use List::Util 'first';
use Scalar::Util 'blessed';
use Sub::Name 'subname';
+use DBIx::Class::_Util qw(is_plain_value is_literal_value UNRESOLVABLE_CONDITION);
use namespace::clean;
#
# {from} specs, aiding the RDBMS query optimizer
#
sub _prune_unused_joins {
- my $self = shift;
- my ($from, $select, $where, $attrs) = @_;
+ my ($self, $attrs) = @_;
- return $from unless $self->_use_join_optimizer;
+ # only standard {from} specs are supported, and we could be disabled in general
+ return ($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
+ );
- if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY') {
- return $from; # only standard {from} specs are supported
- }
+ my $orig_aliastypes = $self->_resolve_aliastypes_from_select_args($attrs);
- my $aliastypes = $self->_resolve_aliastypes_from_select_args(@_);
+ my $new_aliastypes = { %$orig_aliastypes };
- my $orig_joins = delete $aliastypes->{joining};
- my $orig_multiplying = $aliastypes->{multiplying};
+ # 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};
- my @newfrom = $from->[0]; # FROM head is always present
+ # nuke what will be recalculated
+ delete @{$new_aliastypes}{@reclassify};
- my %need_joins;
+ my @newfrom = $attrs->{from}[0]; # FROM head is always present
- for (values %$aliastypes) {
+ # 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 ( @{$new_aliastypes}{grep { $_ ne 'premultiplied' } keys %$new_aliastypes }) {
# add all requested aliases
$need_joins{$_} = 1 for keys %$_;
$need_joins{$_} = 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 (
(! defined $j->[0]{-alias}) # legacy crap
||
);
}
- 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, $new_aliastypes );
}
#
# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
#
sub _adjust_select_args_for_complex_prefetch {
- my ($self, $from, $select, $where, $attrs) = @_;
+ my ($self, $attrs) = @_;
- $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');
+ $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 @{$outer_attrs}{qw(where bind rows offset group_by _grouped_by_distinct having)};
+ delete @{$outer_attrs}{qw(from bind rows offset group_by _grouped_by_distinct having)};
my $inner_attrs = { %$attrs };
- delete @{$inner_attrs}{qw(from for collapse select as _related_results_construction)};
+ delete @{$inner_attrs}{qw(for collapse select as _related_results_construction)};
# there is no point of ordering the insides if there is no limit
delete $inner_attrs->{order_by} if (
# 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 .. $#$from) {
- my $node = $from->[$i];
+ 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
unless $root_node;
# use the heavy duty resolver to take care of aliased/nonaliased naming
- my $colinfo = $self->_resolve_column_info($from);
+ my $colinfo = $self->_resolve_column_info($inner_attrs->{from});
my $selected_root_columns;
- for my $i (0 .. $#$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 ('.', $root_alias, ($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];
}
# 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)
+ # 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(
- $from,
- [],
- $where,
- $inner_attrs
- );
+ 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;
! $selected_root_columns->{$ci->{-colname}}++
) {
# adding it to both to keep limits not supporting dark selectors happy
- push @$inner_select, $ci->{-fq_colname};
+ push @{$inner_attrs->{select}}, $ci->{-fq_colname};
push @{$inner_attrs->{as}}, $ci->{-fq_colname};
}
}
- # construct the inner $from and lock it in a 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
# 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 $self->{_use_join_optimizer} = 1;
# throw away multijoins since we def. do not care about those inside the subquery
- my ($inner_from, $inner_aliastypes) = $self->_prune_unused_joins ($from, $inner_select, $where, {
+ ($inner_attrs->{from}, my $inner_aliastypes) = $self->_prune_unused_joins ({
%$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 collape 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;
+ 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}++;
}
- 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 colapse
- # 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 => $inner_select,
- });
- }
+ ($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
+ # 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,
);
};
# result by tackling yet another group_by to the outside of the query
# work on a shallow copy
- $from = [ @$from ];
+ my @orig_from = @{$attrs->{from}};
+
- my @outer_from;
+ $outer_attrs->{from} = \ my @outer_from;
# we may not be the head
if ($root_node_offset) {
- # first generate the outer_from, up and including the substitution point
- @outer_from = splice @$from, 0, $root_node_offset;
+ # 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 => $inner_subq,
},
- @{$from->[0]}[1 .. $#{$from->[0]}],
+ # preserve attrs from what is now the head of the from after the splice
+ @{$orig_from[0]}[1 .. $#{$orig_from[0]}],
];
}
else {
};
}
- shift @$from; # what we just replaced above
+ 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_nonselecting_chains) = map { +{
} } 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 (
}
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,
- select => $outer_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;
-
}
- # 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} ||= { -parents => $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 unambiguous unqualified ones)
- my $colinfo = $self->_resolve_column_info ($from);
+ my $colinfo = $self->_resolve_column_info ($attrs->{from});
# set up a botched SQLA
my $sql_maker = $self->sql_maker;
# these are throw away results, do not pollute the bind stack
- local $sql_maker->{select_bind};
local $sql_maker->{where_bind};
local $sql_maker->{group_bind};
local $sql_maker->{having_bind};
# generate sql chunks
my $to_scan = {
restricting => [
- $sql_maker->_recurse_where ($where),
+ $sql_maker->_recurse_where ($attrs->{where}),
$sql_maker->_parse_rs_attrs ({ having => $attrs->{having} }),
],
grouping => [
],
joining => [
$sql_maker->_recurse_from (
- ref $from->[0] eq 'ARRAY' ? $from->[0][0] : $from->[0],
- @{$from}[1 .. $#$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 { ($sql_maker->_recurse_fields($_))[0] } @{$attrs->{select}},
],
ordering => [
map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker),
],
};
- # throw away empty chunks
- $_ = [ map { $_ || () } @$_ ] for values %$to_scan;
+ # throw away empty chunks and all 2-value arrayrefs: the thinking is that these are
+ # bind value specs left in by the sloppy renderer above. It is ok to do this
+ # at this point, since we are going to end up rewriting this crap anyway
+ for my $v (values %$to_scan) {
+ my @nv;
+ for (@$v) {
+ next if (
+ ! defined $_
+ or
+ (
+ ref $_ eq 'ARRAY'
+ and
+ ( @$_ == 0 or @$_ == 2 )
+ )
+ );
+
+ if (ref $_) {
+ require Data::Dumper::Concise;
+ $self->throw_exception("Unexpected ref in scan-plan: " . Data::Dumper::Concise::Dumper($v) );
+ }
+
+ push @nv, $_;
+ }
+
+ $v = \@nv;
+ }
+
+ # kill all selectors which look like a proper subquery
+ # this is a sucky heuristic *BUT* - if we get it wrong the query will simply
+ # fail to run, so we are relatively safe
+ $to_scan->{selecting} = [ grep {
+ $_ !~ / \A \s* \( \s* SELECT \s+ .+? \s+ FROM \s+ .+? \) \s* \z /xsi
+ } @{ $to_scan->{selecting} || [] } ];
# first see if we have any exact matches (qualified or unqualified)
for my $type (keys %$to_scan) {
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})
+ ];
+
+ my ($chunk, $is_desc) = $sql_maker->_split_order_chunk($order_chunks->[$o_idx][0]);
- $chunk = $colinfos->{$chunk}{-fq_colname};
- push @group_by, $chunk unless $group_index{$chunk}++;
+ $new_order_by[$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
- ;
+ $self->throw_exception ( sprintf
+ 'Unable to programatically derive a required group_by from the supplied '
+ . 'order_by criteria. To proceed either add an explicit group_by, or '
+ . 'simplify your order_by to only include plain columns '
+ . '(supplied order_by: %s)',
+ join ', ', map { "'$_'" } @$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 : $attrs->{order_by} ), # same ref as original == unchanged
+ );
}
sub _resolve_ident_sources {
# for all sources
sub _resolve_column_info {
my ($self, $ident, $colnames) = @_;
+
+ return {} if $colnames and ! @$colnames;
+
my $alias2src = $self->_resolve_ident_sources($ident);
my (%seen_cols, @auto_colnames);
sub _inner_join_to_node {
my ($self, $from, $alias) = @_;
- # subqueries and other oddness are naturally not supported
- return $from if (
- ref $from ne 'ARRAY'
- ||
- @$from <= 1
- ||
- ref $from->[0] ne 'HASH'
- ||
- ! $from->[0]{-alias}
- ||
- $from->[0]{-alias} eq $alias # this last bit means $alias is the head of $from - nothing to do
- );
-
- # find the current $alias in the $from structure
- my $switch_branch;
- JOINSCAN:
- for my $j (@{$from}[1 .. $#$from]) {
- if ($j->[0]{-alias} eq $alias) {
- $switch_branch = $j->[0]{-join_path};
- last JOINSCAN;
- }
- }
+ my $switch_branch = $self->_find_join_path_to_node($from, $alias);
- # something else went quite wrong
- return $from unless $switch_branch;
+ return $from unless @{$switch_branch||[]};
# So it looks like we will have to switch some stuff around.
# local() is useless here as we will be leaving the scope
return \@new_from;
}
+sub _find_join_path_to_node {
+ my ($self, $from, $target_alias) = @_;
+
+ # subqueries and other oddness are naturally not supported
+ return undef if (
+ ref $from ne 'ARRAY'
+ ||
+ ref $from->[0] ne 'HASH'
+ ||
+ ! defined $from->[0]{-alias}
+ );
+
+ # no path - the head is the alias
+ return [] if $from->[0]{-alias} eq $target_alias;
+
+ for my $i (1 .. $#$from) {
+ return $from->[$i][0]{-join_path} if ( ($from->[$i][0]{-alias}||'') eq $target_alias );
+ }
+
+ # something else went quite wrong
+ return undef;
+}
+
sub _extract_order_criteria {
my ($self, $order_by, $sql_maker) = @_;
sub _order_by_is_stable {
my ($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)} :(),
- ]);
+ my @cols = (
+ ( map { $_->[0] } $self->_extract_order_criteria($order_by) ),
+ ( $where ? keys %{ $self->_extract_fixed_condition_columns($where) } : () ),
+ ) or return 0;
+
+ my $colinfo = $self->_resolve_column_info($ident, \@cols);
+
+ return keys %$colinfo
+ ? $self->_columns_comprise_identifying_set( $colinfo, \@cols )
+ : 0
+ ;
+}
- return undef unless keys %$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};
return 1 if $src->_identifying_column_set($_);
}
- return undef;
+ return 0;
}
-# this is almost identical to the above, except it accepts only
+# this is almost similar to _order_by_is_stable, except it takes
# 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, $where) = @_;
+sub _extract_colinfo_of_stable_main_source_order_by_portion {
+ my ($self, $attrs) = @_;
+
+ my $nodes = $self->_find_join_path_to_node($attrs->{from}, $attrs->{alias});
- die "Huh... I expect a blessed result_source..."
- if ref($main_rsrc) eq 'ARRAY';
+ return unless defined $nodes;
my @ord_cols = map
{ $_->[0] }
- ( $self->_extract_order_criteria($order_by) )
+ ( $self->_extract_order_criteria($attrs->{order_by}) )
;
return unless @ord_cols;
- my $colinfos = $self->_resolve_column_info($main_rsrc);
+ my $valid_aliases = { map { $_ => 1 } (
+ $attrs->{from}[0]{-alias},
+ map { values %$_ } @$nodes,
+ ) };
- for (0 .. $#ord_cols) {
- if (
- ! $colinfos->{$ord_cols[$_]}
+ my $colinfos = $self->_resolve_column_info($attrs->{from});
+
+ my ($colinfos_to_return, $seen_main_src_cols);
+
+ for my $col (@ord_cols) {
+ # if order criteria is unresolvable - there is nothing we can do
+ my $colinfo = $colinfos->{$col} or last;
+
+ # if we reached the end of the allowed aliases - also nothing we can do
+ last unless $valid_aliases->{$colinfo->{-source_alias}};
+
+ $colinfos_to_return->{$col} = $colinfo;
+
+ $seen_main_src_cols->{$colinfo->{-colname}} = 1
+ if $colinfo->{-source_alias} eq $attrs->{alias};
+ }
+
+ # FIXME the condition may be singling out things on its own, so we
+ # conceivable could come back wi "stable-ordered by nothing"
+ # not confient enough in the parser yet, so punt for the time being
+ return unless $seen_main_src_cols;
+
+ my $main_src_fixed_cols_from_cond = [ $attrs->{where}
+ ? (
+ map
+ {
+ ( $colinfos->{$_} and $colinfos->{$_}{-source_alias} eq $attrs->{alias} )
+ ? $colinfos->{$_}{-colname}
+ : ()
+ }
+ keys %{ $self->_extract_fixed_condition_columns($attrs->{where}) }
+ )
+ : ()
+ ];
+
+ return $attrs->{result_source}->_identifying_column_set([
+ keys %$seen_main_src_cols,
+ @$main_src_fixed_cols_from_cond,
+ ]) ? $colinfos_to_return : ();
+}
+
+# Attempts to flatten a passed in SQLA condition as much as possible towards
+# a plain hashref, *without* altering its semantics. Required by
+# create/populate being able to extract definitive conditions from preexisting
+# resultset {where} stacks
+#
+# FIXME - while relatively robust, this is still imperfect, one of the first
+# things to tackle with DQ
+sub _collapse_cond {
+ my ($self, $where, $where_is_anded_array) = @_;
+
+ if (! $where) {
+ return;
+ }
+ elsif ($where_is_anded_array or ref $where eq 'HASH') {
+
+ my @pairs;
+
+ my @pieces = $where_is_anded_array ? @$where : $where;
+ while (@pieces) {
+ my $chunk = shift @pieces;
+
+ if (ref $chunk eq 'HASH') {
+ push @pairs, map { [ $_ => $chunk->{$_} ] } sort keys %$chunk;
+ }
+ elsif (ref $chunk eq 'ARRAY') {
+ push @pairs, [ -or => $chunk ]
+ if @$chunk;
+ }
+ elsif ( ! ref $chunk) {
+ push @pairs, [ $chunk, shift @pieces ];
+ }
+ else {
+ push @pairs, [ '', $chunk ];
+ }
+ }
+
+ return unless @pairs;
+
+ my @conds = $self->_collapse_cond_unroll_pairs(\@pairs)
+ or return;
+
+ # Consolidate various @conds back into something more compact
+ my $fin;
+
+ for my $c (@conds) {
+ if (ref $c ne 'HASH') {
+ push @{$fin->{-and}}, $c;
+ }
+ else {
+ for my $col (sort keys %$c) {
+ if (exists $fin->{$col}) {
+ my ($l, $r) = ($fin->{$col}, $c->{$col});
+
+ (ref $_ ne 'ARRAY' or !@$_) and $_ = [ -and => $_ ] for ($l, $r);
+
+ if (@$l and @$r and $l->[0] eq $r->[0] and $l->[0] eq '-and') {
+ $fin->{$col} = [ -and => map { @$_[1..$#$_] } ($l, $r) ];
+ }
+ else {
+ $fin->{$col} = [ -and => $fin->{$col}, $c->{$col} ];
+ }
+ }
+ else {
+ $fin->{$col} = $c->{$col};
+ }
+ }
+ }
+ }
+
+ if ( ref $fin->{-and} eq 'ARRAY' and @{$fin->{-and}} == 1 ) {
+ my $piece = (delete $fin->{-and})->[0];
+ if (ref $piece eq 'ARRAY') {
+ $fin->{-or} = $fin->{-or} ? [ $piece, $fin->{-or} ] : $piece;
+ }
+ elsif (! exists $fin->{''}) {
+ $fin->{''} = $piece;
+ }
+ }
+
+ return $fin;
+ }
+ elsif (ref $where eq 'ARRAY') {
+ my @w = @$where;
+
+ while ( @w and (
+ (ref $w[0] eq 'ARRAY' and ! @{$w[0]} )
or
- $colinfos->{$ord_cols[$_]}{-result_source} != $main_rsrc
- ) {
- $#ord_cols = $_ - 1;
- last;
+ (ref $w[0] eq 'HASH' and ! keys %{$w[0]})
+ )) { shift @w };
+
+ return unless @w;
+
+ if ( @w == 1 ) {
+ return ( ref $w[0] )
+ ? $self->_collapse_cond($w[0])
+ : { $w[0] => undef }
+ ;
+ }
+ elsif ( @w == 2 and ! ref $w[0]) {
+ if ( ( $w[0]||'' ) =~ /^\-and$/i ) {
+ return (ref $w[1] eq 'HASH' or ref $w[1] eq 'ARRAY')
+ ? $self->_collapse_cond($w[1], (ref $w[1] eq 'ARRAY') )
+ : $self->throw_exception("Unsupported top-level op/arg pair: [ $w[0] => $w[1] ]")
+ ;
+ }
+ else {
+ return $self->_collapse_cond({ @w });
+ }
}
+ else {
+ return { -or => \@w };
+ }
+ }
+ else {
+ # not a hash not an array
+ return { '' => $where };
}
- # we just truncated it above
- return unless @ord_cols;
+ die 'should not get here';
+}
- my $order_portion_ci = { map {
- $colinfos->{$_}{-colname} => $colinfos->{$_},
- $colinfos->{$_}{-fq_colname} => $colinfos->{$_},
- } @ord_cols };
+sub _collapse_cond_unroll_pairs {
+ my ($self, $pairs) = @_;
- # 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 $ret_info unless keys %unqualified_idcols_from_order;
- }
-
- die 'How did we get here...';
+ my @conds;
+
+ while (@$pairs) {
+ my ($lhs, $rhs) = @{ shift @$pairs };
+
+ if ($lhs eq '') {
+ push @conds, $self->_collapse_cond($rhs);
+ }
+ elsif ( $lhs =~ /^\-and$/i ) {
+ push @conds, $self->_collapse_cond($rhs, (ref $rhs eq 'ARRAY'));
+ }
+ elsif ( $lhs =~ /^\-or$/i ) {
+ push @conds, $self->_collapse_cond(
+ (ref $rhs eq 'HASH') ? [ map { $_ => $rhs->{$_} } sort keys %$rhs ] : $rhs
+ );
+ }
+ else {
+ if (ref $rhs eq 'HASH' and ! keys %$rhs) {
+ # FIXME - SQLA seems to be doing... nothing...?
+ }
+ elsif (ref $rhs eq 'HASH' and keys %$rhs == 1 and exists $rhs->{'='}) {
+ for my $p ($self->_collapse_cond_unroll_pairs([ [ $lhs => $rhs->{'='} ] ])) {
+
+ # extra sanity check
+ if (keys %$p > 1) {
+ require Data::Dumper::Concise;
+ local $Data::Dumper::Deepcopy = 1;
+ $self->throw_exception(
+ "Internal error: unexpected collapse unroll:"
+ . Data::Dumper::Concise::Dumper { in => { $lhs => $rhs }, out => $p }
+ );
+ }
+
+ my ($l, $r) = %$p;
+
+ push @conds, ( ! length ref $r or is_plain_value($r) )
+ ? { $l => $r }
+ : { $l => { '=' => $r } }
+ ;
+ }
+ }
+ elsif (ref $rhs eq 'ARRAY') {
+ # some of these conditionals encounter multi-values - roll them out using
+ # an unshift, which will cause extra looping in the while{} above
+ if (! @$rhs ) {
+ push @conds, { $lhs => [] };
+ }
+ elsif ( ($rhs->[0]||'') =~ /^\-(?:and|or)$/i ) {
+ $self->throw_exception("Value modifier not followed by any values: $lhs => [ $rhs->[0] ] ")
+ if @$rhs == 1;
+
+ if( $rhs->[0] =~ /^\-and$/i ) {
+ unshift @$pairs, map { [ $lhs => $_ ] } @{$rhs}[1..$#$rhs];
+ }
+ # if not an AND then it's an OR
+ elsif(@$rhs == 2) {
+ unshift @$pairs, [ $lhs => $rhs->[1] ];
+ }
+ else {
+ push @conds, { $lhs => $rhs };
+ }
+ }
+ elsif (@$rhs == 1) {
+ unshift @$pairs, [ $lhs => $rhs->[0] ];
+ }
+ else {
+ push @conds, { $lhs => $rhs };
+ }
+ }
+ else {
+ push @conds, { $lhs => $rhs };
+ }
+ }
+ }
+
+ return @conds;
}
-# 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.
+# Analyzes a given condition and attempts to extract all columns
+# with a definitive fixed-condition criteria. Returns a hashref
+# of k/v pairs suitable to be passed to set_columns(), with a
+# MAJOR CAVEAT - multi-value (contradictory) equalities are still
+# represented as a reference to the UNRESOVABLE_CONDITION constant
+# The reason we do this is that some codepaths only care about the
+# codition being stable, as opposed to actually making sense
+#
+# The normal mode 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!!!
+# With the optional "consider_nulls" boolean argument, the function
+# is instead used to infer inambiguous values from conditions
+# (e.g. the inheritance of resultset conditions on new_result)
+#
+my $undef_marker = \ do{ my $x = 'undef' };
sub _extract_fixed_condition_columns {
- my ($self, $where, $nested) = @_;
+ my ($self, $where, $consider_nulls) = @_;
+ my $where_hash = $self->_collapse_cond($_[1]);
- return unless ref $where eq 'HASH';
+ my $res = {};
+ my ($c, $v);
+ for $c (keys %$where_hash) {
+ my $vals;
- 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->{$lhs}, 1)
- ;
+ if (!defined ($v = $where_hash->{$c}) ) {
+ $vals->{$undef_marker} = $v if $consider_nulls
+ }
+ elsif (
+ ! length ref $v
+ or
+ is_plain_value ($v)
+ ) {
+ $vals->{$v} = $v;
+ }
+ elsif (
+ ref $v eq 'HASH'
+ and
+ keys %$v == 1
+ and
+ ref $v->{'='}
+ and
+ # do not need to check for plain values - _collapse_cond did it for us
+ is_literal_value($v->{'='})
+ ) {
+ $vals->{$v->{'='}} = $v->{'='};
+ }
+ elsif (ref $v eq 'ARRAY' and ($v->[0]||'') eq '-and') {
+ for ( @{$v}[1..$#$v] ) {
+ my $subval = $self->_extract_fixed_condition_columns({ $c => $_ }, 'consider nulls'); # always fish nulls out on recursion
+ next unless exists $subval->{$c}; # didn't find anything
+ $vals->{defined $subval->{$c} ? $subval->{$c} : $undef_marker} = $subval->{$c};
+ }
}
- 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 $val->{'='})
- ));
+ if (keys %$vals == 1) {
+ ($res->{$c}) = (values %$vals)
+ unless !$consider_nulls and exists $vals->{$undef_marker};
+ }
+ elsif (keys %$vals > 1) {
+ $res->{$c} = UNRESOLVABLE_CONDITION;
}
}
- return $nested ? @cols : \@cols;
+
+ $res;
}
1;