From 22b2db48c005be1d1b87dd6b58f830a2a74d2108 Mon Sep 17 00:00:00 2001 From: Robin Houston Date: Thu, 19 Jan 2012 13:50:26 +0000 Subject: Limit Xapian wildcard expansions Wildcard searches in Xapian can expand uncontrollably, consuming all available RAM and crashing the server. This has been a real problem on WhatDoTheyKnow.com. The underlying issue is tracked in http://trac.xapian.org/ticket/350 This changeset imposes a limit on wildcard expansion. The type-ahead search will first try a wildcard query, and if that fails because of too much expansion will fall back to a plain non-wildcard search. --- app/controllers/application_controller.rb | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) (limited to 'app/controllers/application_controller.rb') diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb index 0c8544932..eae27c667 100644 --- a/app/controllers/application_controller.rb +++ b/app/controllers/application_controller.rb @@ -385,11 +385,24 @@ class ApplicationController < ActionController::Base ActsAsXapian.readable_init old_default_op = ActsAsXapian.query_parser.default_op ActsAsXapian.query_parser.default_op = Xapian::Query::OP_OR - user_query = ActsAsXapian.query_parser.parse_query( - query, - Xapian::QueryParser::FLAG_LOVEHATE | Xapian::QueryParser::FLAG_PARTIAL | - Xapian::QueryParser::FLAG_SPELLING_CORRECTION) - xapian_requests = ActsAsXapian::Search.new([model], query, options, user_query) + begin + user_query = ActsAsXapian.query_parser.parse_query( + query.strip + '*', + Xapian::QueryParser::FLAG_LOVEHATE | Xapian::QueryParser::FLAG_WILDCARD | + Xapian::QueryParser::FLAG_SPELLING_CORRECTION) + xapian_requests = ActsAsXapian::Search.new([model], query, options, user_query) + rescue RuntimeError => e + if e.message =~ /^QueryParserError: Wildcard/ + # Wildcard expands to too many terms + logger.info "Wildcard query '#{query.strip + '*'}' caused: #{e.message}" + + user_query = ActsAsXapian.query_parser.parse_query( + query, + Xapian::QueryParser::FLAG_LOVEHATE | + Xapian::QueryParser::FLAG_SPELLING_CORRECTION) + xapian_requests = ActsAsXapian::Search.new([model], query, options, user_query) + end + end ActsAsXapian.query_parser.default_op = old_default_op end return xapian_requests -- cgit v1.2.3