From: Dobrica Pavlinusic <dpavlin@rot13.org>
Date: Fri, 4 Jul 2003 18:23:00 +0000 (+0000)
Subject: uses memory as cache
X-Git-Url: http://git.rot13.org/?p=webpac;a=commitdiff_plain;h=5b1f4ecfdae5de328c3b9bb961f119b64df19a0b

uses memory as cache


git-svn-id: file:///home/dpavlin/private/svn/webpac/trunk@60 13eb9ef6-21d5-0310-b721-a9d68796d827
---

diff --git a/index_DBI_cache.pm b/index_DBI_cache.pm
new file mode 100644
index 0000000..9613f61
--- /dev/null
+++ b/index_DBI_cache.pm
@@ -0,0 +1,218 @@
+#
+# this file implements index functions using DBI
+# and huge amounts of memory for cache speedup
+#
+
+package index_DBI;
+use strict qw(vars);
+use vars qw($Count);
+use HTML::Entities;
+
+use DBI;
+
+my %Table;	# index tables which where visited in this run
+my %sth_cache;	# cache prepared statements
+
+# cache var
+my $c_table;
+my $c_count;
+
+sub new {
+	my $class = shift;
+	my $self = {};
+	bless($self, $class);
+
+	my $dbd = shift || die "need dbi_dbd= in [global] section of configuration file";
+	my $dsn = shift || die "need dbi_dsn= in [global] section of configuration file";
+	my $user = shift || die "need dbi_user= in [global] section of configuration file";
+	my $passwd = shift || die "need dbi_passwd= in [global] section of configuration file";
+
+	$self->{dbh} = DBI->connect("DBI:$dbd:$dsn",$user,$passwd) || die $DBI::errstr;
+	# begin transaction
+	$self->{dbh}->begin_work || die $self->{dbh}->errstr();
+
+	$Count++;
+
+	return $self;
+}
+
+sub delete_and_create {
+	my $self = shift;
+
+	my $field = shift;
+
+#print "#### delete_and_create($field)\n";
+
+	$self->{dbh}->commit;
+
+	my $sql = "select count(*) from $field";
+	my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
+# FIX: this is not a good way to check if table exists!
+	if ($sth->execute() && $sth->fetchrow_hashref) {
+		my $sql = "drop table $field";
+		$self->{dbh}->begin_work;
+		my $sth = $self->{dbh}->do($sql) || die "SQL: $sql ".$self->{dbh}->errstr();
+		$self->{dbh}->commit;
+	}
+	$sql = "create table $field (
+			item varchar(255),
+			ident varchar(255),
+			count int,
+			ord int,
+			primary key (item,ident)
+		)";
+
+	$self->{dbh}->begin_work;
+	$sth = $self->{dbh}->do($sql); # || warn "SQL: $sql ".$self->{dbh}->errstr();
+	$self->{dbh}->commit;
+
+	$self->{dbh}->begin_work;
+}
+
+sub insert {
+	my $self = shift;
+
+	my $field = shift;
+	my $index_data = shift || print STDERR "\$index->insert($field,NULL,...)";
+	my $ident = shift || '';	# e.g. library id
+
+	if (! $index_data) {
+		print STDERR "\$index->insert() -- no value to insert\n";
+		return;
+	}
+
+	if (! $Table{$field}) {
+		$self->delete_and_create($field);
+
+		my $sql = "select item from $field where upper(item)=upper(?)";
+		$sth_cache{$field."select"} = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
+
+		$sql = "insert into $field (item,ident,count) values (?,?,?)";
+		$sth_cache{$field."insert"} = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
+
+		$sql = "update $field set count = count + 1 where item = ? and ident = ?";
+		$sth_cache{$field."update"} = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
+	}
+	$Table{$field}++;
+
+	#$sth_cache{$field."select"}->execute($index_data) || die "cache: $field select; ".$self->{dbh}->errstr();
+	$index_data = substr($index_data,0,255);
+	my $uc = uc($index_data);
+	if (! $c_table->{$field}->{$ident}->{$uc}) {
+		$sth_cache{$field."insert"}->execute($index_data,$ident,0) || die "cache: $field insert; ".$self->{dbh}->errstr();
+#print stderr "in index: $index_data\n";
+		$c_table->{$field}->{$ident}->{$uc} = $index_data;
+		$c_count->{$field}->{$ident}->{$uc} = 1;
+	} else {
+		$c_count->{$field}->{$ident}->{$uc}++;
+	}
+}
+
+sub check {
+	my $self = shift;
+
+	my $field = shift;
+
+	my $sql = "select count(*) from $field";
+
+	my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
+	$sth->execute() || die "sql: $sql; ".$self->{dbh}->errstr();
+
+	my ($total) = $sth->fetchrow_array();
+
+	return $total;
+}
+
+
+sub fetch {
+	my $self = shift;
+
+	my $field = shift;
+	my $what = shift || 'item';	# 'item,ident'
+	my $where = shift;
+
+	my $from_ord = shift || 0;
+	my $rows = shift || 10;
+
+	my @sql_args;
+
+	my $sql = "select $what,ord from $field";
+
+	if ($where) {
+		my $sql2 = " select ord from $field where upper($what) like upper(?)||'%'";
+		my $sth = $self->{dbh}->prepare($sql2) || die "sql2: $sql2; ".$self->{dbh}->errstr();
+
+		$sth->execute($where) || die "sql2: $sql2; ".$self->{dbh}->errstr();
+		if (my $row = $sth->fetchrow_hashref) {
+			$from_ord += $row->{ord} - 1;
+		}
+	}
+	$sql .= " order by ord limit $rows offset $from_ord";
+
+	my $sth = $self->{dbh}->prepare($sql) || die "prepare: $sql; ".$self->{dbh}->errstr();
+	$sth->execute() || die "execute: $sql; ".$self->{dbh}->errstr();
+	my @arr;
+	while (my $row = $sth->fetchrow_hashref) {
+		$row->{item} = HTML::Entities::encode($row->{item},'<>&"');
+		push @arr,$row;
+	}
+	return @arr;
+}
+
+sub close {
+	my $self = shift;
+
+
+	# re-create ord column (sorted order) in table
+	sub create_ord {
+
+		my $table = shift;
+
+		$self->{dbh}->begin_work || die $self->{dbh}->errstr();
+
+		my $sql = "select oid from $table order by upper(item)";
+		my $sth = $self->{dbh}->prepare($sql) || die "sql: $sql; ".$self->{dbh}->errstr();
+		$sql = "update $table set ord=? where oid=?";
+		my $sth_update = $self->{dbh}->prepare($sql) || die "sql: $sql; ".$self->{dbh}->errstr();
+		$sth->execute() || die "sql: $sql; ".$self->{dbh}->errstr();
+		my $ord = 1;
+		while (my $row = $sth->fetchrow_hashref) {
+			$sth_update->execute($ord++,$row->{oid});
+		}
+
+		$self->{dbh}->commit || die $self->{dbh}->errstr();
+	}
+	#--- end of sub
+
+	if ($self->{dbh}) {
+
+		# commit
+		$self->{dbh}->commit || die $self->{dbh}->errstr();
+
+		foreach my $table (keys %Table) {
+# FIX
+print STDERR "creating ord for $table...\n";
+			create_ord($table);
+			undef $sth_cache{$table."select"};
+			undef $sth_cache{$table."insert"};
+			undef $sth_cache{$table."update"};
+# XXX
+#		$sth_cache{$field."update"}->execute($index_data,$ident) || die "cache: $field update; ".$self->{dbh}->errstr();
+		}
+
+		$self->{dbh}->disconnect;
+		undef $self->{dbh};
+	}
+}
+
+END {
+	$Count--;
+	print STDERR "index_DBI fatal error: \$index->close() not called... $Count references left!\n" if ($Count > 0);
+	# FIX: debug output
+#	print STDERR "usage\ttable\n";
+#	foreach (keys %Table) {
+#		print STDERR $Table{$_},"\t$_\n";
+#	}
+}
+
+1;