[Bast-commits] r8318 -
DBIx-Class/0.08/branches/prefetch_pager/lib/DBIx/Class/Storage
ribasushi at dev.catalyst.perl.org
ribasushi at dev.catalyst.perl.org
Fri Jan 15 02:02:21 GMT 2010
Author: ribasushi
Date: 2010-01-15 02:02:21 +0000 (Fri, 15 Jan 2010)
New Revision: 8318
Modified:
DBIx-Class/0.08/branches/prefetch_pager/lib/DBIx/Class/Storage/DBIHacks.pm
Log:
Better refactor
Modified: DBIx-Class/0.08/branches/prefetch_pager/lib/DBIx/Class/Storage/DBIHacks.pm
===================================================================
--- DBIx-Class/0.08/branches/prefetch_pager/lib/DBIx/Class/Storage/DBIHacks.pm 2010-01-15 00:38:53 UTC (rev 8317)
+++ DBIx-Class/0.08/branches/prefetch_pager/lib/DBIx/Class/Storage/DBIHacks.pm 2010-01-15 02:02:21 UTC (rev 8318)
@@ -63,28 +63,30 @@
push @$inner_select, $sel;
}
+
+ # scan the from spec against different attributes, and see which joins are needed
+ # in what role
+ my $inner_aliaslist =
+ $self->_resolve_aliases_from_select_args( $from, $where, $inner_select, $inner_attrs );
+ my $outer_aliaslist =
+ $self->_resolve_aliases_from_select_args( $from, $where, $outer_select, $outer_attrs );
+
+
+
# normalize a copy of $from, so it will be easier to work with further
# down (i.e. promote the initial hashref to an AoH)
$from = [ @$from ];
$from->[0] = [ $from->[0] ];
- my ( $ra1, $sa1, $pa1 ) =
- $self->_resolve_aliases_from_select_args( $from, $where, $inner_select,
- $inner_attrs, );
- my ( $ra2, $sa2, $pa2 ) =
- $self->_resolve_aliases_from_select_args( $from, $where, $outer_select,
- $outer_attrs, );
- my $restrict_aliases = { %$ra1, %$ra2 };
- my $select_aliases = { %$sa1, %$sa2 };
- my $prefetch_aliases = { %$pa1, %$pa2 };
# construct the inner $from for the subquery
- my %inner_joins = (map { %{$_ || {}} } ($restrict_aliases, $select_aliases) );
+ my %inner_joins = (map { %{$inner_aliaslist->{$_} || {}} } (qw/restrict select/) );
my @inner_from;
for my $j (@$from) {
push @inner_from, $j if $inner_joins{$j->[0]{-alias}};
}
+
# if a multi-type join was needed in the subquery ("multi" is indicated by
# presence in {collapse}) - add a group_by to simulate the collapse in the subq
unless ($inner_attrs->{group_by}) {
@@ -148,10 +150,10 @@
while (my $j = shift @$from) {
my $alias = $j->[0]{-alias};
- if ($select_aliases->{$alias} || $prefetch_aliases->{$alias}) {
+ if ($outer_aliaslist->{select}{$alias}) {
push @outer_from, $j;
}
- elsif ($restrict_aliases->{$alias}) {
+ elsif ($outer_aliaslist->{restrict}{$alias}) {
push @outer_from, $j;
# FIXME - this should be obviated by SQLA2, as I'll be able to
@@ -185,148 +187,65 @@
return (\@outer_from, $outer_select, $where, $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
+# 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 an unqualified column, which in
+# turn will result in a vocal exception. Qualifying the column will
+# invariably solve the problem.
sub _resolve_aliases_from_select_args {
my ( $self, $from, $where, $select, $attrs ) = @_;
- my %original_join_info = map { $_->[0]{-alias} => $_->[0] } (@$from);
- # decide which parts of the join will remain in either part of
- # the outer/inner query
+ $self->throw_exception ('Unable to analyze custom {from}')
+ if ref $from ne 'ARRAY';
- # First we compose a list of which aliases are used in restrictions
- # (i.e. conditions/order/grouping/etc). Since we do not have
- # introspectable SQLA, we fall back to ugly scanning of raw SQL for
- # WHERE, and for pieces of ORDER BY in order to determine which aliases
- # need to appear in the resulting sql.
- # It may not be very efficient, but it's a reasonable stop-gap
- # Also unqualified column names will not be considered, but more often
- # than not this is actually ok
- #
- # In the same loop we enumerate part of the selection aliases, as
- # it requires the same sqla hack for the time being
- my ( $restrict_aliases, $select_aliases, $prefetch_aliases ) = ( {}, {}, {} );
- {
- # produce stuff unquoted, so it can be scanned
- my $sql_maker = $self->sql_maker;
- local $sql_maker->{quote_char};
- my $sep = $self->_sql_maker_opts->{name_sep} || '.';
- $sep = "\Q$sep\E";
+ # what we will return
+ my $alias_map;
- my $non_prefetch_select_sql = $sql_maker->_recurse_fields ($select) || '';
- my $prefetch_select_sql = $sql_maker->_recurse_fields ($attrs->{_prefetch_select}) || '';
- my $where_sql = $sql_maker->where ($where);
- my $group_by_sql = $sql_maker->_order_by({
- map { $_ => $attrs->{$_} } qw/group_by having/
- }) || '';
- my @non_prefetch_order_by_chunks = (map
- { ref $_ ? $_->[0] : $_ }
- $sql_maker->_order_by_chunks ($attrs->{order_by})
- );
+ # see what aliases are there to work with
+ my $alias_list;
+ my @from = @$from; # if I don't copy weird shit happens
+ for my $j (@from) {
+ $j = $j->[0] if ref $j eq 'ARRAY';
+ $alias_list->{$j->{-alias}} = $j;
+ }
+ # set up a botched SQLA
+ my $sql_maker = $self->sql_maker;
+ my $sep = quotemeta ($self->_sql_maker_opts->{name_sep} || '.');
+ local $sql_maker->{quote_char}; # so that we can regex away
- for my $alias (keys %original_join_info) {
- my $seen_re = qr/\b $alias $sep/x;
- for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) {
- if ($piece =~ $seen_re) {
- $restrict_aliases->{$alias} = 1;
- }
- }
+ my $select_sql = $sql_maker->_recurse_fields ($select);
+ my $where_sql = $sql_maker->where ($where);
+ my $group_by_sql = $sql_maker->_order_by({
+ map { $_ => $attrs->{$_} } qw/group_by having/
+ });
+ my @order_by_chunks = (map
+ { ref $_ ? $_->[0] : $_ }
+ $sql_maker->_order_by_chunks ($attrs->{order_by})
+ );
- if ($non_prefetch_select_sql =~ $seen_re) {
- $select_aliases->{$alias} = 1;
- }
+ # match every alias to the sql chunks above
+ for my $alias (keys %$alias_list) {
+ my $al_re = qr/\b $alias $sep/x;
- if ($prefetch_select_sql =~ $seen_re) {
- $prefetch_aliases->{$alias} = 1;
- }
-
+ for my $piece ($where_sql, $group_by_sql) {
+ $alias_map->{restrict}{$alias} = 1 if ($piece =~ $al_re);
}
- }
- # Add any non-left joins to the restriction list (such joins are indeed restrictions)
- for my $j (values %original_join_info) {
- my $alias = $j->{-alias} or next;
- $restrict_aliases->{$alias} = 1 if (
- (not $j->{-join_type})
- or
- ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
- );
- }
-
- # mark all join parents as mentioned
- # (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too )
- for my $collection ($restrict_aliases, $select_aliases) {
- for my $alias (keys %$collection) {
- $collection->{$_} = 1
- for (@{ $original_join_info{$alias}{-join_path} || [] });
+ for my $piece ($select_sql, @order_by_chunks ) {
+ $alias_map->{select}{$alias} = 1 if ($piece =~ $al_re);
}
}
- return ( $restrict_aliases, $select_aliases, $prefetch_aliases );
-}
-sub _choose_aliases_to_include {
- my ( $self, $from, $where, $inner_select, $inner_attrs, $outer_select,
- $outer_attrs ) = @_;
-
- my %original_join_info = map { $_->[0]{-alias} => $_->[0] } (@$from);
- # decide which parts of the join will remain in either part of
- # the outer/inner query
-
- # First we compose a list of which aliases are used in restrictions
- # (i.e. conditions/order/grouping/etc). Since we do not have
- # introspectable SQLA, we fall back to ugly scanning of raw SQL for
- # WHERE, and for pieces of ORDER BY in order to determine which aliases
- # need to appear in the resulting sql.
- # It may not be very efficient, but it's a reasonable stop-gap
- # Also unqualified column names will not be considered, but more often
- # than not this is actually ok
- #
- # In the same loop we enumerate part of the selection aliases, as
- # it requires the same sqla hack for the time being
- my ($restrict_aliases, $select_aliases, $prefetch_aliases);
- {
- # produce stuff unquoted, so it can be scanned
- my $sql_maker = $self->sql_maker;
- local $sql_maker->{quote_char};
- my $sep = $self->_sql_maker_opts->{name_sep} || '.';
- $sep = "\Q$sep\E";
-
- my $non_prefetch_select_sql = $sql_maker->_recurse_fields ($inner_select);
- my $prefetch_select_sql = $sql_maker->_recurse_fields ($outer_attrs->{_prefetch_select});
- my $where_sql = $sql_maker->where ($where);
- my $group_by_sql = $sql_maker->_order_by({
- map { $_ => $inner_attrs->{$_} } qw/group_by having/
- });
- my @non_prefetch_order_by_chunks = (map
- { ref $_ ? $_->[0] : $_ }
- $sql_maker->_order_by_chunks ($inner_attrs->{order_by})
- );
-
-
- for my $alias (keys %original_join_info) {
- my $seen_re = qr/\b $alias $sep/x;
-
- for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) {
- if ($piece =~ $seen_re) {
- $restrict_aliases->{$alias} = 1;
- }
- }
-
- if ($non_prefetch_select_sql =~ $seen_re) {
- $select_aliases->{$alias} = 1;
- }
-
- if ($prefetch_select_sql =~ $seen_re) {
- $prefetch_aliases->{$alias} = 1;
- }
-
- }
- }
-
# Add any non-left joins to the restriction list (such joins are indeed restrictions)
- for my $j (values %original_join_info) {
+ for my $j (values %$alias_list) {
my $alias = $j->{-alias} or next;
- $restrict_aliases->{$alias} = 1 if (
+ $alias_map->{restrict}{$alias} = 1 if (
(not $j->{-join_type})
or
($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
@@ -335,13 +254,14 @@
# mark all join parents as mentioned
# (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too )
- for my $collection ($restrict_aliases, $select_aliases) {
- for my $alias (keys %$collection) {
- $collection->{$_} = 1
- for (@{ $original_join_info{$alias}{-join_path} || [] });
+ for my $collection (qw/restrict select/) {
+ for my $alias (keys %{$alias_map->{$collection}||{}}) {
+ $alias_map->{$collection}{$_} = 1
+ for (@{ $alias_list->{$alias}{-join_path} || [] });
}
}
- return ( $restrict_aliases, $select_aliases, $prefetch_aliases );
+
+ return $alias_map;
}
sub _resolve_ident_sources {
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