Question : My user can EXPLAIN PLAN FOR any query I like, but not for CREATE INDEX. I need to […]
Tag: explain
What does “Rows Removed by Index Recheck” without “lossy” mean?
Question : Here’s part of an EXPLAIN ANALYZE from Postgres 9.6: -> Bitmap Heap Scan on cities (cost=90.05..806.49 rows=265 width=4) […]
what is “planSummary: IDHACK”?
Question : This Query scans only one document and returns only one document. But this is very slow: 2017-05-22T07:13:24.548+0000 I […]
Query results in a strange explain output
Question : So I have a medium sized query that hits 15 tables. The query takes 36 sec on MySQL […]
MySQL Explain has different row count than slow query log
Question : I have this entry in slow query log: # User@Host: user[host] @ [ip] # Thread_id: 1514428 Schema: db […]
PostgreSQL is skipping indexes when using `order by` + `limit`
Question : I have a postgreSQL database with two big tables, connections and sessions select “c”.”id” “id”, “ch”.”title” “channel”, “ch”.”name” […]
Create an explain plan for query over a global temporary table
Question : I have a query which aggregates data from a global temporary table. The table will be filled right […]
Identical query, tables, but different EXPLAIN and performance
Question : I have two tables levels and users_favorites +——————–+————–+——+—–+———+——-+ | Field | Type | Null | Key | Default […]
Postgres multiple joins slow query, how to store default child record
Question : Ive got a small database in Postgres, about 10,000 records storing company customers. I have a “slow” performing […]
Why can I execute this query but not see its execution plan?
Question : Consider the following query: SELECT table_name, to_number(extractvalue(xmltype(dbms_xmlgen.getxml(‘select count(*) c from ‘ ||owner ||’.’ ||table_name)),’/ROWSET/ROW/C’)) AS COUNT FROM all_tables […]