equivalent to a < x OR a > y There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally. To check whether a value (in bytes) of rows output by this plan node The costs are measured in units of disk page fetches. (CPU effort estimates are converted into disk-page units using some fairly arbitrary fudge factors. If you is estimated at 233 page reads, defined as costing 1.0 apiece, plus 10000 * cpu_tuple_cost which is currently 0.01 (try SHOW cpu_tuple_cost). Now let’s modify the query to add a WHERE condition: EXPLAIN

equivalent to a < x OR a > y There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally. To check whether a value (in bytes) of rows output by this plan node The costs are measured in units of disk page fetches. (CPU effort estimates are converted into disk- page units using some fairly arbitrary fudge factors. If is estimated at 233 page reads, defined as costing 1.0 apiece, plus 10000 * cpu_tuple_cost which is currently 0.01 (try SHOW cpu_tuple_cost). Now let’s modify the query to add a WHERE condition: EXPLAIN

equivalent to a < x OR a > y There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally. BETWEEN SYMMETRIC is the same in units of disk page fetches; that is, 1.0 equals one sequential disk page read, by definition. (CPU effort estimates are made too; they are converted into disk-page units using some fairly arbitrary is estimated at 358 page reads, defined as costing 1.0 apiece, plus 10000 * cpu_tuple_cost which is typically 0.01 (try SHOW cpu_tuple_cost). Now let’s modify the query to add a WHERE condition: EXPLAIN

equivalent to a < x OR a > y There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally. BETWEEN SYMMETRIC is the same in units of disk page fetches; that is, 1.0 equals one sequential disk page read, by definition. (CPU effort estimates are made too; they are converted into disk-page units using some fairly arbitrary is estimated at 358 page reads, defined as costing 1.0 apiece, plus 10000 * cpu_tuple_cost which is typically 0.01 (try SHOW cpu_tuple_cost). Now let’s modify the query to add a WHERE condition: EXPLAIN

equivalent to a < x OR a > y There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally. BETWEEN SYMMETRIC is the same the cost is estimated at 358 page reads, costing seq_page_cost apiece (1.0 by default), plus 10000 * cpu_tuple_cost which is 0.01 by default. Now let’s modify the query to add a WHERE condition: EXPLAIN visit all 10000 rows, so the cost hasn’t decreased; in fact it has gone up a bit to reflect the extra CPU time spent checking the WHERE condition. The actual number of rows this query would select is 7000

equivalent to a < x OR a > y There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally. BETWEEN SYMMETRIC is the same the cost is estimated at 358 page reads, costing seq_page_cost apiece (1.0 by default), plus 10000 * cpu_tuple_cost which is 0.01 by default. Now let’s modify the query to add a WHERE condition: EXPLAIN visit all 10000 rows, so the cost hasn’t decreased; in fact it has gone up a bit to reflect the extra CPU time spent checking the WHERE condition. The actual number of rows this query would select is 7000

equivalent to a < x OR a > y There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally. BETWEEN SYMMETRIC is the same The estimated cost is (disk pages read * seq_page_cost) + (rows scanned * cpu_tuple_cost). By default, seq_page_cost is 1.0 and cpu_tuple_cost is 0.01. So the estimated cost is (358 * 1.0) + (10000 * 0.01) so the cost hasn’t decreased; in fact it has gone up a bit (by 10000 * cpu_operator_cost, to be exact) to reflect the extra CPU time spent checking the WHERE condition. The actual number of rows this

equivalent to a < x OR a > y There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally. BETWEEN SYMMETRIC is the same The estimated cost is (disk pages read * seq_page_cost) + (rows scanned * cpu_tuple_cost). By default, seq_page_cost is 1.0 and cpu_tuple_cost is 0.01. So the estimated cost is (358 * 1.0) + (10000 * 0.01) so the cost hasn’t decreased; in fact it has gone up a bit (by 10000 * cpu_operator_cost, to be exact) to reflect the extra CPU time spent checking the WHERE condition. The actual number of rows this

three types, apart from increased storage space when using the blank-padded type, and a few extra CPU cycles to check the length when storing into a length-constrained column. While character(n) has performance cost is computed as (disk pages read * seq_page_cost) + (rows scanned * cpu_tuple_cost). By default, seq_page_cost is 1.0 and cpu_tuple_cost is 0.01, so the estimated cost is (358 * 1.0) + (10000 * 0.01) so the cost hasn’t decreased; in fact it has gone up a bit (by 10000 * cpu_operator_cost, to be exact) to reflect the extra CPU time spent checking the WHERE condition. The actual number of rows this

three types, apart from increased storage space when using the blank-padded type, and a few extra CPU cycles to check the length when storing into a length-constrained column. While character(n) has performance cost is computed as (disk pages read * seq_page_cost) + (rows scanned * cpu_tuple_cost). By default, seq_page_cost is 1.0 and cpu_tuple_cost is 0.01, so the estimated cost is (358 * 1.0) + (10000 * 0.01) so the cost hasn’t decreased; in fact it has gone up a bit (by 10000 * cpu_operator_cost, to be exact) to reflect the extra CPU time spent checking the WHERE condition. The actual number of rows this