On the Hungarian Wikipedia's recent changes ("friss változtatások") page there is a counter which shows the number of the pages on the candidates for speedy deletion category ("Azonnali törlésre váró lapok"). As you can see on the picture, sometimes it shows a negative number which is obviously wrong. How is it possible that it shows a negative number? Is it possible to fix it?
|Open||None||T18660 Database table cleanup (tracking)|
|Duplicate||None||T18036 Number of category members (PAGESINCATEGORY) is inaccurate for large categories|
|Resolved||TTO||T18765 Write a maintenance script to refresh category member counts|
|Open||None||T170737 Run recountCategories.php on Wikimedia wikis|
|Resolved||None||T169964 Counter of the numbers of the pages on a category shows negative result|
The numbers of pages in categories are occasionally a bit off, mostly because the code updating them is not very reliable in case of race conditions or exceptions happening in the middle of the processing. If they ever get negative, viewing the category page should trigger recalculation of the count (this is actually special-cased). See T18036 for a longer discussion about inaccurate category counts.