[Oracle] oracledba6 SQL Tuning sets, oracledba6tuning
You want to use the SQL Tuning Advisor to generate recommendation
S for badly written SQL statements in your development environment. W
Hich three sources can you select for
Label:You want to use the SQL Tuning Advisor to generate recommendations for badly written SQL statements in your development environment. WHich Three sources can you select for the advisor to analyze? (ChooseThree.)A. Top SQLB. SnapshotsC. SQL Tuning SetsD. Index Access Pat
Label:You want to use the SQL Tuning Advisor to generate recommendations for badly written SQL statements in your development environment. WHich Three sources can you select for the advisor to analyze? (ChooseThree.)A. Top SQLB. SnapshotsC. SQL Tuning SetsD. Index Access Pat
SQL execution is slow, how fast and accurate optimization.
SQLHC is one of the best tools.
By getting all the SQL execution plans, list the actual performance bottlenecks, listing the number of rows on the table where SQL resides, the data and distribution of each column, the existing index, the actual execution of
to go. In the development, we have to do some optimization of business logic, to avoid complex logic operations, especially to avoid a very large number of cycles of business logic processing, on the one hand we want to simplify business logic, some business logic to the program to deal with, on the other hand we can use SQL very clever to achieve a lot of logic complex requirements, Avoid having to do a lot of complex logic processing, rather than
August 14, 2017, a city of Oracle related Scheduler ETL extraction speed is very slow, the average SQL statement execution time of about 9 seconds, if shown:650) this.width=650; "Src=" http://img.blog.csdn.net/20170814133720856?watermark/2/text/ ahr0cdovl2jsb2cuy3nkbi5uzxqvd3d3x3h1zv94aq==/font/5a6l5l2t/fontsize/400/fill/i0jbqkfcma==/dissolve/70/gravity/ Center "width=" "style=" border:0px;vertical-align:mi
is much higher than that of the composite Index query efficiency, while in 11.2.0.3 version Verify that the ad hoc query efficiency of the common composite index is more efficient than the efficiency of the bitmap index) Create TableT (name_id, gender not NULL, location not NULL, Age_range not NULL, data) as Selectrownum, Decode ( Floor(Dbms_random.value (0,2)),0,'M',1,'F') gender, Ceil (Dbms_random.value (0, -) Location , decode ( Floor(Dbms_random.value (0,4)),0,' Child',1,' Young',2,'Middle
add data to the table (delete, update operations, and so on), add the address of the new record to the index, which slows down the new data. Presumably, to be able to read it, it's not exactly right. Knowing the index, we can add the appropriate index above the table to improve the performance of the query statement.You can look at an index as a unique table, SQL query, if the field is indexed field will be indexed to query, then the index of this un
1. New tuning Set Object ***************************************** ---Authorize grant administer any SQL TUNING SET to Scott;---Delete the existing stsbegin Dbms_sqltune. Drop_sqlset (sqlset_name = ' ocpyang_sts '); end;/---new Stsbegin dbms_sqltune. Create_sqlset (sqlset_name = ' ocpyang_sts ', Sqlset_owner = ' SCOTT ', description = ' ocpyangtest '); end;/---Vi
Label:A recent project involves data-table queries of large data volumes. The total data table is about 700 million-2 billion, the primary key to establish a global unique index, the partition policy is hash partition + range partition, most of the time the query condition hit record more than million, a single return to the previous XX record. The following experiences are summed up in the tuning process:(1) Minimize the interval limit, even if the a
Oracle SQL Tuning Health Check ScriptWe focus on the performance of database system, the main task of database tuning is to optimize SQL. Good data architecture design, with application system middleware and writing a beautiful SQL
Tags: process optimizer consolidation requires merging auto overwrite session accessThe full execution order of the SELECT statement:The full execution order of the SQL SELECT statement: 1. The FROM clause assembles data from different data sources; 2. The WHERE clause filters the record rows based on the specified criteria, 3, the GROUP BY clause divides the data into multiple groupings, 4, uses the aggregation function for the calculation, 5, uses t
time and reduce the syntax errors caused by the column ambiguity. 14. Replace distinct with exists:When submitting a query that contains one-to-many table information, avoid using DISTINCT in the SELECT clause. You can generally consider replacing with exists Example: (Low efficiency) Select from where d.dept_no = e.dept_no; Efficient Select from where exists (select1fromwhere d.dept_no = e.dept_no); exists makes queries faster because the RDBMS core module returns results immediately after t
Oracle SQL advanced programming learning notes (I) SQL Execution theory 1. Shared Pool SGA1, each SQL statement executed contains parsed content in the shared pool, these statements are stored in the library cache ). no matter how many users want to execute the same
is recommended for use with this select NO, listagg (EMP, ', ') within GROUP (ORDER by NULL) as Valsfrom onepiecegroupAbove we see the Listagg function syntax has over function, of course, our Listagg can also do analysis functionsSELECT NO, listagg (EMP, ', ') within GROUP (ORDER by NULL) through (partition by NO) from onepieceThe 3rd method of implementation has the To_string function, where the source code is as follows:CREATE OR REPLACE FUNCTION to_string (nt_in in Varchar2
rationally;② Historical Data Quick cleanup: ALTER TABLE t truncate partition P1;.Disadvantages:① too many partitions also increase overhead, and in general, tables above the million data level are considered for partitioning.② too many partitions also result in a workload on partition maintenance.4. Index Organization table (index-organized Tables)The table itself is the index, and the index itself is the table. For configuration tables that are rarely updated.Pros: eliminate back tables and ap
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