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...
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, 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, ...
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 ...
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_...
Has a number of different meanings used to indicate partition elimination may also indicate an actual filter step where one row source is filtering another functions such as min may introduce filter steps into query plans In this example there are 2 filter steps. The first is effectively like a...
you can see many cases of using SPI, such as the most common database driver implementation. Only the java.sql.Driver interface is defined in the JDK, and the specific implementation is provided by the database vendors. Here is a simple example to quickly understand how to use Java SPI: ...
[SQL Server Native Client 11.0]Connection is busy with results for another command [closed] [win 10, c#] Interop - Generic way to know if a window is Minimized, Maximized or Normal? [Y/N] Prompt C# \r\n not working! \t is not working but \n does #C code to Read the sectors ...