Are on-demand users safe from the DST debacle?

Unfortunately, on-demand users may also be affected by today's early switch to daylight saving time — although some are safer than others, it seems. At least they don't have to run around patching servers — thankfully, that's the vendors' problem. But not all vendors can be relied on to do that. And even if they do, their customers still have to cope with the consequences of synchronization mismatches.

There are two factors that determine whether you're going to have either a lot of problems or few to none.

#1 Does your vendor normally do all-in-one updates? An on-demand vendor that runs its software as a single, multi-tenant instance is the safest option of all, because there's very little to go wrong, so long as it has remembered to adjust for DST. That's why Salesforce.com's SVP of product marketing Kendall Collins was bullishly confident about this weekend's change when I spoke to him earlier in the week:

"The time on Salesforce.com is always going to be correct," he told me. Although the company actually runs several separate instances, its policy is always to upgrade them simultaneously. "We make that change and it's instantly effective across all our customers." Coincidentally, Salesforce.com was scheduled to implement a major upgrade across all its servers on Friday, although not for the DST update, which has already been done.

Problems come if a vendor runs multiple instances on multiple servers and doesn't make sure of ugrading them all at the same time. Surprisingly (and damningly, for a company that wants to show how serious a player it is in the on-demand market), Google falls into this category, as Spanning Partners' Charlie Wood reported on his blog last week (with my emphasis added):

"Even the great and mighty Google Calendar suffers from a DST bug, and a nasty one since it's sporadic. If you use the Google Calendar API to create a recurring event that begins between March 11 and April 14 of this year (the new and old DST boundaries, respectively), it will be off by an hour—but only sometimes. Apparently some of their servers have been upgraded to use the new timezone definitions and some haven't. Google is aware of the problem but hasn't made a big deal about it, and has yet to fix it."

Charlie notes that his company's Spanning Sync application, which synchronizes iCal with Google Calendar, may be an unusually heavy user of the gCal API, but that already means there are 18,000 users potentially affected by this bug. Google's response suggests simply waiting until it clears up:

Our apologies for this bug. It will be resolved, but probably not before daylight savings begins on 3/11.

#2 Does the application synchronize with applications running elsewhere? The big headache arising from this year's early start to DST comes because we live in such a connected world. Fifteen years ago, the problem would simply have been a matter of patching individual computers and co-ordinating that work within corporate networks. Today, that's just the start. The bigger problem comes from co-ordinating all the synchronization mismatches that arise from the fact that we're all connected, but none of us have done our DST updates at the same time.

So for example, if the DST change has moved the times of appointments in your Outlook calendar and the meeting organizer (it may be you but often it's someone else) has not corrected them, those incorrect times will get imported into Salesforce.com when you synchronize between the two. (For advice on making sure your Outlook appointments are correct, see The lazy person’s guide to adjusting your PC for daylight saving).

More worrying is the potential for transferring incorrect times when moving data across an API link, for example invoice or delivery times on sales orders. Automatically scheduled events, such as daily batch updates, may fail because of timeouts if they are attempted an hour early or late.

Fortunately, many of these problems can be overcome by simply being vigilant over the next few days and not taking information for granted — especially date-stamped information — without first verifying that it has been adjusted for DST. We should learn the lesson of the next few days and come to terms with how interdependent our modern web-connected world has made us.