cursor.explain()operations can return information regarding: explainVersion, the output format version (for example,"1"). command, which details the command being explained. queryShapeHash, starting in MongoDB 8.0, which is a hexadecimal string with the hash of aquery shape. For details, seeQue...
ExplainOneQuery(Query *query, int cursorOptions, IntoClause *into, ExplainState *es, const char *queryString, ParamListInfo params, QueryEnvironment *queryEnv){ /* planner will not cope with utility statements */ if (query->commandType == CMD_UTILITY) { ExplainOneUtility(query->utilityStmt, ...
The SQL Explain Plan option generates an explain plan for a query. To generate an explain plan, either highlight a query, or if nothing is highlighted and the language type is SQL mode, separate the queries in the editor by semi-colons and position the cursor within the query to explain,...
For example, if a query shows high buffer usage, it may indicate that the query is performing a lot of disk I/O, which could be a performance bottleneck, especially if the data is not cached in memory. auto_explain.log_timing Purpose: Similar to log_analyze, this set...
To see the list of query modifiers supported by db.collection.explain().find() as well as cursor-related methods, run: db.collection.explain().find().help() You can chain multiple modifiers to db.collection.explain().find(). For an example, see Explain find() with Modifiers....
V$SQL_PLAN - A dynamic performance view that shows the execution plan for a SQL statement that has been compiled into a cursor and stored in the cursor cache. Under certain conditions the plan shown when using EXPLAIN PLAN can be different from the plan shown using V$SQL_PLAN. For example...
(a) Describe the concept of a cursor. (b) How is it used in embedded SQL? For a "Hello world" program, the kernel must copy the string from the user program memory to the screen memory. Why must the screen's buffer memory be protected?
For information on the execution plan for a cached cursor, queryV$SQL_PLAN. For execution statistics at each step or operation of an execution plan of cached cursors (for example, number of produced rows, number of blocks read), queryV$SQL_PLAN_STATISTICSview. ...
DECLARE cur_schema_names CURSOR FOR SELECT schema_name_table.schema_name FROM schema_name_table; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE; OPEN cur_schema_names; explain_loop: LOOP FETCH cur_schema_names INTO schema_name; ...
baseline_ref_cursor DBMS_SQLTUNE.SQLSET_CURSOR; BEGIN -- create sql_plan_baseline for sql using plan from AWR DBMS_SQLTUNE.CREATE_SQLSET(:ss_name); open baseline_ref_cursor for select VALUE(p) from table(DBMS_SQLTUNE.SELECT_WORKLOAD_REPOSITORY(:b_snap_id, :e_snap_id, ...