fix(db): Do not JOIN recipients when fetching the latest messages #10930
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As discussed with @st3iny, there seems no reason to JOIN because we don't filter on the data.
MariaDB analyze
Before
{ "query_optimization": { "r_total_time_ms": 0.295886183 }, "query_block": { "select_id": 1, "cost": 17.2639218, "r_loops": 1, "r_total_time_ms": 7.380777476, "nested_loop": [ { "read_sorted_file": { "r_rows": 300, "filesort": { "sort_key": "m.sent_at desc", "r_loops": 1, "r_total_time_ms": 5.414184066, "r_used_priority_queue": false, "r_output_rows": 4544, "r_buffer_size": "1817Kb", "r_sort_mode": "sort_key,rowid", "table": { "table_name": "m", "access_type": "range", "possible_keys": [ "PRIMARY", "mail_messages_mb_id_uid_uidx", "mail_messages_id_flags", "mail_messages_id_flags2", "mail_msg_thrd_root_snt_idx" ], "key": "mail_messages_mb_id_uid_uidx", "key_length": "4", "used_key_parts": ["mailbox_id"], "loops": 1, "r_loops": 1, "rows": 4560, "r_index_rows": 4544, "r_rows": 4544, "cost": 1.0139296, "r_table_time_ms": 5.357798992, "r_other_time_ms": 0.370584295, "r_engine_stats": { "pages_accessed": 9741 }, "filtered": 100, "r_total_filtered": 100, "index_condition": "m.mailbox_id in (696,708,703,706,705,712,707,695,711,702,700,697,693,704,701,698,692)", "r_icp_filtered": 100, "r_filtered": 100 } } } }, { "table": { "table_name": "r", "access_type": "ref", "possible_keys": ["mail_recipient_msg_id_idx", "20250325_test_mr_type"], "key": "mail_recipient_msg_id_idx", "key_length": "5", "used_key_parts": ["message_id"], "ref": ["nextcloud.m.id"], "rowid_filter": { "range": { "key": "20250325_test_mr_type", "used_key_parts": ["type"] }, "rows": 9598, "selectivity_pct": 61.68776914, "r_rows": 4768, "r_lookups": 984, "r_selectivity_pct": 30.48780488, "r_buffer_size": 4768, "r_filling_time_ms": 0.875788622 }, "loops": 4560, "r_loops": 300, "rows": 3, "r_index_rows": 3.28, "r_rows": 1, "cost": 16.2499922, "r_table_time_ms": 1.459849695, "r_other_time_ms": 0.054745228, "r_engine_stats": { "pages_accessed": 1216 }, "filtered": 61.68777084, "r_total_filtered": 30.48780488, "index_condition": "m.`id` = r.message_id", "r_icp_filtered": 100, "attached_condition": "r.`type` = 0", "r_filtered": 100 } } ] } }After
{ "query_optimization": { "r_total_time_ms": 0.516227237 }, "query_block": { "select_id": 1, "cost": 1.0139296, "r_loops": 1, "r_total_time_ms": 6.236020586, "nested_loop": [ { "read_sorted_file": { "r_rows": 300, "filesort": { "sort_key": "m.sent_at desc", "r_loops": 1, "r_total_time_ms": 5.889989475, "r_limit": 300, "r_used_priority_queue": true, "r_output_rows": 301, "r_sort_mode": "sort_key,rowid", "table": { "table_name": "m", "access_type": "range", "possible_keys": [ "mail_messages_mb_id_uid_uidx", "mail_messages_id_flags", "mail_messages_id_flags2", "mail_msg_thrd_root_snt_idx" ], "key": "mail_messages_mb_id_uid_uidx", "key_length": "4", "used_key_parts": ["mailbox_id"], "loops": 1, "r_loops": 1, "rows": 4560, "r_index_rows": 4544, "r_rows": 4544, "cost": 1.0139296, "r_table_time_ms": 5.489310666, "r_other_time_ms": 0.715012756, "r_engine_stats": { "pages_accessed": 9741 }, "filtered": 100, "r_total_filtered": 6.624119718, "index_condition": "m.mailbox_id in (696,708,703,706,705,712,707,695,711,702,700,697,693,704,701,698,692)", "r_icp_filtered": 100, "r_filtered": 100 } } } } ] } }