add instructions to the test_all_hashes test

test/test_all_hashes.rb

@@ -1,4 +1,13 @@
-# shows the effect of using .all_hashes instead of looping on each hash 
+# To run first execute:
+=begin
+create database local_test_db;
+use local_test_db;
+CREATE TABLE test_table (
+         c1 INT, 
+         c2 VARCHAR(20)
+     );
+=end
+# This script shows the effect of using .all_hashes instead of looping on each hash 
 # run it by substiting in a 'long' [many row] query for the query variable and toggling use_all_hashes here at the top
 # note that we load all the rows first, then run .all_hashes on the result [to see more easily the effect of all hashes]
 # on my machine and a 200_000 row table, it took 3.38s versus 3.65s for the old .each_hash way [note also that .each_hash is 
@@ -13,16 +22,22 @@ $start = Time.now
 
 $connections = []
 $count.times do  
-  $connections << Mysql.real_connect('localhost','root', '', 'local_leadgen_dev')
+  $connections << Mysql.real_connect('localhost','root', '', 'local_test_db')
 end
 
+puts 'initing db'
+# init the DB
+conn = Mysql.real_connect('localhost', 'root', '', 'local_test_db')
+conn.query("delete from test_table")
+200_000.times {conn.query(" insert into test_table (c1, c2) values (3, 'ABCDEFG')")}
 puts 'connection pool ready'
 
+
 $threads = []
 $count.times do |i|
   $threads << Thread.new do
 
-    query = "select * from campus_zips"
+    query = "select * from test_table"
     puts "sending query on connection #{i}"
     conn = $connections[i]
     result = conn.async_query(query)