0
votes
2answers
36 views

Why search by date field requires engine to touch all records?

Why search by date field requires engine to touch all records? Is there any way to avoid it? Following query EXPLAIN select * FROM playdays where realdate>=Date('2010,01,01') ; shows that ...
2
votes
1answer
46 views

Understanding postgres reason for picking this query plan

I ran a query: select * from orderline where orderid = 12345 and status > 0 that gave me the following plan: Bitmap Heap Scan on orderline (cost=286370.00..531410.78 rows=76372 width=155) ...
0
votes
2answers
201 views

Is there any manual for the visual explain in mysql? The output plan is unreadable

Just like this example, I cannot even tell the join ordering from it. And what does "ALL" and "ref" in the table mean? Is there any manual about the visual explain?
2
votes
2answers
1k views

Understanding time format of the EXPLAIN command - Postgres

When I run the EXPLAIN ANALYZE command on a given query, I'm having a difficult time interpreting the outputted time value. For example (actual time=8163.890..8163.893). Do the internal decimals ...
1
vote
1answer
442 views

What does HSJOIN mean in an Explain Plan?

I have the following EXPLAIN PLAN results from a query on my DB2 database. 0 SELECT STATEMENT ( Estimated Costs = 5.928E+02 [timerons] ) 1 RETURN 2 HSJOIN 3 [O] ...