The following example returns the query plan for the same query with verbose output: explain verboseselecteventid, eventname,event.venueid, venuenamefromevent, venuewhereevent.venueid = venue.venueid; QUERY PLAN ---{HASHJOIN:startup_cost2.52:total_cost58653620.93:plan_rows8712:plan_width43:best...
For example, an inner join query with predicate on one table can be rewritten into a CrossJoin. This pushes the predicate down to the scanning phase of the table so that fewer data are scanned. Join distribution types Distribution types define how data is exchanged between worker nodes when ...
For example, if a hash aggregate operator is used in the first step of a query plan, full data of downstream operators is required to create a hash table for an aggregate operation. For common queries with filter conditions, data is calculated and returned in real time. In this scenario, ...
Replace invalid characters with dashes, * so that for example "I/O Read Time" becomes "I-O-Read-Time". */static voidExplainXMLTag(const char *tagname, int flags, ExplainState *es){ const char *s; const char *valid = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_."; ...
For example, J3_1_2_Stg1 indicates that the task with the ID of 3 depends on the M1 and M2 tasks. Dependencies between all operators in a task The operator string describes the execution semantics of a task. Operator string structure: In Task M2: Data source: mf_mc_bj.sale_detail...
The same example can be written in ANSI SQL as T1 LEFT OUTER JOIN T2 ON (T1.x = T2.x); Figure 21: Example plan output using OUTER JOIN. Note a join type is always matched with one of the join methods; in this case a hash join 15 THE ORACLE OPTIMIZER EXPLAIN THE EXPLAIN PLAN ...
It is initialized in the base part with the id of the random track just selected The recursive part of the CTE joins the previous record with the table, making sure that no record from the latest 10 will be selected on this step. To do this, we just use the array operator <@ (...
Example 2 -- Disable enable_stream_recursive so that associated WITH RECURSIVE queries cannot be pushed down. gaussdb=# SET enable_stream_recursive = off; -- Create the chinamap table. gaussdb=# CREATE TABLE chinamap ( id integer, pid integer, name text ) DISTRIBUTE BY hash(id); -- Plan...
to 2. EXPLAIN ANALYZE can be used with SELECT statements, multi-table UPDATE and DELETE statements, and TABLE statements. You can terminatethis statement using KILL QUERY or CTRL-C. EXPLAIN ANALYZE cannotbe used with FOR CONNECTION. Example output: mysql> SELECT @@explain_...
Map Golang Example Hash Map standard functions in golanggo run map.goTinyGoYou can even use Go on microcontrollers, the keyword here is TinyGo, a go compiler specially developed for SBCs and MCUs. If you want to blink the LED of your Raspberry Pi Pico, try this:...