Menu
For example, from the EXPLAIN documentation:
EXPLAIN SELECT * FROM tenk1; QUERY PLAN ------------------------------------------------------------- Seq Scan on tenk1 (cost=0.00..458.00 rows=10000 width=244)
What does width=244 mean?
308
This is the "Estimated average width (in bytes) of rows output by this plan node"
The ANALYZE option causes the statement to be actually executed, not only planned. Then actual run time statistics are added to the display, including the total elapsed time expended within each plan node (in milliseconds) and the total number of rows it actually returned.
Understanding the Postgres EXPLAIN cost It returns the execution plan generated by PostgreSQL query planner for a given statement. The EXPLAIN command specifies whether the tables referenced in a statement will be searched using an index scan or a sequential scan.
Cost is the estimated amount of work the plan will do. A higher cardinality => you're going to fetch more rows => you're going to do more work => the query will take longer. Thus the cost is (usually) higher. All other things being equal, a query with a higher cost will use more resources and thus take longer to run.
This is the "Estimated average width (in bytes) of rows output by this plan node"
Basically each row returned will be 244 bytes.
See Explain for more details.
169
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
