How Search Works in Postbox
Before we dive in, here's an overview of how searching works in Postbox.
Postbox's search index is similar to an index that you might find at the back of a book, and it can be much faster to find things using an index than scanning the book itself.
In order for messages to be searchable, Postbox has first "see" the messages, then it adds what it sees to the search index. When you perform a search, Postbox searches the index for your messages and displays the results. This is much faster than searching through the mail databases themselves.
Messages are received by most email clients in two steps:
- First, the message headers are downloaded, and they contain information used to populate the message list such as subject, sender, and date.
- Second, when a message is selected the message bodies (or contents) are then downloaded.
Similarly, Postbox indexes messages using the same two-step process. When Postbox downloads message headers, they are automatically indexed as they come in. Once a message is selected, its contents are downloaded and Postbox adds this information to the index. (Note that Postbox only indexes the non-quoted parts of a message, as it is assumed that the quoted parts will be indexed as they exist in other messages.)
However, Postbox cannot index messages it has not yet seen, so there are a variety of settings that you can adjust to make indexing work more efficiently for you.
How to Index Email Messages for Search
As mentioned, Postbox will index message headers as they come into the app. But note that message headers will not be downloaded until a folder is actually selected, and message bodies will not be downloaded until a message is actually selected.
To index all messages across all folders, navigate to the Tools menu and select Indexing > Index All Folders. You can continue working while Postbox indexes in the background.
Additionally, Postbox provides new settings that will allow you to fine-tune how messages are indexed.
To have Postbox automatically download all headers across all folders when it checks for messages, navigate to Preferences | Options > Advanced > General and select the option for "Download all messages headers."
To have Postbox automatically download all message bodies when a folder is selected, navigate to Preferences | Options > Advanced > General and select the option for "Download all messages bodies." Note that this setting only works for folders that have been set to download offline.
When both of these settings are selected, Postbox will automatically download and index all headers and message bodies across all folders marked for offline. So be sure to set IMAP Limiting to a value other than "No Limit," as otherwise you might download and index messages you no longer need access to.
When Postbox detects that your computer is idle, it will automatically walk through your folder structure, download message headers and bodies, then index them. The amount of idle time is now adjustable in Preferences | Options > Advanced > General > Index on idle after 180 seconds. If you wish for Postbox to more aggressively index, set this preference to a lower number. If you wish for Postbox to wait longer before indexing, set this preference to a higher number.
Note that the indexing process does consume a fair amount of CPU and hard drive reads/writes. So if you are in an important meeting, you may wish to set the idle index number to a higher number to prevent Postbox from indexing.
By default, Postbox only indexes your email messages and RSS articles. However, you can enable the indexing of newsgroups if you would like to have these messages appear in the search. Just go to:
Mac: Postbox > Preferences > Accounts > [Newsgroup] > Local Storage
Windows: Tools > Options > Accounts > [Newsgroup] > Local Storage
and check the option to Index message bodies.
Indexing RSS Feeds
Postbox indexes RSS articles by default. If you would not like to see articles when searching for messages in Postbox, go to:
Mac: Postbox > Preferences > Accounts > [RSS Account]
Windows: Tools > Options > Accounts > [RSS Account]
and uncheck the option to Index message bodies.