X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FSQLMaker%2FLimitDialects.pm;h=ec9300aece7326f395c70dd24929602a6982d2a9;hb=cb3e87f5f530f76ddf46924e6ec6bd3cc414ccd3;hp=3df6daa3ca9e75cdec3697b0edd7d305440afee7;hpb=d3cd93b9aafcf291b29dc5d2167aab0349d5155e;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/SQLMaker/LimitDialects.pm b/lib/DBIx/Class/SQLMaker/LimitDialects.pm index 3df6daa..ec9300a 100644 --- a/lib/DBIx/Class/SQLMaker/LimitDialects.pm +++ b/lib/DBIx/Class/SQLMaker/LimitDialects.pm @@ -279,7 +279,7 @@ EOS $rs_attrs->{order_by} and $rs_attrs->{_rsroot_rsrc}->storage->_order_by_is_stable( - $rs_attrs->{from}, $rs_attrs->{order_by} + @{$rs_attrs}{qw/from order_by where/} ) ) { push @{$self->{limit_bind}}, [ $self->__total_bindtype => $offset + $rows ], [ $self->__offset_bindtype => $offset + 1 ]; @@ -331,10 +331,11 @@ sub _prep_for_skimming_limit { if ($sq_attrs->{order_by_requested}) { $self->throw_exception ( 'Unable to safely perform "skimming type" limit with supplied unstable order criteria' - ) unless $rs_attrs->{_rsroot_rsrc}->schema->storage->_order_by_is_stable( + ) unless ($rs_attrs->{_rsroot_rsrc}->schema->storage->_order_by_is_stable( $rs_attrs->{from}, - $requested_order - ); + $requested_order, + $rs_attrs->{where}, + )); $inner_order = $requested_order; } @@ -357,9 +358,10 @@ sub _prep_for_skimming_limit { for my $ch ($self->_order_by_chunks ($inner_order)) { $ch = $ch->[0] if ref $ch eq 'ARRAY'; - $ch =~ s/\s+ ( ASC|DESC ) \s* $//ix; - my $dir = uc ($1||'ASC'); - push @out_chunks, \join (' ', $ch, $dir eq 'ASC' ? 'DESC' : 'ASC' ); + ($ch, my $is_desc) = $self->_split_order_chunk($ch); + + # !NOTE! outside chunks come in reverse order ( !$is_desc ) + push @out_chunks, { ($is_desc ? '-asc' : '-desc') => \$ch }; } $sq_attrs->{order_by_middle} = $self->_order_by (\@out_chunks); @@ -382,18 +384,6 @@ sub _prep_for_skimming_limit { # Whatever order bindvals there are, they will be realiased and # reselected, and need to show up at end of the initial inner select push @{$self->{select_bind}}, @{$self->{order_bind}}; - - # if this is a part of something bigger, we need to add back all - # the extra order_by's, as they may be relied upon by the outside - # of a prefetch or something - if ($rs_attrs->{_is_internal_subuery}) { - $sq_attrs->{selection_outer} .= sprintf ", $extra_order_sel->{$_} AS $_" - for sort - { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} } - grep { $_ !~ /[^\w\-]/ } # ignore functions - keys %$extra_order_sel - ; - } } # and this is order re-alias magic @@ -517,32 +507,6 @@ sub _FetchFirst { return $sql; } -=head2 RowCountOrGenericSubQ - -This is not exactly a limit dialect, but more of a proxy for B. -If no $offset is supplied the limit is simply performed as: - - SET ROWCOUNT $limit - SELECT ... - SET ROWCOUNT 0 - -Otherwise we fall back to L - -=cut - -sub _RowCountOrGenericSubQ { - my $self = shift; - my ($sql, $rs_attrs, $rows, $offset) = @_; - - return $self->_GenericSubQ(@_) if $offset; - - return sprintf <<"EOF", $rows, $sql, $self->_parse_rs_attrs( $rs_attrs ); -SET ROWCOUNT %d -%s %s -SET ROWCOUNT 0 -EOF -} - =head2 GenericSubQ SELECT * FROM ( @@ -556,8 +520,11 @@ This is the most evil limit "dialect" (more of a hack) for I stupid databases. It works by ordering the set by some unique column, and calculating the amount of rows that have a less-er value (thus emulating a L-like index). Of course this implies the set can only be ordered by a single unique -column. Also note that this technique can be and often is B. +column. + +Also note that this technique can be and often is B. You +may have much better luck using L +instead. Currently used by B, due to lack of any other option. @@ -566,59 +533,106 @@ sub _GenericSubQ { my ($self, $sql, $rs_attrs, $rows, $offset) = @_; my $root_rsrc = $rs_attrs->{_rsroot_rsrc}; - my $root_tbl_name = $root_rsrc->name; - my ($first_order_by) = do { + # Explicitly require an order_by + # GenSubQ is slow enough as it is, just emulating things + # like in other cases is not wise - make the user work + # to shoot their DBA in the foot + my $supplied_order = delete $rs_attrs->{order_by} or $self->throw_exception ( + 'Generic Subquery Limit does not work on resultsets without an order. Provide a stable, ' + . 'root-table-based order criteria.' + ); + + my $usable_order_ci = $root_rsrc->storage->_main_source_order_by_portion_is_stable( + $root_rsrc, + $supplied_order, + $rs_attrs->{where}, + ) or $self->throw_exception( + 'Generic Subquery Limit can not work with order criteria based on sources other than the current one' + ); + +### +### +### we need to know the directions after we figured out the above - reextract *again* +### this is eyebleed - trying to get it to work at first + my @order_bits = do { local $self->{quote_char}; local $self->{order_bind}; - map { ref $_ ? $_->[0] : $_ } $self->_order_by_chunks ($rs_attrs->{order_by}) - } or $self->throw_exception ( - 'Generic Subquery Limit does not work on resultsets without an order. Provide a single, ' - . 'unique-column order criteria.' - ); + map { ref $_ ? $_->[0] : $_ } $self->_order_by_chunks ($supplied_order) + }; - $first_order_by =~ s/\s+ ( ASC|DESC ) \s* $//ix; - my $direction = lc ($1 || 'asc'); + # truncate to what we'll use + $#order_bits = ( (keys %$usable_order_ci) - 1 ); - my ($first_ord_alias, $first_ord_col) = $first_order_by =~ /^ (?: ([^\.]+) \. )? ([^\.]+) $/x; + # @order_bits likely will come back quoted (due to how the prefetch + # rewriter operates + # Hence supplement the column_info lookup table with quoted versions + if ($self->quote_char) { + $usable_order_ci->{$self->_quote($_)} = $usable_order_ci->{$_} + for keys %$usable_order_ci; + } - $self->throw_exception(sprintf - "Generic Subquery Limit order criteria can be only based on the root-source '%s'" - . " (aliased as '%s')", $root_rsrc->source_name, $rs_attrs->{alias}, - ) if ($first_ord_alias and $first_ord_alias ne $rs_attrs->{alias}); +# calculate the condition + my $count_tbl_alias = 'rownum__emulation'; + my $root_alias = $rs_attrs->{alias}; + my $root_tbl_name = $root_rsrc->name; - $first_ord_alias ||= $rs_attrs->{alias}; + my (@unqualified_names, @qualified_names, @is_desc, @new_order_by); - $self->throw_exception( - "Generic Subquery Limit first order criteria '$first_ord_col' must be unique" - ) unless $root_rsrc->_identifying_column_set([$first_ord_col]); - - my $sq_attrs = do { - # perform the mangling only using the very first order crietria - # (the one we care about) - local $rs_attrs->{order_by} = $first_order_by; - $self->_subqueried_limit_attrs ($sql, $rs_attrs); - }; + for my $bit (@order_bits) { - my $cmp_op = $direction eq 'desc' ? '>' : '<'; - my $count_tbl_alias = 'rownum__emulation'; + ($bit, my $is_desc) = $self->_split_order_chunk($bit); - my ($order_sql, @order_bind) = do { - local $self->{order_bind}; - my $s = $self->_order_by (delete $rs_attrs->{order_by}); - ($s, @{$self->{order_bind}}); + push @is_desc, $is_desc; + push @unqualified_names, $usable_order_ci->{$bit}{-colname}; + push @qualified_names, $usable_order_ci->{$bit}{-fq_colname}; + + push @new_order_by, { ($is_desc ? '-desc' : '-asc') => $usable_order_ci->{$bit}{-fq_colname} }; }; - my $group_having_sql = $self->_parse_rs_attrs($rs_attrs); - my $in_sel = $sq_attrs->{selection_inner}; + my (@where_cond, @skip_colpair_stack); + for my $i (0 .. $#order_bits) { + my $ci = $usable_order_ci->{$order_bits[$i]}; + + my ($subq_col, $main_col) = map { "$_.$ci->{-colname}" } ($count_tbl_alias, $root_alias); + my $cur_cond = { $subq_col => { ($is_desc[$i] ? '>' : '<') => { -ident => $main_col } } }; + + push @skip_colpair_stack, [ + { $main_col => { -ident => $subq_col } }, + ]; + + # we can trust the nullability flag because + # we already used it during _id_col_set resolution + # + if ($ci->{is_nullable}) { + push @{$skip_colpair_stack[-1]}, { $main_col => undef, $subq_col=> undef }; + + $cur_cond = [ + { + ($is_desc[$i] ? $subq_col : $main_col) => { '!=', undef }, + ($is_desc[$i] ? $main_col : $subq_col) => undef, + }, + { + $subq_col => { '!=', undef }, + $main_col => { '!=', undef }, + -and => $cur_cond, + }, + ]; + } - # add the order supplement (if any) as this is what will be used for the outer WHERE - $in_sel .= ", $_" for keys %{$sq_attrs->{order_supplement}}; + push @where_cond, { '-and', => [ @skip_colpair_stack[0..$i-1], $cur_cond ] }; + } + +# reuse the sqlmaker WHERE, this will not be returning binds + my $counted_where = do { + local $self->{where_bind}; + $self->where(\@where_cond); + }; +# construct the rownum condition by hand my $rownum_cond; if ($offset) { $rownum_cond = 'BETWEEN ? AND ?'; - push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset ], [ $self->__total_bindtype => $offset + $rows - 1] @@ -626,30 +640,51 @@ sub _GenericSubQ { } else { $rownum_cond = '< ?'; - push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ] ; } - # even though binds in order_by make no sense here (the rs needs to be - # ordered by a unique column first) - pass whatever there may be through - # anyway - push @{$self->{limit_bind}}, @order_bind; +# and what we will order by inside + my $inner_order_sql = do { + local $self->{order_bind}; + + my $s = $self->_order_by (\@new_order_by); + + $self->throw_exception('Inner gensubq order may not contain binds... something went wrong') + if @{$self->{order_bind}}; + + $s; + }; + +### resume originally scheduled programming +### +### + + # we need to supply the order for the supplements to be properly calculated + my $sq_attrs = $self->_subqueried_limit_attrs ( + $sql, { %$rs_attrs, order_by => \@new_order_by } + ); + + my $in_sel = $sq_attrs->{selection_inner}; + + # add the order supplement (if any) as this is what will be used for the outer WHERE + $in_sel .= ", $_" for sort keys %{$sq_attrs->{order_supplement}}; + + my $group_having_sql = $self->_parse_rs_attrs($rs_attrs); + return sprintf (" SELECT $sq_attrs->{selection_outer} FROM ( SELECT $in_sel $sq_attrs->{query_leftover}${group_having_sql} ) %s -WHERE ( SELECT COUNT(*) FROM %s %s WHERE %s $cmp_op %s ) $rownum_cond -$order_sql +WHERE ( SELECT COUNT(*) FROM %s %s $counted_where ) $rownum_cond +$inner_order_sql ", map { $self->_quote ($_) } ( $rs_attrs->{alias}, $root_tbl_name, $count_tbl_alias, - "$count_tbl_alias.$first_ord_col", - "$first_ord_alias.$first_ord_col", )); } @@ -764,12 +799,12 @@ sub _subqueried_limit_attrs { 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* $//ix; + ($chunk) = $self->_split_order_chunk($chunk); next if $in_sel_index->{$chunk}; $extra_order_sel->{$chunk} ||= $self->_quote ( - 'ORDER__BY__' . scalar keys %{$extra_order_sel||{}} + 'ORDER__BY__' . sprintf '%03d', scalar keys %{$extra_order_sel||{}} ); }