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 (file)
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;