function handle_notice(options) {
  var default_options = $H({show_notice: false, show_ignore: false})
  options = default_options.merge($H(options))
  ...
}

The above sets up a hash of default options, then merges or updates the default_options with the options hash passed to the function. This allows me to use any combination of arguments, or pass none to use the default.

module MigrationHelper
  def index_exists?(table, lookup)
    lookup = Hash[:columns, Array(lookup)] unless lookup.is_a?(Hash)
    lookup.symbolize_keys!
    lookup.each{|key,value|lookup[key]=(value.is_a?(Array))?(value.collect{|v|v.to_s}):(value.to_s)}
    indexes(table).collect(&lookup.keys.first).include?(lookup.values.first)
  end
 
  def change_column_nulls(table_name, nullable, *column_names)
    column_names.each do |column_name|
      table_columns = columns(table_name) 
      column_def = table_columns.select{|c|c.name == column_name.to_s}
      raise "Unknown column name #{column_name} for #{table_name}\nAvailable columns: #{table_columns.collect(&:name).to_sentence}" if column_def.empty?
      change_column table_name, column_name, column_def.first.type, :null => nullable
    end
  end
 
  def change_column_defaults(table_name, default, *column_names)
    column_names.each do |column_name|
      change_column_default table_name, column_name, default
    end
  end
end

I fond it necessary to have the index_exists? method mainly for my development purposes. When I’m optimizing tables by doing complex indexes, I often do them right on the DB first before throwing them into a migration. By having this check I can easily skip over it if it already exists. It takes the same options as add_index. You can pass table and column names, or just table and index name. Here are some usage examples:

add_index :table, :column unless index_exists?(:table, :column)
add_index :table, [:column1, :column2] unless index_exists?(:table, [:column1, :column2])
add_index :table, [:column1, :column2, :column3], :name => "some_index_name" unless index_exists?(:table, :name => "some_index_name")

The method change_column_nulls is used to mass change the NULL allowed columns for a given table. Really not much to it, but saves a lot of code over doing change_table or change_column. Here is the usage:

change_column_nulls :table, false, :column1, :column2

And lastly change_column_defaults is just a wrapper around change_column_default for mass assignment. Usage is the same as change_column_nulls passing the default values as the second argument. I thought about combining the two, but it didn’t offer very much savings.

These were tested using MySql 5. I’m not sure about the compatibility with other servers.

Please see Solr Java-Based Replication for setup overview.  I will cover specific modification I had to make compared to what is in their documentation.  In my solrconfig.xml on my Master server, I have the following:

<requestHandler name="/replication" class="solr.ReplicationHandler" >
      <lst name="master">
          <!--Replicate on 'startup' and 'commit'. 'optimize' is also a valid value for replicateAfter. -->
          <str name="replicateAfter">startup</str>
          <str name="replicateAfter">commit</str>
      </lst>
  </requestHandler>

Then on the slave servers, I have:

<requestHandler name="/replication" class="solr.ReplicationHandler" >
      <lst name="slave">
          <!--fully qualified url for the replication handler of master . It is possible to pass on this as a request param for the fetchindex command-->
          <str name="masterUrl">http://{solr_host}:{solr_port}/solr/${solr.core.name}/replication</str>
          <!--Interval in which the slave should poll master .Format is HH:mm:ss . If this is absent slave does not poll automatically. 
           But a fetchindex can be triggered from the admin or the http API -->
          <str name="pollInterval">00:00:30</str>
          <str name="httpReadTimeout">10000</str>-->
       </lst>
  </requestHandler>

Substitute {solr_host} and {solr_port} with your specific settings. IMPORTANT: Note the ${solr.core.name} variable.  This makes it so the slaves will poll from the correct MultiCore path on the Master server.

Upgrading was quite easy.  See http://wiki.apache.org/solr/Solr1.4 for upgrading notes.  What I will focus on are the details of using and automating the MultiCore functionality.  To enable the dynamic SolrCore functionality, you just need to put the following XML in solr.xml inside your solr_home directory.

<solr persistent="true" sharedLib="lib">
 <cores adminPath="/admin/cores">
 </cores>
</solr>

Don’t worry about creating any cores at this time.  The next thing I did was create a directory called “default” in my solr_home directory to store all of my shared configs for each core.  I then copied the conf/ directory from my solr_home into the newly created default dir.

The final step is to create the cores needed.  You can automate this by posting the following request and checking the XML response, or by just pasting this into your browser.

http://{host}:{port}/{solr_home}/admin/cores?action=CREATE&name={core_name}&instanceDir=default&dataDir={/full/path/to/solr/home}/{core_name}

Here is how you automate the request using xml-simple and ruby

#set the url string equal to the above command
response = Net::HTTP.get_response(URI.parse(url)).body
xml = XmlSimple.xml_in(response, {'VarAttr' => 'name', 'ContentKey' => '-content', 'KeyAttr' => 'name'})
raise "Failed to create solr core" if xml["lst"]["responseHeader"]["int"]["status"].to_i != 0

Master Solr server after upgrade to 1.4 and multi-core

Solr slave server after upgrade to 1.4 and multi-core

Since I was already jailbroken, I simply built the custom IPSW, and clicked Option+Restore in iTunes. Everything went as expected, and I finally have a stable phone again.

I’ve been jailbreaking my phone since I first got it over a year ago, and I’m so glad to see the process getting easier and smoother every time. Big thanks to the iPhone Dev Team and all their hard work.

Here are the steps I took in case you are already jailbroken and just want the bug fixes and 3.1 update.

Requirements
• Mac OS X
• iTunes 9.0.1
• Already jailbroken iPhone 3G on 3.0 firmware
• Backups!

Steps
• Check for updates in iTunes
• Choose to download only for the update
• Download PwnageTool 3.1.4 Torrent Mirror
• Launch PwnageTool and go walk through the steps to create your custom IPSW
• Answer Yes to already jailbroken and exit the app when prompted
• Launch iTunes and hold the Option key and click Restore
• Select your custom IPSW file (probably on your destop)
• Enjoy your new 3.1.2 jailbreak

SELECT AVG(column1) AS column1, AVG(column2) AS column2 FROM table1 t1
JOIN table2 t2 ON t2.id = t1.tabel2_id
GROUP BY YEAR(t2.datetime_field)

Rather than using this sql in ActiveRecord via find_by_sql, I figured I’d make it pretty and use the built in find method. Here is what I came up with:

Table1.find(:all, :select => 't2_id, AVG(column1) as column1, AVG(column2) as column2', :joins => :t2, :group => 'YEAR(t2.datetime_field)')

The :select option allows you to define the attributes you want returned with the AR object. I’m using MySQL to do the averaging of the data via the AVG function. I would normally use the :include option for joins, but I couldn’t get it to work with this query, so the :joins option seemed to work well by passing it the association definition from the model. The :group option simply works the same as the SQL group by. Just pass it a sql fragment, in my case just the year field portion of the datetime field.

map.route_name 'controller_name/action_name/:foo_id', :controller => 'controller_name', :action => 'action_name'

I had to change the redirect_to in my RJS file from this:

page.redirect_to page_recrawl_path(:foo_id => @foo_id, :bar_id => @bar_id, :bang => true)

To this:

page.redirect_to page_recrawl_path(@foo_id, {:bar_id => @bar_id, :bang => true})

Apps

• Cycorder: Yes
• OpenSSH: Yes
• SBS Settings: Yes
• Icy: Yes
• Cydia: Stability issues
• PdaNet: Yes, but possible stability issues
• Winterboard: Mostly, some themes weren’t stable
• Pwnplayer: no
• Snapture: no
• NES: no

Overall the new 3.0 features were well worth upgrading. The only app I will really miss is Pwn player and I hope there will be a similar replacement (it’s no longer maintained).  As for the other apps, I’m sure they’ll be getting updates soon.  Please let me know what apps you have working.

user.roles.verify_active_connections!

This will make sure users, user_roles, and roles all have valid connections. This error occurred using rails 2.0.1. It may be fixed in newer versions of ActiveRecord.