vb.org Archive - View Single Post - When to create indexes on custom tables?

So for instance, i have the query shown in query.gif (attached) which I am trying to optimize. I ran explain on it (also attached as explain.gif) and it's telling me that I need to create an index on table 1`c` correct?

I created an index on table scst_fb for fbid and when i run the query, it's still saying filesort in the extra column for explain. Shouldn't it be using the index now?

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X vBulletin 3.8.12 by vBS Debug Information

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X vBulletin 3.8.12 by vBS Debug Information
Page Generation 0.01202 seconds Memory Usage 1,778KB Queries Executed 12 (?)
More Information
Template Usage: (1)SHOWTHREAD_SHOWPOST (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_box (1)post_thanks_button (1)post_thanks_javascript (1)post_thanks_navbar_search (1)post_thanks_postbit_info (1)postbit (2)postbit_attachment (1)postbit_onlinestatus (1)postbit_wrapper (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit reputationlevel showthread	Included Files: ./showpost.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/functions_bigthree.php ./includes/class_postbit.php ./includes/class_bbcode.php ./includes/functions_reputation.php ./includes/functions_post_thanks.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_postinfo_query fetch_postinfo fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete showpost_start bbcode_fetch_tags bbcode_create postbit_factory showpost_post postbit_display_start post_thanks_function_post_thanks_off_start post_thanks_function_post_thanks_off_end post_thanks_function_fetch_thanks_start post_thanks_function_fetch_thanks_end post_thanks_function_thanked_already_start post_thanks_function_thanked_already_end fetch_musername postbit_imicons bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete postbit_attachment postbit_display_complete post_thanks_function_can_thank_this_post_start showpost_complete
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