OpenX Tips

Great news! Erik Geurts and Matteo Beccati have combined forced, and released a patch for the contract campaign under-delivery bug in the OpenX 2.8.2!

You can find the patch attached to OpenX bug OX-5839.

Last week, long time OpenX consultant (and all round nice guy) Erik Geurts put up a blog post discussing the issues that people seem to be having with OpenX Hosted.

If you’ve had issues with OpenX Hosted, go and let Erik know about them! The Guru has been tracking issues with OpenX Hosted on this site for a while, but unfortunately, most of the forum posts that are tracked promise updates soon, with no resolution forthcoming, and no update on when we can expect fixes.

If everyone with genuine bugs and performance issues on OpenX Hosted lets Erik know, maybe he’ll be able to present the information to OpenX, and hopefully some good will come of it!

Today’s tip comes courtesy of Seagull Systems’ Demian Turner, who quite rightly points out:

“During testing you can set the cache timeout value to some low value like 1 second so that effectively the cache doesn’t get used.”

If you’re debugging banner delivery, or you want to test the results of changing settings like banner capping or companion positioning, then reducing the banner cache value can be a great way of seeing your changes “go live” much faster.

Of course, if you’re doing this on a production system, you may affect delivery performance, so make sure you keep an eye on your system performance monitoring tool!

This week’s tip is something that seems to trip up a lot of new OpenX ad server users. If you can’t seem to link a banner to a zone, this tip is for you.

OpenX will not let you link a banner to a zone unless the banner dimensions match the zone dimensions and the banner type matches the zone type.

Banner types

There are only three different types of banners in OpenX:

• SQL / Webserver / External banners: These are all image or Flash-based banners; they simply have different storage locations¹.
• HTML banners: These are banners based on HTML and/or JavaScript code.
• Text banners: These are banners based on plain text (that is, no HTML markup).

Which type of banner you are using will have an impact on both how the dimensions of the banner are determined, and which zone type you can link the banner to.

Banner dimensions and zone dimensions

SQL and Webserver banners are image or Flash-based banners that you upload into OpenX (which are then stored either in the OpenX database, or are stored on your local web server’s directory). As a result of the fact that OpenX is able to inspect the image or Flash file when it is uploaded, OpenX can automatically determine the banner’s dimensions.

However, External banners cannot be inspected by OpenX; similarly, although HTML banners are stored in the OpenX database, OpenX cannot determine what the dimensions of your HTML/JavaScript code are. As a result, you need to specify the dimensions of all External and HTML banners in OpenX when you create them².

Setting the banner dimensions for an HTML banner.

Zones also have dimensions. Whenever you create a Banner, Button or Rectangle zone, an Interstitial or Floating DHTML zone, a Popup zone or an Email/Newsletter zone, you can select from a set of standard IAB banner dimensions, or you can enter your own dimensions.

Setting the zone dimensions.

In order to link a banner to a zone, the banner dimensions must be exactly the same as the zone dimensions. OpenX will not allow you to link a banner to a zone if the dimensions are not equal. This is a feature of OpenX, which means not only will OpenX ensure that you do not accidentally link, for example, a skyscraper banner into a rectangle zone (which would look rather odd on your site!), but also means that you can set up campaigns containing multiple banners of many different sizes, and then simply link the campaign to zones, and OpenX will figure out which banners to put into which zones.

The exception to the rule of banner and zone dimensions

Text banners and text zones are the exception to the rule, as they have no dimensions. Text banners and zones are used for displaying plain text banners, which are intended to be inserted into normal paragraphs of text on your site. As a result, there is no need for dimensions to be set at either the banner or zone level — the zone and banner will simply be as “high” and as “wide” as the text itself.

Wildcard zones dimensions

Sometimes, you know better than OpenX, and you need to link banners of different dimensions to a single zone. OpenX will let you do this, by using an asterisk as a “wildcard” when setting up a zone with custom dimensions.

You can use the wildcard for the height, the width, or both, depending on your needs.

A zone with "wildcard" width, and fixed height.

Banner type and zone type

To link a banner to a zone, the banner type must be suitable for the zone type (and vice versa). The following table lists all of OpenX’s banner and zone types, according to which types can be linked to each other.

As you can see, text banners and text zones are the odd types out; all other banner/zone combination are fine.

Happy banner/zone linking!

1. That is, SQL banners store the image or Flash-file data in the OpenX database; Webserver banners store the image or Flash data in a file in a directory on your web server; and External banners are where the image or Flash file is stored on some external system, and you simply provide the URL that the file can be loaded from. [↩]
2. OpenX 2.8 now, fortunately, requires these fields be filled in, so that you do not forget. However, older versions of OpenX did not have this requirement — so if you forgot to fill in the banner’s dimensions, if would often take frustrating minutes to figure out why it was not possible to link the banner to the zone. [↩]

The OpenX ad server’s Maintenance Prioritization Engine (MPE) calculates priorities for banners in Contract campaigns. (OpenX’s Contract (Exclusive) and Remnant campaign types have their banners delivered based on relative campaign weights and banner weights.)

However, if you read the fine print about how the MPE works, you may notice that every zone in OpenX has a default zone impression forecast — that is, OpenX assumes that, until it is able to learn what kind of inventory is available in a zone, that it has this number of impressions per hour.

This means that if you create a zone in OpenX, but don’t actually generate its zone tag and put it on your web site (which in turn means that OpenX will never see any requests for banners in the zone), then the OpenX ad server will continue to assume that this zone has the default number of impressions/hour.

While this might not seem like a big deal, consider this: the default is 1,000 impressions/hour. If you link a campaign to just one such “inactive” zone, then the OpenX ad server will think that there are 24,000 more impressions available per day than there really are. That’s a lot of impressions — and the more inactive zones you link your campaigns to, the more of these incorrectly assumed impressions will exist!

This will cause your Contract campaigns to under-deliver.

As a result, you should never link your campaigns or banners to zones that are inactive.