discourse-legacysite-perl/site/slowtwitch.com/cgi-bin/articles/GT/SQL/Search/INTERNAL/Search.pm
2024-06-17 21:49:12 +10:00

605 lines
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Perl

# ==================================================================
# Gossamer Threads Module Library - http://gossamer-threads.com/
#
# GT::SQL::Indexer
# Author : Aki Mimoto
# CVS Info : 087,071,086,086,085
# $Id: Search.pm,v 1.18 2004/08/28 03:53:47 jagerman Exp $
#
# Copyright (c) 2004 Gossamer Threads Inc. All Rights Reserved.
# ==================================================================
#
# Description:
# Class used to make changes to tables and create tables.
#
package GT::SQL::Search::INTERNAL::Search;
# ------------------------------------------------------------------------------
use strict;
use vars qw/@ISA $VERSION $DEBUG $ATTRIBS /;
use GT::SQL::Search::Base::Search;
@ISA = qw( GT::SQL::Search::Base::Search );
# ------------------------------------------------------------------------------
# Preamble information related to the object
$DEBUG = 0;
$VERSION = sprintf "%d.%03d", q$Revision: 1.18 $ =~ /(\d+)\.(\d+)/;
$ATTRIBS = {
# the max number of links that can be handled by UNION before it should simply
# shunt the searching pipe to NONINDEXED system
'union_shunt_threshold' => '5000',
'phrase_shunt_threshold' => '1000',
};
################################################################################
# Internal functions
################################################################################
sub load {
shift;
return GT::SQL::Search::INTERNAL::Search->new(@_)
}
sub _query {
# ------------------------------------------------------------------------------
# this just checks to ensure that the words are not all search keywords
#
my ( $self, $input, $buckets ) = @_;
# calculate wordids and frequencies
foreach ( keys %$buckets ) {
$buckets->{$_} = $self->get_wordids( $buckets->{$_}, ( /phrase/ ? "phrases" : "keywords" ) );
}
# the following is a bit tricky and will be replaced however, if the number
# of results from a union is more than the maximum shunt value, it will
# simply do a nonindexed query
if ( $buckets->{keywords} ) {
my $rec = _count_frequencies( $buckets->{keywords} );
my $count = 0;
foreach ( values %$rec ) { $count += $_; }
if ($count > $self->{union_shunt_threshold}) {
$self->debug_dumper("Too many results using internal search, falling back to nonindexed. Counts are: ", $rec) if ($self->{_debug});
return $self->alternate_driver_query( 'NONINDEXED', $input );
}
}
# Now test the phrases. Just due to how the phrase searching works, the queries
# can grow in size extremely rapidly, and slowdown the search. So the limit for
# phrase searching is separate as it requires a different cutoff value than
# the keyword search which is usually much lower!
if ($buckets->{phrases}) {
foreach my $phrase ( keys %{$buckets->{phrases} || {} } ) {
my $rec = _count_frequencies( $buckets->{phrases}->{$phrase}->{word_info} );
my ( $count ) = sort values %$rec; # Get smallest frequency.
if ( $count > $self->{phrase_shunt_threshold} ) {
$self->debug_dumper("Too many results using internal search, falling back to nonindexed. Counts are: ", $rec) if ($self->{_debug});
return $self->alternate_driver_query( 'NONINDEXED', $input );
}
}
}
if ($buckets->{phrases_must}) {
foreach my $phrase ( keys %{$buckets->{phrases_must} || {} } ) {
my $rec = _count_frequencies( $buckets->{phrases_must}->{$phrase}->{word_info} );
my ( $count ) = sort values %$rec; # Get smallest frequency.
if ( $count > $self->{phrase_shunt_threshold} ) {
$self->debug_dumper("Too many results using internal search, falling back to nonindexed. Counts are: ", $rec) if ($self->{_debug});
return $self->alternate_driver_query( 'NONINDEXED', $input );
}
}
}
return $self->SUPER::_query( $input, $buckets );
}
sub _count_frequencies {
# ------------------------------------------------------------------------------
my $word_info = shift;
my $rec = {};
foreach my $word ( keys %$word_info ) {
my $freq = 0;
foreach ( values %{$word_info->{$word}->{word_info}} ) {
$freq += $_;
}
$rec->{$word} = $freq;
}
return $rec;
}
sub _table_names {
# ------------------------------------------------------------------------------
# return the table names
#
my $self = shift;
my $table = $self->{table}->name() or return $self->error('NOSCHEMA', 'FATAL');
my $wtable = $table . '_Word_List';
my $stable = $table . '_Score_List';
return ( $table, $wtable, $stable);
}
sub _word_infos {
# ------------------------------------------------------------------------------
# get the word ids and frequencies
#
my $self = shift;
my $word_infos = shift;
my $rec = {};
foreach my $word ( keys %$word_infos ) {
my $wi = $word_infos->{$word}->{word_info};
$rec->{$word} = [ map { [ $_, $wi->{$_} ] } keys %$wi ];
}
return $rec;
}
sub _union_query {
# ------------------------------------------------------------------------------
# Takes a list of words and gets all words that match
# returns { itemid -> score } of hits that match
#
my $self = shift;
my $words = shift;
my $results = shift || {};
my ( $query, $where, $db, $word_infos );
my ( $table, $wtable, $stable) = $self->_table_names();
$db = $self->{table}->{driver} or return $self->error( 'NODRIVER', 'FATAL' );
$word_infos = $self->_word_infos( $words ) or return $results;
return $results unless (keys %{$word_infos});
$self->debug_dumper( "Getting words: ", $words) if ($self->{_debug});
# build the where clause
my @word_ids;
foreach my $word_synonym_list ( values %$word_infos ) {
next unless ( $word_synonym_list );
foreach my $word_id ( @{$word_synonym_list }) {
next unless ( ref $word_id eq 'ARRAY' ); # ensure it's a reference
push @word_ids, $word_id->[0]; # we need to shed the word quantities
}
}
return $results unless ( @word_ids );
$where = 'Word_ID IN(' . join(",", @word_ids) . ")";
# build the query
$query = qq!
SELECT Item_ID, SUM(Score)
FROM $stable
WHERE
$where
GROUP BY Item_ID
!;
$self->debug( "Union Query: $query" ) if ($self->{_debug});
# prepare the query
my $sth = $db->prepare( $query ) or return;
$sth->execute() or return;
# get the results
my %word_infos = $sth->fetchall_list;
# merge the current result set into found
foreach my $item ( keys %{$results} ) {
$word_infos{$item} += $results->{$item};
};
return \%word_infos;
}
sub _intersect_query {
# ------------------------------------------------------------------------------
# Takes a list of words and gets all words that match all the keywords
# returns { itemid -> score } of hits that match
#
my $self = shift;
my $words = shift;
my $results = shift || {};
$words or return $results;
keys %{$words} or return $results;
my ( $query, $where, $db, $word_infos, $word_hits );
my ( $table, $wtable, $stable) = $self->_table_names();
# have we left any of our words out?
$db = $self->{table}->{driver} or return $self->error( 'NODRIVER', 'FATAL' );
$word_infos = $self->_word_infos( $words ) or return {};
if ( keys %{$word_infos} < keys %{$words} ) {
return {};
}
$self->debug_dumper( "Keyword Intersect words: ", $word_infos ) if ($self->{_debug});
# take the words and get a hash of the word scores
foreach my $word ( keys %{$word_infos} ) {
my $total_freq = 0;
foreach my $word_synonyms ( @{$word_infos->{$word}} ) {
$total_freq += $word_synonyms->[1];
}
$word_hits->{$word} = $total_freq or return;
}
# so now, sort out the words from lowest frequency to highest frequency
my @search_order = sort { $word_hits->{$a} <=> $word_hits->{$b} } keys %{$word_hits};
$self->debug_dumper( "Searching words in this order: ", \@search_order) if ($self->{_debug});
# find out how we're going to handle the searching, if the first elements
################################################################################
### The following part is for smaller intersect subsets
################################################################################
my $intersect = $results;
foreach my $word ( @search_order ) {
# setup the where clause to get all the words associated
my $where = "Word_ID in(" . join(",", map( { $_->[0] } @{$word_infos->{$word}} )) . ")";
# setup the intersect for the previous if required. for iterative intersecting
if ( keys %{$intersect} ) {
$where .= " AND Item_ID in(" . join(",",keys %{$intersect}) . ")";
}
# make the database engine work a little bit
$query = qq!
SELECT Item_ID, SUM(Score) AS Score
FROM $stable
WHERE
$where
GROUP BY Item_ID
!;
$self->debug( "Intersect Query: $query" ) if ($self->{_debug});
my $intersect_sth = $db->prepare( $query );
$intersect_sth->execute();
# get a list of all the matches
my $matches = $intersect_sth->fetchall_arrayref();
$self->debug_dumper( "Matches found for $word: ", $matches ) if ($self->{_debug});
# go through all the matches and intersect them
my %tmp = ();
foreach my $row ( @{$matches} ) {
my ( $itemid, $score ) = @{$row};
$intersect->{$itemid} ||= 0;
$tmp{ $itemid } = $intersect->{$itemid} + $score;
}
# inform the system of that development
%tmp or return;
$intersect = \%tmp;
}
return $intersect;
}
sub _disjoin_query {
#------------------------------------------------------------
my $self = shift;
my $words = shift;
my $results = shift || {};
$words or return $results;
my ( $query, $where, $db, $word_infos, $word_hits );
my ( $table, $wtable, $stable) = $self->_table_names();
$db = $self->{table}->{driver} or return $results;
# have we left any of our words out?
$word_infos = $self->_word_infos( $words ) or return $results;
# if ( keys %{$word_infos} < keys %{$words} ) {
# return $results;
# }
# take the words and get a hash of the word scores
foreach my $word ( keys %{$word_infos} ) {
my $total_freq = 0;
foreach my $word_synonyms ( $word_infos->{$word} ) {
$total_freq += ( $word_synonyms->[0] || 0 );
}
# if the value is null this mean there is actually no results, whoops!
$total_freq and $word_hits->{$word} = $total_freq;
}
# so now, sort out the words from lowest frequency to highest frequency
my @search_order = sort { $word_hits->{$b} <=> $word_hits->{$b} } keys %{$word_hits};
$self->debug_dumper( "Disjoining words in the following order: ", \@search_order) if ($self->{_debug});
################################################################################
### This following part is for smaller disjoin presets
################################################################################
foreach my $word ( @search_order ) {
# setup the where clause to get all the words associated
my $where = "Word_ID in(" . join(",", map( { $_->[0] } @{$word_infos->{$word}} )) . ")";
# setup the intersect for the previous if required. for iterative intersecting
if ( keys %{$results} ) {
$where .= " AND Item_ID in(" . join(",", keys %{$results}) . ")";
}
# make the database engine work a little bit
$query = qq!
SELECT Item_ID
FROM $stable
WHERE
$where
GROUP BY Item_ID
!;
$self->debug($query) if ($self->{_debug});
my $intersect_sth = $db->prepare( $query );
$intersect_sth->execute();
# get a list of all the matches
my $matches = $intersect_sth->fetchall_arrayref();
# strip the matches from the current result set
foreach my $word ( map { $_->[0] } @{$matches}) {
delete $results->{$word};
}
}
return $results;
}
sub _phrase_disjoin_query {
#------------------------------------------------------------
# subtracts the found phrases from the list
my $self = shift;
my $phrases = shift;
my $results = shift || {};
$phrases or return $results;
foreach my $phrase ( values %{$phrases} ) {
my $temp = $self->_get_phrase( $phrase->{'phrase'}, $phrase->{word_info} );
# perform disjoin
foreach my $itemid ( keys %{$temp} ) {
$self->debug( "Deleting $itemid from list" ) if ($self->{_debug});
delete $results->{$itemid};
}
}
return $results;
}
sub _phrase_intersect_query {
#------------------------------------------------------------
# intersects phrases together
my $self = shift;
my $phrases = shift;
my $results = shift || {};
$phrases or return $results;
foreach my $phrase ( values %{$phrases} ) {
my $temp = $self->_get_phrase( $phrase->{'phrase'}, $phrase->{word_info} );
# perform intersect
foreach my $itemid ( keys %{$temp} ) {
$temp->{$itemid} += $results->{$itemid} || 0;
}
$results = $temp;
}
return $results;
}
sub _phrase_query {
#------------------------------------------------------------
# this is a phrase union query
my $self = shift;
my $phrases = shift or return;
my $results = shift || {};
foreach my $phrase ( values %{$phrases} ) {
$self->debug_dumper( "Unioning: ", $phrase ) if ($self->{_debug});
$results = $self->_get_phrase( $phrase->{'phrase'}, $phrase->{word_info}, $results );
}
return $results;
}
sub _get_phrase {
#------------------------------------------------------------
my $self = shift;
my $wordlist= shift;
my $word_info = shift;
my $results = shift || {};
$wordlist or return $results;
my ( $query, $where, $db, $word_infos, %word_hits );
my ( $table, $wtable, $stable) = $self->_table_names();
my ($pk) = $self->{table}->pk;
$self->debug_dumper( "Getting words: ", $wordlist ) if ($self->{_debug});
# get all the word ids that we want to handle
$db = $self->{table}->{driver} or return $self->error( 'NODRIVER', 'FATAL' );
$word_infos = $self->_word_infos( $word_info ) or return;
$self->debug_dumper( "Word infos: ", $word_infos ) if ($self->{_debug});
# take the words and get a hash of the word scores
foreach my $word ( keys %{$word_infos} ) {
@{$word_infos->{$word} || []} or return;
my $total_freq = 0;
foreach my $word_synonyms ( @{$word_infos->{$word}} ) {
$total_freq += $word_synonyms->[1];
}
# if the value is null this mean there is actually no results, whoops!
$word_hits{$word} = $total_freq;
}
$self->debug_dumper( "With synonyms tallied: ", \%word_hits ) if ($self->{_debug});
# so now, setup the order of search
my $i = 0;
my %word_order = map { $_ => $i++ } @{$wordlist};
my @search_order = sort { $word_hits{$a} <=> $word_hits{$b} } keys %word_hits;
$self->debug_dumper( "Word search order: ", \@search_order ) if ($self->{_debug});
################################################################################
### This following part is for smaller phrases
################################################################################
# start getting words in order of their frequency
my %matches = ();
my $index = 0;
foreach my $word ( @search_order ) {
# setup the where clause for the individual words, firstly
if ( keys %matches ) {
my $vector = $word_order{$word} - $index;
$where = '(';
$where =
'(' .
join(
" OR ",
map(
"Item_ID = $_ AND Word_Pos IN(" . join(",", map $_->[0] + $vector, @{$matches{$_}}) . ')',
keys %matches
)
) .
") AND ";
}
else {
$where = '';
}
$where .= "Word_ID IN(" . ( join ",", map { $_->[0] || () } @{$word_infos->{$word}} or return $results ) . ')';
$query = qq!
SELECT
Item_ID, Score, Word_Pos
FROM
$stable
WHERE
$where
!;
$self->debug( "Phrase get for '$word': " . $query ) if ($self->{_debug});
my $sth = $db->prepare( $query );
$sth->execute();
%matches = ();
while (my $hit = $sth->fetchrow_arrayref) {
push @{$matches{$hit->[0]}}, [ $hit->[2], $hit->[1] ];
}
# If there are no values stored in %matches, it means that for
# this keyword, there have been no hits based upon position.
# In that case, terminate and return a null result
keys %matches or last;
# where were we in the string?
$index = $word_order{$word};
}
# now tally up all the scores and merge the new records in
foreach my $itemid ( keys %matches ) {
my $score = 0;
foreach my $sub_total ( @{$matches{$itemid}} ) {
$score += $sub_total->[1];
}
$results->{$itemid} += $score;
}
return $results;
}
sub get_wordids {
# ------------------------------------------------------------------------------
# Get a list of words
#
my $self = shift;
my $elements = shift or return;
my $mode = lc shift || 'keywords';
if ( $mode eq 'keywords' ) {
$elements = $self->_get_wordid($elements);
}
else {
foreach my $phrase ( keys %$elements ) {
my $results = $self->_get_wordid({
map { ($_ => { substring => 0 }) } @{$elements->{$phrase}->{phrase}}
});
$elements->{$phrase}->{word_info} = $results;
}
}
return $elements;
}
sub _get_wordid {
# ------------------------------------------------------------------------------
# Get a list of words
#
my $self = shift;
my $words = shift;
my $tbl = $self->{table};
my ( $table, $wtable, $stable) = $self->_table_names();
foreach my $word ( keys %$words ) {
my $query =
qq!SELECT Word_ID, Frequency FROM $wtable WHERE Word LIKE '! .
quotemeta($word) .
( $words->{$word}->{substring} ? '%' : '' ) .
"'";
my $sth = $tbl->do_query($query) or next;
my $tmp = { $sth->fetchall_list };
$words->{$word}->{word_info} = $tmp;
}
return $words;
}
##
# Internal Use
# $self->_cgi_to_hash ($in);
# --------------------------
# Creates a hash ref from a cgi object.
##
sub _cgi_to_hash {
my ($self, $cgi) = @_;
$cgi and UNIVERSAL::can($cgi, 'param') or return $self->error(NODRIVER => 'FATAL');
my @keys = $cgi->param;
my $result = {};
foreach my $key (@keys) {
my @values = $cgi->param($key);
if (@values == 1) { $result->{$key} = $values[0] }
else { $result->{$key} = \@values }
}
return $result;
}
1;