the outer_from, up to the substitution point
+ @outer_from = splice @$from, 0, $root_source_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;
- }
+ my $root_node = shift @$from;
+
+ push @outer_from, [
+ {
+ -alias => $attrs->{alias},
+ -rsrc => $root_node->[0]{-rsrc},
+ $attrs->{alias} => $inner_subq,
+ },
+ @{$root_node}[1 .. $#$root_node],
+ ];
+ }
+ else {
+ my $root_node = shift @$from;
+
+ @outer_from = {
+ -alias => $attrs->{alias},
+ -rsrc => $root_node->{-rsrc},
+ $attrs->{alias} => $inner_subq,
+ };
}
# scan the *remaining* from spec against different attributes, and see which joins are needed
}
}
- # demote the outer_from head
- $outer_from[0] = $outer_from[0][0];
-
if ($need_outer_group_by and ! $outer_attrs->{group_by}) {
my $unprocessed_order_chunks;
# yet another atrocity: attempt to extract all columns from a
# where condition by hooking _quote
sub _extract_condition_columns {
- my ($self, $cond, $sql_maker) = @_;
+ my ($self, $cond, $sql_maker_cache) = @_;
return [] unless $cond;
- $sql_maker ||= $self->{_sql_ident_capturer} ||= do {
+ my $sm = $sql_maker_cache->{condparser} ||= $self->{_sql_ident_capturer} ||= do {
# FIXME - replace with a Moo trait
my $orig_sm_class = ref $self->sql_maker;
my $smic_class = "${orig_sm_class}::_IdentCapture_";
$smic_class->new();
};
- $sql_maker->_recurse_where($cond);
+ $sm->_recurse_where($cond);
- return [ sort keys %{$sql_maker->_get_captured_idents} ];
+ return [ sort keys %{$sm->_get_captured_idents} ];
}
sub _extract_order_criteria {
}
sub _order_by_is_stable {
- my ($self, $ident, $order_by) = @_;
+ my ($self, $ident, $order_by, $where) = @_;
- my $colinfo = $self->_resolve_column_info(
- $ident, [ map { $_->[0] } $self->_extract_order_criteria($order_by) ]
- );
+ 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;
return undef;
}
+# returns an arrayref of column names which *definitely* have som
+# 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;
projects / dbsrgits/DBIx-Class.git / blobdiff