# {from} specs, aiding the RDBMS query optimizer
#
sub _prune_unused_joins {
- my ($self) = shift;
-
+ my $self = shift;
my ($from, $select, $where, $attrs) = @_;
+ return $from unless $self->_use_join_optimizer;
+
if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY') {
return $from; # only standard {from} specs are supported
}
push @{$inner_attrs->{as}}, $attrs->{as}[$i];
}
- # construct the inner $from for the subquery
+ # 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)
- my $inner_from = $self->_prune_unused_joins ($from, $inner_select, $where, {
- group_by => ['dummy'], %$inner_attrs,
- });
-
- # if a multi-type join was needed in the subquery - add a group_by to simulate the
- # collapse in the subq
- $inner_attrs->{group_by} ||= $inner_select
- if first { ! $_->[0]{-is_single} } (@{$inner_from}[1 .. $#$inner_from]);
-
- # generate the subquery
- my $subq = $self->_select_args_to_query (
- $inner_from,
- $inner_select,
- $where,
- $inner_attrs,
- );
- my $subq_joinspec = {
- -alias => $attrs->{alias},
- -source_handle => $inner_from->[0]{-source_handle},
- $attrs->{alias} => $subq,
+ my $subq_joinspec = 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,
+ });
+
+ my $inner_aliastypes =
+ $self->_resolve_aliastypes_from_select_args( $inner_from, $inner_select, $where, $inner_attrs );
+
+ # if a multi-type non-selecting (only restricting) join was needed in the subquery
+ # add a group_by to simulate the collapse in the subq
+ if (
+ ! $inner_attrs->{group_by}
+ and
+ first {
+ $inner_aliastypes->{restricting}{$_}
+ and
+ ! $inner_aliastypes->{selecting}{$_}
+ } ( 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;
+ }
+
+ # we already optimized $inner_from above
+ local $self->{_use_join_optimizer} = 0;
+
+ # generate the subquery
+ my $subq = $self->_select_args_to_query (
+ $inner_from,
+ $inner_select,
+ $where,
+ $inner_attrs,
+ );
+
+ +{
+ -alias => $attrs->{alias},
+ -source_handle => $inner_from->[0]{-source_handle},
+ $attrs->{alias} => $subq,
+ };
};
# Generate the outer from - this is relatively easy (really just replace
}
}
- # scan the from spec against different attributes, and see which joins are needed
+ # scan the *remaining* from spec against different attributes, and see which joins are needed
# in what role
my $outer_aliastypes =
$self->_resolve_aliastypes_from_select_args( $from, $outer_select, $where, $outer_attrs );
# set up a botched SQLA
my $sql_maker = $self->sql_maker;
- local $sql_maker->{having_bind}; # these are throw away results
+ # these are throw away results, do not pollute the bind stack
+ local $sql_maker->{having_bind};
+ local $sql_maker->{select_bind};
# we can't scan properly without any quoting (\b doesn't cut it
# everywhere), so unless there is proper quoting set - use our
local $sql_maker->{name_sep} = $sql_maker->{name_sep};
unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
- $sql_maker->{quote_char} = "\x00";
+ $sql_maker->{quote_char} = ["\x00", "\xFF"];
+ # if we don't unset it we screw up retarded but unfortunately working
+ # 'MAX(foo.bar)' => { '>', 3 }
$sql_maker->{name_sep} = '';
}
}),
],
selecting => [
- $self->_extract_order_columns ($attrs->{order_by}, $sql_maker),
$sql_maker->_recurse_fields ($select),
+ ( map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker) ),
],
};
);
}
- # mark all join parents as mentioned
+ # mark all restricting/selecting join parents as such
# (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too )
- for my $type (keys %$aliases_by_type) {
- for my $alias (keys %{$aliases_by_type->{$type}}) {
+ for my $type (qw/restricting selecting/) {
+ for my $alias (keys %{$aliases_by_type->{$type}||{}}) {
$aliases_by_type->{$type}{$_} = 1
for (map { values %$_ } @{ $alias_list->{$alias}{-join_path} || [] });
}
return $aliases_by_type;
}
+# This is the engine behind { distinct => 1 }
+sub _group_over_selection {
+ my ($self, $from, $select, $order_by) = @_;
+
+ my $rs_column_list = $self->_resolve_column_info ($from);
+
+ my (@group_by, %group_index);
+
+ for (@$select) {
+ if (! ref($_) or ref ($_) ne 'HASH' ) {
+ push @group_by, $_;
+ $group_index{$_}++;
+ if ($rs_column_list->{$_} and $_ !~ /\./ ) {
+ # add a fully qualified version as well
+ $group_index{"$rs_column_list->{$_}{-source_alias}.$_"}++;
+ }
+ }
+ }
+
+ # add any order_by parts 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)) {
+ # 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 {
+ push @leftovers, $_;
+ next;
+ };
+
+ $chunk = "$colinfo->{-source_alias}.$chunk" if $chunk !~ /\./;
+ push @group_by, $chunk unless $group_index{$chunk}++;
+ }
+
+ return wantarray
+ ? (\@group_by, (@leftovers ? \@leftovers : undef) )
+ : \@group_by
+ ;
+}
+
sub _resolve_ident_sources {
my ($self, $ident) = @_;
my ($self, $ident, $colnames) = @_;
my ($alias2src, $root_alias) = $self->_resolve_ident_sources($ident);
- my (%return, %seen_cols, @auto_colnames);
+ my (%seen_cols, @auto_colnames);
# compile a global list of column names, to be able to properly
# disambiguate unqualified column names (if at all possible)
grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols),
];
- COLUMN:
+ my (%return, $colinfos);
foreach my $col (@$colnames) {
- my ($alias, $colname) = $col =~ m/^ (?: ([^\.]+) \. )? (.+) $/x;
+ my ($source_alias, $colname) = $col =~ m/^ (?: ([^\.]+) \. )? (.+) $/x;
- unless ($alias) {
- # see if the column was seen exactly once (so we know which rsrc it came from)
- if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1) {
- $alias = $seen_cols{$colname}[0];
- }
- else {
- next COLUMN;
- }
- }
+ # if the column was seen exactly once - we know which rsrc it came from
+ $source_alias ||= $seen_cols{$colname}[0]
+ if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1);
- my $rsrc = $alias2src->{$alias};
- $return{$col} = $rsrc && {
- %{$rsrc->column_info($colname)},
+ next unless $source_alias;
+
+ my $rsrc = $alias2src->{$source_alias}
+ or next;
+
+ $return{$col} = {
+ %{ ( $colinfos->{$source_alias} ||= $rsrc->columns_info )->{$colname} },
-result_source => $rsrc,
- -source_alias => $alias,
+ -source_alias => $source_alias,
};
}
return $cond;
}
-sub _extract_order_columns {
+sub _extract_order_criteria {
my ($self, $order_by, $sql_maker) = @_;
my $parser = sub {
unless wantarray;
my @chunks;
- for my $chunk (map { ref $_ ? @$_ : $_ } ($sql_maker->_order_by_chunks ($order_by) ) ) {
- $chunk =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
+ for ($sql_maker->_order_by_chunks ($order_by) ) {
+ my $chunk = ref $_ ? $_ : [ $_ ];
+ $chunk->[0] =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
push @chunks, $chunk;
}
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