And from Deutsche Welle. They talk about security plans. The best security plan is to forcibly evict all Muslims back to where they came from.

quote
"The most immediate question pertained to concrete safety plans. The Berlin Christmas market attack of December 2016, when 13 people were killed by a Tunisian asylum-seeker who drove a truck into a crowd, resulted in two parliamentary inquiries and immediate safety upgrades: Heavy concrete blocks, road blocks, and increased police presences were introduced at markets throughout Germany and Austria.
But it appears that the markets, which attract thousands of people and appear in almost every available space in German cities in the 5-6 weeks leading up to Christmas, can never be totally secured from vehicles — partly because emergency vehicles also need to be able to access the market, and because there need to be multiple emergency exits for people to escape.
"The places that the perpetrator used were the emergency access routes and the emergency exits," Ronni Krug, a Magdeburg city official, told reporters on Saturday, before referring to the Duisburg Love Parade incident of 2010, when 21 were killed in a crush partly because there weren't enough emergency exits. He added that the security plan at all of Magdeburg's Christmas markets had been "created according to the best knowledge," and that security plans for such markets were continually updated."
https://www.dw.com/en/security-questions-over-christmas-market-attack-in-magdeburg/a-71138203