#	exclusive	inclusive	rows x	rows	loops	node
1.	13.546	80.616	↑ 1.0	2049	1	→ Merge Right Join (cost=2254.55..3127.60 rows=2056 width=588) (actual time=46.884..80.616 rows=2049 loops=1) Merge Cond: (ctx.instanceid = c.id)
2.	17.251	17.251	↑ 1.0	3326	1	→ Index Scan using mdl_cont_ins_ix on mdl_context ctx (cost=0.00..18582.99 rows=3449 width=48) (actual time=0.028..17.251 rows=3326 loops=1) Filter: (contextlevel = 50)
3.	11.714	49.819	↑ 1.0	2049	1	→ Sort (cost=2254.55..2259.69 rows=2056 width=540) (actual time=46.814..49.819 rows=2049 loops=1) Sort Key: c.id Sort Method: quicksort Memory: 1331kB
4.	15.057	38.105	↑ 1.0	2049	1	→ Nested Loop IN Join (cost=0.00..2141.41 rows=2056 width=540) (actual time=0.026..38.105 rows=2049 loops=1)
5.	6.368	6.368	↑ 4.0	3336	1	→ Seq Scan on mdl_course c (cost=0.00..838.39 rows=13339 width=540) (actual time=0.006..6.368 rows=3336 loops=1)
6.	16.680	16.680	↑ 17.0	1	3336	→ Index Scan using mdl_even_cou_ix on mdl_event (cost=0.00..1.42 rows=17 width=8) (actual time=0.005..0.005 rows=1 loops=3336) Index Cond: (mdl_event.courseid = c.id)

 Merge Right Join  (cost=2254.55..3127.60 rows=2056 width=588) (actual time=46.884..80.616 rows=2049 loops=1)
   Merge Cond: (ctx.instanceid = c.id)
   ->  Index Scan using mdl_cont_ins_ix on mdl_context ctx  (cost=0.00..18582.99 rows=3449 width=48) (actual time=0.028..17.251 rows=3326 loops=1)
         Filter: (contextlevel = 50)
   ->  Sort  (cost=2254.55..2259.69 rows=2056 width=540) (actual time=46.814..49.819 rows=2049 loops=1)
         Sort Key: c.id
         Sort Method:  quicksort  Memory: 1331kB
         ->  Nested Loop IN Join  (cost=0.00..2141.41 rows=2056 width=540) (actual time=0.026..38.105 rows=2049 loops=1)
               ->  Seq Scan on mdl_course c  (cost=0.00..838.39 rows=13339 width=540) (actual time=0.006..6.368 rows=3336 loops=1)
               ->  Index Scan using mdl_even_cou_ix on mdl_event  (cost=0.00..1.42 rows=17 width=8) (actual time=0.005..0.005 rows=1 loops=3336)
                     Index Cond: (mdl_event.courseid = c.id)
 Total runtime: 84.229 ms

Per node type stats

node type	count	sum of times	% of query
Index Scan	2	33.931 ms	42.1 %
Merge Right Join	1	13.546 ms	16.8 %
Nested Loop IN Join	1	15.057 ms	18.7 %
Seq Scan	1	6.368 ms	7.9 %
Sort	1	11.714 ms	14.5 %

Per table stats

Table name	Scan count	Total time	% of query
scan type	count	sum of times	% of table
mdl_context	1	17.251 ms	21.4 %
Index Scan	1	17.251 ms	100.0 %
mdl_course	1	6.368 ms	7.9 %
Seq Scan	1	6.368 ms	100.0 %
mdl_event	1	16.680 ms	20.7 %
Index Scan	1	16.680 ms	100.0 %

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