मेरे पास सामग्री की हजारों पंक्तियों (लगभग 3 मिलियन) के साथ एक जूमला टेबल है। मुझे टेबल क्वेरी पूछते समय जितनी जल्दी संभव हो सके डेटाबेस क्वेरी को पुनः लिखने में कुछ परेशानी हो रही है।कॉम्प्लेक्स माईएसQL क्वेरी अभी भी फाइलोर्ट का उपयोग कर रहा है हालांकि इंडेक्स मौजूद हैं
यहाँ मेरी पूरी क्वेरी है:
SELECT cc.title AS category, a.id, a.title, a.alias, a.title_alias, a.introtext, a.fulltext, a.sectionid, a.state, a.catid, a.created, a.created_by, a.created_by_alias, a.modified, a.modified_by, a.checked_out, a.checked_out_time, a.publish_up, a.publish_down, a.attribs, a.hits, a.images, a.urls, a.ordering, a.metakey, a.metadesc, a.access, CASE WHEN CHAR_LENGTH(a.alias) THEN CONCAT_WS(":", a.id, a.alias) ELSE a.id END AS slug, CASE WHEN CHAR_LENGTH(cc.alias) THEN CONCAT_WS(":", cc.id, cc.alias) ELSE cc.id END AS catslug, CHAR_LENGTH(a.`fulltext`) AS readmore, u.name AS author, u.usertype, g.name AS groups, u.email AS author_email
FROM j15_content AS a
LEFT JOIN j15_categories AS cc
ON a.catid = cc.id
LEFT JOIN j15_users AS u
ON u.id = a.created_by
LEFT JOIN j15_groups AS g
ON a.access = g.id
WHERE 1
AND a.access <= 0
AND a.catid = 108
AND a.state = 1
AND (publish_up = '0000-00-00 00:00:00' OR publish_up <= '2012-02-08 00:16:26')
AND (publish_down = '0000-00-00 00:00:00' OR publish_down >= '2012-02-08 00:16:26')
ORDER BY a.title, a.created DESC
LIMIT 0, 10
यहाँ से उत्पादन होता है एक व्याख्या:
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-----------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-----------------------------+
| 1 | SIMPLE | a | ref | idx_access,idx_state,idx_catid,idx_access_state_catid | idx_catid | 4 | const | 3108187 | Using where; Using filesort |
| 1 | SIMPLE | cc | const | PRIMARY | PRIMARY | 4 | const | 1 | |
| 1 | SIMPLE | u | eq_ref | PRIMARY | PRIMARY | 4 | database.a.created_by | 1 | |
| 1 | SIMPLE | g | eq_ref | PRIMARY | PRIMARY | 1 | database.a.access | 1 | |
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-----------------------------+
और दिखाने के लिए अनुक्रमित क्या मौजूद हैं, शो सूचकांक j15_content से:
+-------------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-------------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| j15_content | 0 | PRIMARY | 1 | id | A | 3228356 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_section | 1 | sectionid | A | 2 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_access | 1 | access | A | 1 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_checkout | 1 | checked_out | A | 2 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_state | 1 | state | A | 2 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_catid | 1 | catid | A | 6 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_createdby | 1 | created_by | A | 1 | NULL | NULL | | BTREE | |
| j15_content | 1 | title | 1 | title | A | 201772 | 4 | NULL | | BTREE | |
| j15_content | 1 | idx_access_state_catid | 1 | access | A | 1 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_access_state_catid | 2 | state | A | 2 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_access_state_catid | 3 | catid | A | 7 | NULL | NULL | | BTREE | |
| j15_content | 1 | idx_title_created | 1 | title | A | 3228356 | 8 | NULL | | BTREE | |
| j15_content | 1 | idx_title_created | 2 | created | A | 3228356 | NULL | NULL | | BTREE | |
+-------------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
जैसा कि आप देख सकते हैं कि डेटाबेस से डेटा के कुछ टुकड़े किए जा रहे हैं। अब मैंने क्वेरी को सरल बनाकर परीक्षण किया है कि असली मुद्दा ऑर्डर द्वारा ऑर्डर के साथ है। परिणाम आदेश देने के बिना, क्वेरी काफी संवेदनशील है, यहाँ एक स्पष्टीकरण है:
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-------------+
| 1 | SIMPLE | a | ref | idx_access,idx_state,idx_catid,idx_access_state_catid | idx_catid | 4 | const | 3108187 | Using where |
| 1 | SIMPLE | cc | const | PRIMARY | PRIMARY | 4 | const | 1 | |
| 1 | SIMPLE | u | eq_ref | PRIMARY | PRIMARY | 4 | database.a.created_by | 1 | |
| 1 | SIMPLE | g | eq_ref | PRIMARY | PRIMARY | 1 | database.a.access | 1 | |
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-------------+
आप इसे घातक filesort कि सर्वर की मौत हो गई है देख सकते हैं। इस कई पंक्तियों के साथ, मैं इंडेक्स के माध्यम से सब कुछ अनुकूलित करने के लिए अपनी पूरी कोशिश कर रहा हूं लेकिन कुछ अभी भी इसके साथ सही नहीं है। कोई भी इनपुट बहुत प्रंशसनीय होगा।
कोई लाभ नहीं हुआ बल सूचकांक का उपयोग कर की कोशिश की:
explain SELECT cc.title AS category, a.id, a.title, a.alias, a.title_alias, a.introtext, a.fulltext, a.sectionid, a.state, a.catid, a.created, a.created_by, a.created_by_alias, a.modified, a.modified_by, a.checked_out, a.checked_out_time, a.publish_up, a.publish_down, a.attribs, a.hits, a.images, a.urls, a.ordering, a.metakey, a.metadesc, a.access, CASE WHEN CHAR_LENGTH(a.alias) THEN CONCAT_WS(":", a.id, a.alias) ELSE a.id END AS slug, CASE WHEN CHAR_LENGTH(cc.alias) THEN CONCAT_WS(":", cc.id, cc.alias) ELSE cc.id END AS catslug, CHAR_LENGTH(a.`fulltext`) AS readmore, u.name AS author, u.usertype, g.name AS groups, u.email AS author_email
-> FROM bak_content AS a
-> FORCE INDEX (idx_title_created)
-> LEFT JOIN bak_categories AS cc
-> ON a.catid = cc.id
-> LEFT JOIN bak_users AS u
-> ON u.id = a.created_by
-> LEFT JOIN bak_groups AS g
-> ON a.access = g.id
-> WHERE 1
-> AND a.access <= 0
-> AND a.catid = 108
-> AND a.state = 1
-> AND (publish_up = '0000-00-00 00:00:00' OR publish_up <= '2012-02-08
-> AND (publish_down = '0000-00-00 00:00:00' OR publish_down >= '2012-0
-> ORDER BY a.title, a.created DESC
-> LIMIT 0, 10;
का उत्पादन:
+----+-------------+-------+--------+---------------+---------+---------+-------
| id | select_type | table | type | possible_keys | key | key_len | ref
+----+-------------+-------+--------+---------------+---------+---------+-------
| 1 | SIMPLE | a | ALL | NULL | NULL | NULL | NULL
| 1 | SIMPLE | cc | const | PRIMARY | PRIMARY | 4 | const
| 1 | SIMPLE | u | eq_ref | PRIMARY | PRIMARY | 4 | database
| 1 | SIMPLE | g | eq_ref | PRIMARY | PRIMARY | 1 | database
+----+-------------+-------+--------+---------------+---------+---------+-------
मैं इन इंडेक्स को एक कोशिश करूंगा: '(राज्य, कैटिड, एक्सेस)' या '(राज्य, कैटिड, publ_up)' या '(राज्य, कैटिड, publ_down)' –
यदि आप 'LIMIT' का उपयोग नहीं करते हैं कई पंक्तियां वापस आती हैं? –
आप 'idx_title_created' अनुक्रमणिका के उपयोग को मजबूर करने का भी प्रयास कर सकते हैं। –