I have a drupal site that has been running for about 1 year. there are about 1000 members in the users table

recently I have noticed something very strange the Users uid field is no longer inrementing sequentially.

It now jumps up in the 10s, for example, my last 8 users, the uids went from 7999 to 8068, 8094, 8350, 8416, 8458, 8534, 8566.

So sometimes it is jumping 100s at a time.

How can I work out what might be causing this, and should I be worried?

  • Can users create their own accounts? Do you have a CAPTCHA preventing automated user registration spam? Mar 10, 2014 at 23:01
  • Seems to me it's nothing to do with 10's but just random jumps.
    – rooby
    Mar 10, 2014 at 23:15
  • Are you definitely using drupal 6 as per the tags on this post or are you on drupal 7?
    – rooby
    Mar 10, 2014 at 23:30
  • Yes, system is built on Drupal 6 and you're right, its not in 10s exactly, I just meant that it does not increment in single iterations. Users can create their own accounts, but there is a table of application requests that records the details of a Users account creation and there are no corresponding entries for the missing uids. It should not be possible to create a user account without it being registered in the requests table. Mar 11, 2014 at 9:10
  • Here's your answer drupal.stackexchange.com/a/42739/7641. I guess that makes this question a duplicate. Mar 14, 2014 at 0:50

1 Answer 1


If it is exactly 10 then it might have to do with MySQL's Auto Increment value https://stackoverflow.com/questions/1686327/change-the-step-auto-increment-fields-increment-by

drupal.org currently uses this feature for master slave replication. Right now all users and nodes being created have a odd value. If you look further back this value was EVEN at one point.

  • ITs not in even amounts of 10 as can be seen from the sequence I posted in the question Mar 14, 2014 at 8:57

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