# {from} specs, aiding the RDBMS query optimizer
#
sub _prune_unused_joins {
- my $self = shift;
- my ($from, $select, $where, $attrs) = @_;
+ my ($self, $attrs) = @_;
+
+ # only standard {from} specs are supported, and we could be disabled in general
+ return ($attrs->{from}, {}) unless (
+ ref $attrs->{from} eq 'ARRAY'
+ and
+ @{$attrs->{from}} > 1
+ and
+ ref $attrs->{from}[0] eq 'HASH'
+ and
+ ref $attrs->{from}[1] eq 'ARRAY'
+ and
+ $self->_use_join_optimizer
+ );
- return $from unless $self->_use_join_optimizer;
+ my $orig_aliastypes = $self->_resolve_aliastypes_from_select_args($attrs);
- if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY') {
- return $from; # only standard {from} specs are supported
- }
+ my $new_aliastypes = { %$orig_aliastypes };
- my $aliastypes = $self->_resolve_aliastypes_from_select_args(@_);
+ # 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} if $attrs->{group_by};
+ # 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 = $from->[0]; # FROM head is always present
+ 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 %$_;
# 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]) {
+
+ for my $j (@{$attrs->{from}}[1..$#{$attrs->{from}}]) {
push @newfrom, $j if (
- (! $j->[0]{-alias}) # legacy crap
+ (! defined $j->[0]{-alias}) # legacy crap
||
$need_joins{$j->[0]{-alias}}
);
}
- return \@newfrom;
+ # 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, $new_aliastypes );
}
#
# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
#
sub _adjust_select_args_for_complex_prefetch {
- my ($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 $from->[1] ne 'ARRAY');
+ my ($self, $attrs) = @_;
+
+ $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute') unless (
+ ref $attrs->{from} eq 'ARRAY'
+ and
+ @{$attrs->{from}} > 1
+ and
+ ref $attrs->{from}[0] eq 'HASH'
+ and
+ ref $attrs->{from}[1] eq '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/;
-
- my $inner_attrs = { %$attrs, _is_internal_subuery => 1 };
- delete $inner_attrs->{$_} for qw/for collapse _prefetch_selector_range _collapse_order_by select as/;
+ delete @{$outer_attrs}{qw(from bind rows offset group_by _grouped_by_distinct having)};
+ my $inner_attrs = { %$attrs };
+ delete @{$inner_attrs}{qw(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 = [];
+ $outer_attrs->{select} = [ @{$attrs->{select}} ];
+
+ my ($root_node, $root_node_offset);
+
+ for my $i (0 .. $#{$inner_attrs->{from}}) {
+ my $node = $inner_attrs->{from}[$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;
+
+ # use the heavy duty resolver to take care of aliased/nonaliased naming
+ my $colinfo = $self->_resolve_column_info($inner_attrs->{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];
+ for my $i (0 .. $#{$outer_attrs->{select}}) {
+ my $sel = $outer_attrs->{select}->[$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") );
+ $outer_attrs->{select}->[$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, $sel;
+ push @{$inner_attrs->{select}}, $sel;
push @{$inner_attrs->{as}}, $attrs->{as}[$i];
}
- # 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)
+ # 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), or wheres. In other words everything but the inner
+ # selector
+ # We can not just fetch everything because a potential has_many restricting
+ # join collapse *will not work* on heavy data types.
+ my $connecting_aliastypes = $self->_resolve_aliastypes_from_select_args({
+ %$inner_attrs,
+ select => [],
+ });
+
+ 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_attrs->{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
+ # throw away all non-selecting, non-restricting multijoins
+ # (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;
- 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
+ ($inner_attrs->{from}, my $inner_aliastypes) = $self->_prune_unused_joins ({
+ %$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 for limits
+ # we will need to add a group_by to collapse the resultset for proper counts
if (
- ! $inner_attrs->{group_by}
+ grep { $_ ne $root_alias } keys %{ $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} )
) {
- 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;
+
+ my $cur_sel = { map { $_ => 1 } @{$inner_attrs->{select}} };
+
+ # *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,
+ );
+ for my $col (@pks) {
+ push @{ $inner_select_with_extras ||= [ @{$inner_attrs->{select}} ] }, $col
+ unless $cur_sel->{$col}++;
+ }
+
+ ($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_from above
- local $self->{_use_join_optimizer} = 0;
+ # we already optimized $inner_attrs->{from} above
+ # and already local()ized
+ $self->{_use_join_optimizer} = 0;
# generate the subquery
$self->_select_args_to_query (
- $inner_from,
- $inner_select,
- $where,
+ @{$inner_attrs}{qw(from select where)},
$inner_attrs,
);
};
# - 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
- $from = [ @$from ];
+ # work on a shallow copy
+ my @orig_from = @{$attrs->{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
+ $outer_attrs->{from} = \ my @outer_from;
- 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, $j;
- }
+ # we may not be the head
+ if ($root_node_offset) {
+ # first generate the outer_from, up to the substitution point
+ @outer_from = splice @orig_from, 0, $root_node_offset;
+
+ # substitute the subq at the right spot
+ push @outer_from, [
+ {
+ -alias => $root_alias,
+ -rsrc => $root_node->{-rsrc},
+ $root_alias => $inner_subq,
+ },
+ # preserve attrs from what is now the head of the from after the splice
+ @{$orig_from[0]}[1 .. $#{$orig_from[0]}],
+ ];
+ }
+ else {
+ @outer_from = {
+ -alias => $root_alias,
+ -rsrc => $root_node->{-rsrc},
+ $root_alias => $inner_subq,
+ };
}
+ shift @orig_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 =
- $self->_resolve_aliastypes_from_select_args( $from, $outer_select, $where, $outer_attrs );
+ my $outer_aliastypes = $outer_attrs->{_aliastypes} =
+ $self->_resolve_aliastypes_from_select_args({ %$outer_attrs, from => \@orig_from });
# 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,
- # to guard against cross-join explosions
- my $need_outer_group_by;
- while (my $j = shift @$from) {
+ my $may_need_outer_group_by;
+ while (my $j = shift @orig_from) {
my $alias = $j->[0]{-alias};
if (
) {
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;
+ $may_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}) {
-
- my $unprocessed_order_chunks;
- ($outer_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection (
- \@outer_from, $outer_select, $outer_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;
-
+ # 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,
+ });
}
- # This is totally horrific - the $where ends up in both the inner and outer query
+ # This is totally horrific - the {where} ends up in both the inner and outer query
# 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: <ash> (notes that this query would make a DBA cry ;)
- return (\@outer_from, $outer_select, $where, $outer_attrs);
+ return $outer_attrs;
}
#
#
# 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
# happen is for it to fail due to some scalar SQL, which in turn will
# result in a vocal exception.
sub _resolve_aliastypes_from_select_args {
- my ( $self, $from, $select, $where, $attrs ) = @_;
+ my ( $self, $attrs ) = @_;
$self->throw_exception ('Unable to analyze custom {from}')
- if ref $from ne 'ARRAY';
+ if ref $attrs->{from} ne 'ARRAY';
# what we will return
my $aliases_by_type;
# see what aliases are there to work with
+ # and record who is a multiplier and who is premultiplied
my $alias_list;
- for (@$from) {
- my $j = $_;
+ for my $node (@{$attrs->{from}}) {
+
+ my $j = $node;
$j = $j->[0] if ref $j eq 'ARRAY';
my $al = $j->{-alias}
or next;
$alias_list->{$al} = $j;
- $aliases_by_type->{multiplying}{$al} ||= $j->{-join_path}||[] if (
+
+ $aliases_by_type->{multiplying}{$al} ||= { -parents => $j->{-join_path}||[] }
# not array == {from} head == can't be multiplying
- ( ref($_) 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 unqualified ones)
- my $colinfo = $self->_resolve_column_info ($from);
+ # get a column to source/alias map (including unambiguous unqualified ones)
+ my $colinfo = $self->_resolve_column_info ($attrs->{from});
# set up a botched SQLA
my $sql_maker = $self->sql_maker;
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
# generate sql chunks
my $to_scan = {
restricting => [
- $sql_maker->_recurse_where ($where),
- $sql_maker->_parse_rs_attrs ({
- map { $_ => $attrs->{$_} } (qw/group_by having/)
- }),
+ $sql_maker->_recurse_where ($attrs->{where}),
+ $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 $attrs->{from}[0] eq 'ARRAY' ? $attrs->{from}[0][0] : $attrs->{from}[0],
+ @{$attrs->{from}}[1 .. $#{$attrs->{from}}],
+ ),
],
selecting => [
- $sql_maker->_recurse_fields ($select),
- ( map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker) ),
+ $sql_maker->_recurse_fields ($attrs->{select}),
+ ],
+ 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;
+ }
}
}
}
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;
}
}
}
# 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 $aliases_by_type;
}
-# This is the engine behind { distinct => 1 }
+# This is the engine behind { distinct => 1 } and the general
+# complex prefetch grouper
sub _group_over_selection {
- my ($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->{$_}{-source_alias}.$_"}++;
}
}
}
+ my @order_by = $self->_extract_order_criteria($attrs->{order_by})
+ or return (\@group_by, $attrs->{order_by});
+
# add any order_by parts that are not already present in the group_by
- # we need to be careful not to add any named functions/aggregates
- # i.e. order_by => [ ... { count => 'foo' } ... ]
- my @leftovers;
- for ($self->_extract_order_criteria($order_by)) {
+ # to maintain SQL cross-compatibility and general sanity
+ #
+ # also in case the original selection is *not* unique, or in case part
+ # of the ORDER BY refers to a multiplier - we will need to replace the
+ # skipped order_by elements with their MIN/MAX equivalents as to maintain
+ # the proper overall order without polluting the group criteria (and
+ # possibly changing the outcome entirely)
+
+ my ($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];
- 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}++;
+ next unless $chunk_ci;
+
+ # no duplication of group criteria
+ next if $group_index{$chunk_ci->{-fq_colname}};
+
+ $aliastypes ||= (
+ $attrs->{_aliastypes}
+ or
+ $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 @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})
+ ];
+
+ 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 : $attrs->{order_by} ), # same ref as original == unchanged
+ );
}
sub _resolve_ident_sources {
my ($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') {
my $tabinfo;
if (ref $_ eq 'HASH') {
$tabinfo = $_;
- $rs_alias = $tabinfo->{-alias};
}
if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') {
$tabinfo = $_->[0];
}
}
- return ($alias2source, $rs_alias);
+ return $alias2source;
}
# Takes $ident, \@column_names
# for all sources
sub _resolve_column_info {
my ($self, $ident, $colnames) = @_;
- my ($alias2src, $root_alias) = $self->_resolve_ident_sources($ident);
+ my $alias2src = $self->_resolve_ident_sources($ident);
my (%seen_cols, @auto_colnames);
return \@new_from;
}
-# yet another atrocity: attempt to extract all columns from a
-# where condition by hooking _quote
-sub _extract_condition_columns {
- my ($self, $cond, $sql_maker) = @_;
-
- return [] unless $cond;
-
- $sql_maker ||= $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_";
-
- unless ($smic_class->isa('SQL::Abstract')) {
-
- no strict 'refs';
- *{"${smic_class}::_quote"} = subname "${smic_class}::_quote" => sub {
- my ($self, $ident) = @_;
- if (ref $ident eq 'SCALAR') {
- $ident = $$ident;
- my $storage_quotes = $self->sql_quote_char || '"';
- my ($ql, $qr) = map
- { quotemeta $_ }
- (ref $storage_quotes eq 'ARRAY' ? @$storage_quotes : ($storage_quotes) x 2 )
- ;
-
- while ($ident =~ /
- $ql (\w+) $qr
- |
- ([\w\.]+)
- /xg) {
- $self->{_captured_idents}{$1||$2}++;
- }
- }
- else {
- $self->{_captured_idents}{$ident}++;
- }
- return $ident;
- };
-
- *{"${smic_class}::_get_captured_idents"} = subname "${smic_class}::_get_captures" => sub {
- (delete shift->{_captured_idents}) || {};
- };
-
- $self->inject_base ($smic_class, $orig_sm_class);
-
- }
-
- $smic_class->new();
- };
-
- $sql_maker->_recurse_where($cond);
-
- return [ sort keys %{$sql_maker->_get_captured_idents} ];
-}
-
sub _extract_order_criteria {
my ($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;
}
}
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, [
+ my @cols = (
(map { $_->[0] } $self->_extract_order_criteria($order_by)),
$where ? @{$self->_extract_fixed_condition_columns($where)} :(),
- ]);
+ ) or return undef;
- return undef unless keys %$colinfo;
+ my $colinfo = $self->_resolve_column_info($ident, \@cols);
+
+ return keys %$colinfo
+ ? $self->_columns_comprise_identifying_set( $colinfo, \@cols )
+ : undef
+ ;
+}
+
+sub _columns_comprise_identifying_set {
+ my ($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};
return undef;
}
-# returns an arrayref of column names which *definitely* have som
+# 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 $ret_info unless keys %unqualified_idcols_from_order;
+ }
+
+ die 'How did we get here...';
+}
+
+# returns an arrayref of column names which *definitely* have some
# sort of non-nullable equality requested in the given condition
# specification. This is used to figure out if a resultset is
# constrained to a column which is part of a unique constraint,
# something that is in fact there - the stack will recover gracefully
# Also - DQ and the mst it rode in on will save us all RSN!!!
sub _extract_fixed_condition_columns {
- my ($self, $where, $nested) = @_;
+ my ($self, $where) = @_;
return unless ref $where eq 'HASH';
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)
+ ? ( map { @{ $self->_extract_fixed_condition_columns($_) } } @{$where->{$lhs}} )
+ : @{ $self->_extract_fixed_condition_columns($where->{$lhs}) }
;
}
elsif ($lhs !~ /^\-/) {
));
}
}
- return $nested ? @cols : \@cols;
+ return \@cols;
}
1;