groupstats.pl: Redo level (-l) query, gain speedup.

Do the work in the application, using two separate SQL
queries, instead of trying to optimize the single
query in vain ...

Thanks to Juliane. :)

Fixes #16.

Signed-off-by: Thomas Hochstein <thh@inter.net>
This commit is contained in:
Thomas Hochstein 2010-10-31 21:43:18 +01:00
parent 404c1acdc8
commit b802bc3d29

View file

@ -155,13 +155,17 @@ if (!defined($Options{'b'}) and !defined($Options{'l'})) {
} else {
$Level = '>';
};
# push level and $StartMonth,$EndMonth - again - to Params
# FIXME -- together with the query (see below)
push @Params,$Options{'l'};
push @Params,$StartMonth,$EndMonth;
# prepare query: get number of postings per group from groups table for given months and
# FIXME -- this query is ... in dire need of impromevent
$DBQuery = $DBHandle->prepare(sprintf("SELECT month,newsgroup,postings FROM %s.%s WHERE newsgroup IN (SELECT newsgroup FROM %s.%s WHERE %s GROUP BY newsgroup HAVING MAX(postings) %s ?) AND %s ORDER BY newsgroup,month",$Conf{'DBDatabase'},$Conf{'DBTableGrps'},$Conf{'DBDatabase'},$Conf{'DBTableGrps'},$WhereClause,$Level,$WhereClause));
# prepare and execute query: get list of newsgroups meeting level condition
$DBQuery = $DBHandle->prepare(sprintf("SELECT newsgroup FROM %s.%s WHERE %s GROUP BY newsgroup HAVING MAX(postings) %s ?",$Conf{'DBDatabase'},$Conf{'DBTableGrps'},$WhereClause,$Level));
$DBQuery->execute($StartMonth,$EndMonth,@GroupList,$Options{'l'})
or die sprintf("$MySelf: E: Can't get groups data for %s to %s from %s.%s: %s\n",$StartMonth,$EndMonth,$Conf{'DBDatabase'},$Conf{'DBTableGrps'},$DBI::errstr);
# add newsgroups to a comma-seperated list ready for IN(...) query
my $GroupList;
while (my ($Newsgroup) = $DBQuery->fetchrow_array) {
$GroupList .= ',' if (defined($GroupList) and $GroupList ne '');
$GroupList .= "'$Newsgroup'";
};
$DBQuery = $DBHandle->prepare(sprintf("SELECT month,newsgroup,postings FROM %s.%s WHERE newsgroup IN (%s) AND %s ORDER BY newsgroup,month",$Conf{'DBDatabase'},$Conf{'DBTableGrps'},$GroupList,$WhereClause));
};
# execute query