[Rails] out of memory generating huge csv from active record

I am trying to work with generating really large CSV files from
active record. (This is actually an end case test however) I am trying
this with
a set of active records that is 700000 records which is just a test
case that I have, though it is very large. The type of find() below is
supposed to work in pages and not have all active records in memory. I
get an out of memory error (see stack dump below). The print of the
count also never comes out.

I got that info from here in the first part of "nailing down the root
cause"
http://www.engineyard.com/blog/2009/thats-not-a-memory-leak-its-bloat/

I am also using faster_csv which is supposed to not use as much memory
from soem other google searches.

I am using jruby 1.6.7 (ruby 1.8.7) and active record 2.3 (which I
assume corresponds to rails 2,.3)

on the call here, attr =
{:conditions=>["cdr_guid_id = :cdr_guid_id", {:cdr_guid_id=>30}]}

def self.export_to_csv(attr)
self.set_client(attr[:client])
# client is our own thing,
# and not part of active record find()
attr.delete(:client)

cnt = 0
if hrec = self.find(:first)
CSV.generate(path) do |ofil|
ofil << hrec.visible_attributes.keys
self.find(:all, attr).each do |rec|
cnt += 1
puts cnt.to_s if cnt % 100 == 0
ofil << rec.visible_attributes.keys.map{|col|
rec.send(col) }
end
end
end
end





===================



[2012-05-07 17:06:35] ERROR Java::JavaLang::OutOfMemoryError: Java
heap space

java.nio.channels.spi.AbstractInterruptibleChannel.begin(Unknown
Source)

May 7, 2012 5:06:35 PM com.microsoft.sqlserver.jdbc.TDSParser
throwUnexpectedTok
enException
SEVERE: ConnectionID:2: getNextResult: Encountered unexpected unknown
token (0x0
)
May 7, 2012 5:06:35 PM com.microsoft.sqlserver.jdbc.TDSReader
throwInvalidTDS
SEVERE: ConnectionID:2 got unexpected value in TDS response at offset:
0
ActiveRecord::StatementInvalid - Java::JavaLang::OutOfMemoryError:
Java heap spa
ce: SELECT * FROM record_set_3764 WHERE (cdr_guid_id = 30) :
C:/Users/lgu/vendor/activerecord-2.3.8/lib/active_record/
connection_adapters/abst
ract_adapter.rb:221:in `log'
C:/Users/lgu/vendor/activerecord-jdbc-adapter-0.9.7-java/lib/
active_record/connec
tion_adapters/jdbc_adapter.rb:655:in `select'
C:/Users/lgu/vendor/activerecord-jdbc-adapter-0.9.7-java/lib/
active_record/connec
tion_adapters/jdbc_adapter.rb:567:in `jdbc_select_all'
C:/Users/lgu/vendor/activerecord-2.3.8/lib/active_record/
connection_adapters/abst
ract/query_cache.rb:62:in `select_all_with_query_cache'
C:/Users/lgu/vendor/activerecord-2.3.8/lib/active_record/base.rb:
664:in `find_by_
sql'
C:/Users/lgu/vendor/activerecord-2.3.8/lib/active_record/base.rb:
1578:in `find_ev
ery'
C:/Users/lgu//vendor/activerecord-2.3.8/lib/active_record/base.rb:
618:in `find'
./recordset_models.rb:465:in `export_to_csv'
c:/jruby-1.6.7/lib/ruby/1.8/csv.rb:330:in `open_writer'
c:/jruby-1.6.7/lib/ruby/1.8/csv.rb:677:in `generate'
c:/jruby-1.6.7/lib/ruby/1.8/csv.rb:329:in `open_writer'
c:/jruby-1.6.7/lib/ruby/1.8/csv.rb:111:in `generate'
./recordset_models.rb:459:in `export_to_csv'
./recordset_models.rb:368:in `export_to_csv'
recordset.rb:72:in `__file__'
org/jruby/RubyProc.java:270:in `call'
org/jruby/RubyMethod.java:129:in `call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:1151:in
`compile!'
org/jruby/RubyKernel.java:2045:in `instance_eval'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:724:in
`route_eval'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:708:in
`route!'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:758:in
`process_route'
org/jruby/RubyKernel.java:1183:in `catch'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:755:in
`process_route'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:707:in
`route!'
org/jruby/RubyArray.java:1615:in `each'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:706:in
`route!'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:843:in
`dispatch!'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:644:in
`call!'
org/jruby/RubyKernel.java:2045:in `instance_eval'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:808:in
`invoke'
org/jruby/RubyKernel.java:1183:in `catch'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:808:in
`invoke'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:644:in
`call!'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:629:in
`call'
C:/Users/lgu/nakajima-rack-flash-0.1.0/lib/rack/flash.rb:154:in
`call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/rack-1.3.1/lib/rack/session/
abstract/id.r
b:195:in `context'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/rack-1.3.1/lib/rack/session/
abstract/id.r
b:190:in `call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/rack-1.3.1/lib/rack/head.rb:
9:in `call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/rack-1.3.1/lib/rack/
commonlogger.rb:20:in
`call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
showexceptions.
rb:21:in `call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/rack-1.3.1/lib/rack/
methodoverride.rb:24:
in `call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:1272:in
`call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:1303:in
`synchronize'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/sinatra-1.2.6/lib/sinatra/
base.rb:1272:in
`call'
c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/rack-1.3.1/lib/rack/handler/
webrick.rb:59
:in `service'
c:/jruby-1.6.7/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
c:/jruby-1.6.7/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
c:/jruby-1.6.7/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
org/jruby/RubyProc.java:270:in `call'
org/jruby/RubyProc.java:224:in `call'
127.0.0.1 - - [07/May/2012:17:05:20 EDT] "GET /csv_file/3764/
e09d5eeee791ac74ff3
25e2163d1712226e466e3.csv HTTP/1.1" 500 120496
http://localhost:4567/ -> /csv_file/3764/
e09d5eeee791ac74ff325e2163d1712226e466e
3.csv


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