我正在使用NewRelic向我的一个Rails应用程序发出一个非常长的请求,发现许多SQL查询看起来完全是外来的,占用了相当长的时间.我已经谷歌了,但我已经空手而归,不管我是否可以防止它们发生.
SELECT COUNT(*) FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = c.relnamespace WHERE c.relkind in (?, ?) AND c.relname = ? AND n.nspname = ANY (current_schemas(false))
…和…
SELECT a.attname, format_type(a.atttypid, a.atttypmod), pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod FROM pg_attribute a LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum WHERE a.attrelid = ?::regclass AND a.attnum > ? AND NOT a.attisdropped ORDER BY a.attnum
...每次发生7次,共计145ms和135ms.
SELECT DISTINCT(attr.attname) FROM pg_attribute attr INNER JOIN pg_depend dep ON attr.attrelid = …