Fix missing index column in /filter
I found something missing in one line of the final code (maybe lost during one of the multiple merges of the main branch and subsequent conflict resolutions).

CC: @severo @lhoestq 
Fix missing index column in /filter: I found something missing in one line of the final code (maybe lost during one of the multiple merges of the main branch and subsequent conflict resolutions).

CC: @severo @lhoestq 