how to set query timeout for oracle 11 in ruby - ruby-on-rails

Question

I saw other threads stating how to do it for mySql, and even how to do it in java, but not how to set the query timeout in ruby.
I'm trying to use the setQueryTimeout function in Jruby using OJDBC7, but can't find how to do it in ruby. I've tried the following:
#c.connection.instance_variable_get(:#connection).instance_variable_set(:#query_timeout, 1)
#c.connection.instance_variable_get(:#connection).instance_variable_set(:#read_timeout, 1)
#c.connection.setQueryTimeout(1)
I also tried modifying my database.yml file to include
adapter: jdbc
driver: oracle.jdbc.driver.OracleDriver
timeout: 1
none of the above had any effect, other then the setQueryTimeout which threw a method error.
Any help would be great

Answer 1

So I found a way to make it work, but I don't like it. It's very hackish and orphans queries on the database, but it at least allows my app to continue executing. I would still love to find a way to cancel the statement so i'm not orphaning queries that take longer then 10 seconds.
query_thread = Thread.new {
#execute query
}
begin
Timeout::timeout(10) do
query_thread.join()
end
rescue
Thread.kill(query_thread)
results = Array.new
end

Answer 2

Query timeout on Oracle-DB works for me with Rails 4 and JRuby
With JRuby you can use JBDC-function statement.setQueryTimeout to define query timeout.
Suddenly this requires patching of oracle-enhanced_adapter as shown below.
This example is an implementation of iterator-query without storing result in array, which also uses query timeout.
# hold open SQL-Cursor and iterate over SQL-result without storing whole result in Array
# Peter Ramm, 02.03.2016
# expand class by getter to allow access on internal variable #raw_statement
ActiveRecord::ConnectionAdapters::OracleEnhancedJDBCConnection::Cursor.class_eval do
def get_raw_statement
#raw_statement
end
end
# Class extension by Module-Declaration : module ActiveRecord, module ConnectionAdapters, module OracleEnhancedDatabaseStatements
# does not work as Engine with Winstone application server, therefore hard manipulation of class ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter
# and extension with method iterate_query
ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter.class_eval do
# Method comparable with ActiveRecord::ConnectionAdapters::OracleEnhancedDatabaseStatements.exec_query,
# but without storing whole result in memory
def iterate_query(sql, name = 'SQL', binds = [], modifier = nil, query_timeout = nil, &block)
type_casted_binds = binds.map { |col, val|
[col, type_cast(val, col)]
}
log(sql, name, type_casted_binds) do
cursor = nil
cached = false
if without_prepared_statement?(binds)
cursor = #connection.prepare(sql)
else
unless #statements.key? sql
#statements[sql] = #connection.prepare(sql)
end
cursor = #statements[sql]
binds.each_with_index do |bind, i|
col, val = bind
cursor.bind_param(i + 1, type_cast(val, col), col)
end
cached = true
end
cursor.get_raw_statement.setQueryTimeout(query_timeout) if query_timeout
cursor.exec
if name == 'EXPLAIN' and sql =~ /^EXPLAIN/
res = true
else
columns = cursor.get_col_names.map do |col_name|
#connection.oracle_downcase(col_name).freeze
end
fetch_options = {:get_lob_value => (name != 'Writable Large Object')}
while row = cursor.fetch(fetch_options)
result_hash = {}
columns.each_index do |index|
result_hash[columns[index]] = row[index]
row[index] = row[index].strip if row[index].class == String # Remove possible 0x00 at end of string, this leads to error in Internet Explorer
end
result_hash.extend SelectHashHelper
modifier.call(result_hash) unless modifier.nil?
yield result_hash
end
end
cursor.close unless cached
nil
end
end #iterate_query
end #class_eval
class SqlSelectIterator
def initialize(stmt, binds, modifier, query_timeout)
#stmt = stmt
#binds = binds
#modifier = modifier # proc for modifikation of record
#query_timeout = query_timeout
end
def each(&block)
# Execute SQL and call block for every record of result
ActiveRecord::Base.connection.iterate_query(#stmt, 'sql_select_iterator', #binds, #modifier, #query_timeout, &block)
end
end
Use above class SqlSelectIterator like this example:
SqlSelectIterator.new(stmt, binds, modifier, query_timeout).each do |record|
process(record)
end