我在许多主题相同的wordpress网站上工作。 world.smart-shopping.com（DB = 54.9 Mo）和mes-bons-plans.be（DB = 14.6 Mo）。每个站点上的相同请求不会花费相同的时间。对于.be，大约是0.2秒，对于世界，大约是5秒。
这是请求（针对世界）：
SELECT SQL_CALC_FOUND_ROWS wpsmcp_posts.ID
FROM wpsmcp_posts INNER
JOIN wpsmcp_postmeta ON ( wpsmcp_posts.ID = wpsmcp_postmeta.post_id )
INNER JOIN wpsmcp_postmeta AS mt1 ON ( wpsmcp_posts.ID = mt1.post_id )
WHERE 1=1 AND ( wpsmcp_postmeta.meta_key = '_wpc_expires' AND ( (
mt1.meta_key = '_wpc_expires' AND CAST(mt1.meta_value AS SIGNED)
BETWEEN '1546946077' AND '1547205277' ) ) ) AND wpsmcp_posts.post_type
= 'coupon' AND (wpsmcp_posts.post_status = 'publish' OR wpsmcp_posts.post_status = 'private') GROUP BY wpsmcp_posts.ID ORDER
BY wpsmcp_postmeta.meta_value+0 ASC LIMIT 0, 6
我运行了sql解释程序，但是我在mysql中的级别太低，无法理解所有内容。
对于.be：
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "38629.34"
},
"ordering_operation": {
"using_filesort": true,
"grouping_operation": {
"using_temporary_table": true,
"using_filesort": false,
"nested_loop": [
{
"table": {
"table_name": "wpsmbe_postmeta",
"access_type": "ref",
"possible_keys": [
"post_id",
"meta_key"
],
"key": "meta_key",
"used_key_parts": [
"meta_key"
],
"key_length": "767",
"ref": [
"const"
],
"rows_examined_per_scan": 10433,
"rows_produced_per_join": 10433,
"filtered": "100.00",
"cost_info": {
"read_cost": "6075.00",
"eval_cost": "2086.60",
"prefix_cost": "8161.60",
"data_read_per_join": "10M"
},
"used_columns": [
"post_id",
"meta_key",
"meta_value"
],
"attached_condition": "((`*_wpsmbe`.`wpsmbe_postmeta`.`meta_key` <=> '_wpc_expires') and (`*_wpsmbe`.`wpsmbe_postmeta`.`meta_key` = '_wpc_expires'))"
}
},
{
"table": {
"table_name": "wpsmbe_posts",
"access_type": "eq_ref",
"possible_keys": [
"PRIMARY",
"type_status_date"
],
"key": "PRIMARY",
"used_key_parts": [
"ID"
],
"key_length": "8",
"ref": [
"*_wpsmbe.wpsmbe_postmeta.post_id"
],
"rows_examined_per_scan": 1,
"rows_produced_per_join": 1150,
"filtered": "11.03",
"cost_info": {
"read_cost": "10433.00",
"eval_cost": "230.10",
"prefix_cost": "20681.20",
"data_read_per_join": "4M"
},
"used_columns": [
"ID",
"post_status",
"post_type"
],
"attached_condition": "((`*_wpsmbe`.`wpsmbe_posts`.`post_type` = 'coupon') and (`*_wpsmbe`.`wpsmbe_posts`.`post_status` = 'publish'))"
}
},
{
"table": {
"table_name": "mt1",
"access_type": "ref",
"possible_keys": [
"post_id",
"meta_key"
],
"key": "post_id",
"used_key_parts": [
"post_id"
],
"key_length": "8",
"ref": [
"*_wpsmbe.wpsmbe_postmeta.post_id"
],
"rows_examined_per_scan": 13,
"rows_produced_per_join": 1044,
"filtered": "6.99",
"cost_info": {
"read_cost": "14956.78",
"eval_cost": "208.95",
"prefix_cost": "38629.34",
"data_read_per_join": "1M"
},
"used_columns": [
"post_id",
"meta_key",
"meta_value"
],
"attached_condition": "((`*_wpsmbe`.`mt1`.`meta_key` = '_wpc_expires') and (cast(`*_wpsmbe`.`mt1`.`meta_value` as signed) between '1547029897' and '1547289097'))"
}
}
]
}
}
}
}
对于世界：
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "439929.51"
},
"ordering_operation": {
"using_filesort": true,
"grouping_operation": {
"using_temporary_table": true,
"using_filesort": false,
"nested_loop": [
{
"table": {
"table_name": "wpsmcp_postmeta",
"access_type": "ref",
"possible_keys": [
"post_id",
"meta_key"
],
"key": "meta_key",
"used_key_parts": [
"meta_key"
],
"key_length": "767",
"ref": [
"const"
],
"rows_examined_per_scan": 34921,
"rows_produced_per_join": 34921,
"filtered": "100.00",
"cost_info": {
"read_cost": "24303.00",
"eval_cost": "6984.20",
"prefix_cost": "31287.20",
"data_read_per_join": "35M"
},
"used_columns": [
"post_id",
"meta_key",
"meta_value"
],
"attached_condition": "((`*_wpsmcp`.`wpsmcp_postmeta`.`meta_key` <=> '_wpc_expires') and (`*_wpsmcp`.`wpsmcp_postmeta`.`meta_key` = '_wpc_expires'))"
}
},
{
"table": {
"table_name": "wpsmcp_posts",
"access_type": "eq_ref",
"possible_keys": [
"PRIMARY",
"type_status_date"
],
"key": "PRIMARY",
"used_key_parts": [
"ID"
],
"key_length": "8",
"ref": [
"*_wpsmcp.wpsmcp_postmeta.post_id"
],
"rows_examined_per_scan": 1,
"rows_produced_per_join": 27783,
"filtered": "79.56",
"cost_info": {
"read_cost": "34921.00",
"eval_cost": "5556.62",
"prefix_cost": "73192.40",
"data_read_per_join": "97M"
},
"used_columns": [
"ID",
"post_status",
"post_type"
],
"attached_condition": "((`*_wpsmcp`.`wpsmcp_posts`.`post_type` = 'coupon') and ((`*_wpsmcp`.`wpsmcp_posts`.`post_status` = 'publish') or (`*_wpsmcp`.`wpsmcp_posts`.`post_status` = 'private')))"
}
},
{
"table": {
"table_name": "mt1",
"access_type": "ref",
"possible_keys": [
"post_id",
"meta_key"
],
"key": "post_id",
"used_key_parts": [
"post_id"
],
"key_length": "8",
"ref": [
"*_wpsmcp.wpsmcp_postmeta.post_id"
],
"rows_examined_per_scan": 11,
"rows_produced_per_join": 24298,
"filtered": "7.95",
"cost_info": {
"read_cost": "305614.26",
"eval_cost": "4859.76",
"prefix_cost": "439929.51",
"data_read_per_join": "24M"
},
"used_columns": [
"post_id",
"meta_key",
"meta_value"
],
"attached_condition": "((`*_wpsmcp`.`mt1`.`meta_key` = '_wpc_expires') and (cast(`*_wpsmcp`.`mt1`.`meta_value` as signed) between '1547025281' and '1547284481'))"
}
}
]
}
}
}
}
您能帮我所有这些信息吗？我是否必须添加索引？还是其他？
谢谢