[Bast-commits] r9461 - in DBIx-Class/0.08/trunk: . lib/DBIx/Class
lib/DBIx/Class/Storage t/lib/DBICTest/Schema
t/sqlahacks/limit_dialects
ribasushi at dev.catalyst.perl.org
ribasushi at dev.catalyst.perl.org
Sun May 30 22:17:29 GMT 2010
Author: ribasushi
Date: 2010-05-30 23:17:29 +0100 (Sun, 30 May 2010)
New Revision: 9461
Added:
DBIx-Class/0.08/trunk/t/sqlahacks/limit_dialects/generic_subq.t
Modified:
DBIx-Class/0.08/trunk/Changes
DBIx-Class/0.08/trunk/lib/DBIx/Class/SQLAHacks.pm
DBIx-Class/0.08/trunk/lib/DBIx/Class/Storage/DBI.pm
DBIx-Class/0.08/trunk/t/lib/DBICTest/Schema/BooksInLibrary.pm
DBIx-Class/0.08/trunk/t/sqlahacks/limit_dialects/toplimit.t
Log:
Rewrite GenericSubQ from SQLA::L to be actually useful
Since it now works it is no longer necessary to turn on softlimit when genericsubq is detected
Switch all sprintf()ed limit/offset specs to unsigned integers
Lower the default rows-without-offset to 2^32
Modified: DBIx-Class/0.08/trunk/Changes
===================================================================
--- DBIx-Class/0.08/trunk/Changes 2010-05-30 09:40:12 UTC (rev 9460)
+++ DBIx-Class/0.08/trunk/Changes 2010-05-30 22:17:29 UTC (rev 9461)
@@ -22,6 +22,9 @@
resultsets
- MSSQL limits now don't require nearly as many applications of
the unsafe_subselect_ok attribute, due to optimized queries
+ - Support for Generic Subquery limit "emulation" - awfully slow
+ and inefficient but works on almost any db, and is preferred
+ to a soft-limit
- Fix as_subselect_rs to not inject resultset class-wide where
conditions outside of the resulting subquery
- Fix nasty potentially data-eating bug when deleting/updating
Modified: DBIx-Class/0.08/trunk/lib/DBIx/Class/SQLAHacks.pm
===================================================================
--- DBIx-Class/0.08/trunk/lib/DBIx/Class/SQLAHacks.pm 2010-05-30 09:40:12 UTC (rev 9460)
+++ DBIx-Class/0.08/trunk/lib/DBIx/Class/SQLAHacks.pm 2010-05-30 22:17:29 UTC (rev 9461)
@@ -48,29 +48,25 @@
# !!! THIS IS ALSO HORRIFIC !!! /me ashamed
#
-# generate inner/outer select lists for various limit dialects
+# Generates inner/outer select lists for various limit dialects
# which result in one or more subqueries (e.g. RNO, Top, RowNum)
# Any non-root-table columns need to have their table qualifier
# turned into a column alias (otherwise names in subqueries clash
# and/or lose their source table)
#
-# returns inner/outer strings of SQL QUOTED selectors with aliases
+# Returns inner/outer strings of SQL QUOTED selectors with aliases
# (to be used in whatever select statement), and an alias index hashref
# of QUOTED SEL => QUOTED ALIAS pairs (to maybe be used for string-subst
-# higher up)
-#
-# If the $scan_order option is supplied, it signals that the limit dialect
-# needs to order the outer side of the query, which in turn means that the
-# inner select needs to bring out columns used in implicit (non-selected)
-# orders, and the order condition itself needs to be realiased to the proper
-# names in the outer query.
-#
-# In this case ($scan_order os true) we also return a hashref (order doesn't
-# matter) of QUOTED EXTRA-SEL => QUOTED ALIAS pairs, which is a list of extra
-# selectors that do *not* exist in the original select list
+# higher up).
+# If an order_by is supplied, the inner select needs to bring out columns
+# used in implicit (non-selected) orders, and the order condition itself
+# needs to be realiased to the proper names in the outer query. Thus we
+# also return a hashref (order doesn't matter) of QUOTED EXTRA-SEL =>
+# QUOTED ALIAS pairs, which is a list of extra selectors that do *not*
+# exist in the original select list
sub _subqueried_limit_attrs {
- my ($self, $rs_attrs, $scan_order) = @_;
+ my ($self, $rs_attrs) = @_;
croak 'Limit dialect implementation usable only in the context of DBIC (missing $rs_attrs)'
unless ref ($rs_attrs) eq 'HASH';
@@ -104,10 +100,12 @@
$in_sel_index->{$sql_sel}++;
$in_sel_index->{$self->_quote ($sql_alias)}++ if $sql_alias;
-# this *may* turn out to be necessary, not sure yet
-# my ($sql_unqualified_sel) = $sql_sel =~ / $re_sep (.+) $/x
-# if ! ref $s;
-# $in_sel_index->{$sql_unqualified_sel}++;
+ # record unqualified versions too, so we do not have
+ # to reselect the same column twice (in qualified and
+ # unqualified form)
+ if (! ref $s && $sql_sel =~ / $re_sep (.+) $/x) {
+ $in_sel_index->{$1}++;
+ }
}
@@ -130,20 +128,20 @@
}
}
+ # see if the order gives us anything
my %extra_order_sel;
- if ($scan_order) {
- for my $chunk ($self->_order_by_chunks ($rs_attrs->{order_by})) {
- # order with bind
- $chunk = $chunk->[0] if (ref $chunk) eq 'ARRAY';
- $chunk =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
+ for my $chunk ($self->_order_by_chunks ($rs_attrs->{order_by})) {
+ # order with bind
+ $chunk = $chunk->[0] if (ref $chunk) eq 'ARRAY';
+ $chunk =~ s/\s+ (?: ASC|DESC ) \s* $//ix;
- next if $in_sel_index->{$chunk};
+ next if $in_sel_index->{$chunk};
- $extra_order_sel{$chunk} ||= $self->_quote (
- 'ORDER__BY__' . scalar keys %extra_order_sel
- );
- }
+ $extra_order_sel{$chunk} ||= $self->_quote (
+ 'ORDER__BY__' . scalar keys %extra_order_sel
+ );
}
+
return (
(map { join (', ', @$_ ) } (
\@in_sel,
@@ -163,9 +161,8 @@
or croak "Unrecognizable SELECT: $sql";
# get selectors, and scan the order_by (if any)
- my ($in_sel, $out_sel, $alias_map, $extra_order_sel) = $self->_subqueried_limit_attrs (
- $rs_attrs, 'scan_order_by',
- );
+ my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
+ = $self->_subqueried_limit_attrs ( $rs_attrs );
# make up an order if none exists
my $requested_order = (delete $rs_attrs->{order_by}) || $self->_rno_default_order;
@@ -207,7 +204,7 @@
SELECT $mid_sel, ROW_NUMBER() OVER( $rno_ord ) AS $idx_name FROM (
SELECT $in_sel ${sql}${group_having}
) $qalias
-) $qalias WHERE $idx_name BETWEEN %d AND %d
+) $qalias WHERE $idx_name BETWEEN %u AND %u
EOS
@@ -229,10 +226,10 @@
return sprintf ('SELECT %s%s%s%s',
$offset
- ? sprintf ('SKIP %d ', $offset)
+ ? sprintf ('SKIP %u ', $offset)
: ''
,
- sprintf ('FIRST %d ', $rows),
+ sprintf ('FIRST %u ', $rows),
$sql,
$self->_parse_rs_attrs ($rs_attrs),
);
@@ -246,9 +243,9 @@
or croak "Unrecognizable SELECT: $sql";
return sprintf ('SELECT %s%s%s%s',
- sprintf ('FIRST %d ', $rows),
+ sprintf ('FIRST %u ', $rows),
$offset
- ? sprintf ('SKIP %d ', $offset)
+ ? sprintf ('SKIP %u ', $offset)
: ''
,
$sql,
@@ -276,7 +273,7 @@
SELECT $outsel, ROWNUM $idx_name FROM (
SELECT $insel ${sql}${order_group_having}
) $qalias
-) $qalias WHERE $idx_name BETWEEN %d AND %d
+) $qalias WHERE $idx_name BETWEEN %u AND %u
EOS
@@ -294,7 +291,7 @@
# get selectors
my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
- = $self->_subqueried_limit_attrs ($rs_attrs, 'outer_order_by');
+ = $self->_subqueried_limit_attrs ($rs_attrs);
my $requested_order = delete $rs_attrs->{order_by};
@@ -359,7 +356,7 @@
my $quoted_rs_alias = $self->_quote ($rs_attrs->{alias});
- $sql = sprintf ('SELECT TOP %d %s %s %s %s',
+ $sql = sprintf ('SELECT TOP %u %s %s %s %s',
$rows + ($offset||0),
$in_sel,
$sql,
@@ -367,7 +364,7 @@
$order_by_inner,
);
- $sql = sprintf ('SELECT TOP %d %s FROM ( %s ) %s %s',
+ $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
$rows,
$mid_sel,
$sql,
@@ -375,7 +372,7 @@
$order_by_reversed,
) if $offset;
- $sql = sprintf ('SELECT TOP %d %s FROM ( %s ) %s %s',
+ $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
$rows,
$out_sel,
$sql,
@@ -383,10 +380,116 @@
$order_by_requested,
) if ( ($offset && $order_by_requested) || ($mid_sel ne $out_sel) );
+ $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
return $sql;
}
+# This is the most evil limit "dialect" (more of a hack) for *really*
+# stupid databases. It works by ordering the set by some unique column,
+# and calculating amount of rows that have a less-er value (thus
+# emulating a RowNum-like index). Of course this implies the set can
+# only be ordered by a single unique columns.
+sub _GenericSubQ {
+ my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
+ my $root_rsrc = $rs_attrs->{_rsroot_source_handle}->resolve;
+ my $root_tbl_name = $root_rsrc->name;
+
+ # mangle the input sql as we will be replacing the selector
+ $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
+ or croak "Unrecognizable SELECT: $sql";
+
+ my ($order_by, @rest) = do {
+ local $self->{quote_char};
+ $self->_order_by_chunks ($rs_attrs->{order_by})
+ };
+
+ unless (
+ $order_by
+ &&
+ ! @rest
+ &&
+ ( ! ref $order_by
+ ||
+ ( ref $order_by eq 'ARRAY' and @$order_by == 1 )
+ )
+ ) {
+ croak (
+ 'Generic Subquery Limit does not work on resultsets without an order, or resultsets '
+ . 'with complex order criteria (multicolumn and/or functions). Provide a single, '
+ . 'unique-column order criteria.'
+ );
+ }
+
+ ($order_by) = @$order_by if ref $order_by;
+
+ $order_by =~ s/\s+ ( ASC|DESC ) \s* $//ix;
+ my $direction = lc ($1 || 'asc');
+
+ my ($unq_sort_col) = $order_by =~ /(?:^|\.)([^\.]+)$/;
+
+ my $inf = $root_rsrc->storage->_resolve_column_info (
+ $rs_attrs->{from}, [$order_by, $unq_sort_col]
+ );
+
+ my $ord_colinfo = $inf->{$order_by} || croak "Unable to determine source of order-criteria '$order_by'";
+
+ if ($ord_colinfo->{-result_source}->name ne $root_tbl_name) {
+ croak "Generic Subquery Limit order criteria can be only based on the root-source '"
+ . $root_rsrc->source_name . "' (aliased as '$rs_attrs->{alias}')";
+ }
+
+ # make sure order column is qualified
+ $order_by = "$rs_attrs->{alias}.$order_by"
+ unless $order_by =~ /^$rs_attrs->{alias}\./;
+
+ my $is_u;
+ my $ucs = { $root_rsrc->unique_constraints };
+ for (values %$ucs ) {
+ if (@$_ == 1 && "$rs_attrs->{alias}.$_->[0]" eq $order_by) {
+ $is_u++;
+ last;
+ }
+ }
+ croak "Generic Subquery Limit order criteria column '$order_by' must be unique (no unique constraint found)"
+ unless $is_u;
+
+ my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
+ = $self->_subqueried_limit_attrs ($rs_attrs);
+
+ my $cmp_op = $direction eq 'desc' ? '>' : '<';
+ my $count_tbl_alias = 'rownum__emulation';
+
+ my $order_group_having = $self->_parse_rs_attrs($rs_attrs);
+
+ # add the order supplement (if any) as this is what will be used for the outer WHERE
+ $in_sel .= ", $_" for keys %{$extra_order_sel||{}};
+
+ $sql = sprintf (<<EOS,
+SELECT $out_sel
+ FROM (
+ SELECT $in_sel ${sql}${order_group_having}
+ ) %s
+WHERE ( SELECT COUNT(*) FROM %s %s WHERE %s $cmp_op %s ) %s
+EOS
+ ( map { $self->_quote ($_) } (
+ $rs_attrs->{alias},
+ $root_tbl_name,
+ $count_tbl_alias,
+ "$count_tbl_alias.$unq_sort_col",
+ $order_by,
+ )),
+ $offset
+ ? sprintf ('BETWEEN %u AND %u', $offset, $offset + $rows - 1)
+ : sprintf ('< %u', $rows )
+ ,
+ );
+
+ $sql =~ s/\s*\n\s*/ /g; # easier to read in the debugger
+ return $sql;
+}
+
+
# While we're at it, this should make LIMIT queries more efficient,
# without digging into things too deeply
sub _find_syntax {
Modified: DBIx-Class/0.08/trunk/lib/DBIx/Class/Storage/DBI.pm
===================================================================
--- DBIx-Class/0.08/trunk/lib/DBIx/Class/Storage/DBI.pm 2010-05-30 09:40:12 UTC (rev 9460)
+++ DBIx-Class/0.08/trunk/lib/DBIx/Class/Storage/DBI.pm 2010-05-30 22:17:29 UTC (rev 9461)
@@ -1922,19 +1922,13 @@
}
# adjust limits
- if (
- $attrs->{software_limit}
- ||
- $sql_maker->_default_limit_syntax eq "GenericSubQ"
- ) {
- $attrs->{software_limit} = 1;
- }
- else {
+ if (defined $attrs->{rows}) {
$self->throw_exception("rows attribute must be positive if present")
- if (defined($attrs->{rows}) && !($attrs->{rows} > 0));
-
+ unless $attrs->{rows} > 0;
+ }
+ elsif (defined $attrs->{offset}) {
# MySQL actually recommends this approach. I cringe.
- $attrs->{rows} = 2**48 if not defined $attrs->{rows} and defined $attrs->{offset};
+ $attrs->{rows} = 2**32;
}
my @limit;
Modified: DBIx-Class/0.08/trunk/t/lib/DBICTest/Schema/BooksInLibrary.pm
===================================================================
--- DBIx-Class/0.08/trunk/t/lib/DBICTest/Schema/BooksInLibrary.pm 2010-05-30 09:40:12 UTC (rev 9460)
+++ DBIx-Class/0.08/trunk/t/lib/DBICTest/Schema/BooksInLibrary.pm 2010-05-30 22:17:29 UTC (rev 9461)
@@ -27,6 +27,8 @@
);
__PACKAGE__->set_primary_key('id');
+__PACKAGE__->add_unique_constraint (['title']);
+
__PACKAGE__->resultset_attributes({where => { source => "Library" } });
__PACKAGE__->belongs_to ( owner => 'DBICTest::Schema::Owners', 'owner' );
Added: DBIx-Class/0.08/trunk/t/sqlahacks/limit_dialects/generic_subq.t
===================================================================
--- DBIx-Class/0.08/trunk/t/sqlahacks/limit_dialects/generic_subq.t (rev 0)
+++ DBIx-Class/0.08/trunk/t/sqlahacks/limit_dialects/generic_subq.t 2010-05-30 22:17:29 UTC (rev 9461)
@@ -0,0 +1,125 @@
+use strict;
+use warnings;
+
+use Test::More;
+use lib qw(t/lib);
+use DBICTest;
+use DBIC::SqlMakerTest;
+
+my $schema = DBICTest->init_schema;
+
+$schema->storage->_sql_maker->limit_dialect ('GenericSubQ');
+
+my $rs = $schema->resultset ('BooksInLibrary')->search ({}, {
+ '+columns' => [{ owner_name => 'owner.name' }],
+ join => 'owner',
+ rows => 2,
+ order_by => 'me.title',
+});
+
+is_same_sql_bind(
+ $rs->as_query,
+ '(
+ SELECT id, source, owner, title, price,
+ owner_name
+ FROM (
+ SELECT me.id, me.source, me.owner, me.title, me.price,
+ owner.name AS owner_name
+ FROM books me
+ JOIN owners owner ON owner.id = me.owner
+ WHERE ( source = ? )
+ ORDER BY me.title
+ ) me
+ WHERE
+ (
+ SELECT COUNT(*)
+ FROM books rownum__emulation
+ WHERE rownum__emulation.title < me.title
+ ) < 2
+ )',
+ [ [ 'source', 'Library' ] ],
+);
+
+is_deeply (
+ [ $rs->get_column ('title')->all ],
+ ['Best Recipe Cookbook', 'Dynamical Systems'],
+ 'Correct columns selected with rows',
+);
+
+$schema->storage->_sql_maker->quote_char ('"');
+$schema->storage->_sql_maker->name_sep ('.');
+
+$rs = $schema->resultset ('BooksInLibrary')->search ({}, {
+ order_by => { -desc => 'title' },
+ '+select' => ['owner.name'],
+ '+as' => ['owner.name'],
+ join => 'owner',
+ rows => 3,
+ offset => 1,
+});
+
+is_same_sql_bind(
+ $rs->as_query,
+ '(
+ SELECT "id", "source", "owner", "title", "price",
+ "owner__name"
+ FROM (
+ SELECT "me"."id", "me"."source", "me"."owner", "me"."title", "me"."price",
+ "owner"."name" AS "owner__name"
+ FROM "books" "me"
+ JOIN "owners" "owner" ON "owner"."id" = "me"."owner"
+ WHERE ( "source" = ? )
+ ORDER BY "title" DESC
+ ) "me"
+ WHERE
+ (
+ SELECT COUNT(*)
+ FROM "books" "rownum__emulation"
+ WHERE "rownum__emulation"."title" > "me"."title"
+ ) BETWEEN 1 AND 3
+ )',
+ [ [ 'source', 'Library' ] ],
+);
+
+is_deeply (
+ [ $rs->get_column ('title')->all ],
+ [ 'Dynamical Systems', 'Best Recipe Cookbook' ],
+ 'Correct columns selected with rows',
+);
+
+$rs = $schema->resultset ('BooksInLibrary')->search ({}, {
+ order_by => 'title',
+ 'select' => ['owner.name'],
+ 'as' => ['owner_name'],
+ join => 'owner',
+ offset => 1,
+});
+
+is_same_sql_bind(
+ $rs->as_query,
+ '(
+ SELECT "owner_name"
+ FROM (
+ SELECT "owner"."name" AS "owner_name", "title"
+ FROM "books" "me"
+ JOIN "owners" "owner" ON "owner"."id" = "me"."owner"
+ WHERE ( "source" = ? )
+ ORDER BY "title"
+ ) "me"
+ WHERE
+ (
+ SELECT COUNT(*)
+ FROM "books" "rownum__emulation"
+ WHERE "rownum__emulation"."title" < "me"."title"
+ ) BETWEEN 1 AND 4294967295
+ )',
+ [ [ 'source', 'Library' ] ],
+);
+
+is_deeply (
+ [ $rs->get_column ('owner_name')->all ],
+ [ ('Newton') x 2 ],
+ 'Correct columns selected with rows',
+);
+
+done_testing;
Modified: DBIx-Class/0.08/trunk/t/sqlahacks/limit_dialects/toplimit.t
===================================================================
--- DBIx-Class/0.08/trunk/t/sqlahacks/limit_dialects/toplimit.t 2010-05-30 09:40:12 UTC (rev 9460)
+++ DBIx-Class/0.08/trunk/t/sqlahacks/limit_dialects/toplimit.t 2010-05-30 22:17:29 UTC (rev 9461)
@@ -153,19 +153,19 @@
SELECT TOP 2 id, source, owner, title, price
FROM (
SELECT TOP 2
- id, source, owner, title, price, ORDER__BY__1
+ id, source, owner, title, price
FROM (
SELECT TOP 5
- me.id, me.source, me.owner, me.title, me.price, title AS ORDER__BY__1
+ me.id, me.source, me.owner, me.title, me.price
FROM books me
JOIN owners owner ON owner.id = me.owner
WHERE ( source = ? )
GROUP BY title
ORDER BY title
) me
- ORDER BY ORDER__BY__1 DESC
+ ORDER BY title DESC
) me
- ORDER BY ORDER__BY__1
+ ORDER BY title
) me
JOIN owners owner ON owner.id = me.owner
WHERE ( source = ? )
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