How do I narrow my search results?
After you submit your search query:
- On the Refine Search results page, select one or more categories of products or services from the left sidebar.
- Then for a category with search results, click Select to choose your product and release filters, and then click OK.
For search queries that contain multiple words, surround the query with quotes, and then resubmit your query. Example: "database cloud service"
How do I find the documentation for my product or service?
From the home page, click the technology categories for your products or services. If you do not know which category to pick, try the following features:
- Click the Find a product tab and search for your product or service.
- Click Browse All Products & Services at the bottom of the home page to view an alphabetical listing of products and services.
- Apple Safari: Version 6
- Google Chrome: Version 29 and later
- Mozilla Firefox: Version 24 and later
- Microsoft Internet Explorer: Version 9 and later
FIRST_ROWS Hint → Description of the illustration first_rows_hint.gif The FIRST_ROWS hint instructs Oracle to … /*+ FIRST_ROWS(10) */ employee_id, last_name, salary, job_id FROM employees WHERE department_id = 20 … Hint" for additional information on the FIRST_ROWS hint and statistics
7.2.2 FIRST_ROWS(n) Mode → In FIRST_ROWS(n) mode, the optimizer in Oracle Database optimizes for fast response time by having … use the FIRST_ROWS(n) hint. If you want to optimize for better throughput under FIRST_ROWS(n), you … rows that satisfy the CONTAINS predicate are retrieved from the index: select /*+ FIRST_ROWS(10 … query optimizer
SDO_NN_DISTANCE Performance Improvement with FIRST_ROWS Hint → performance when you specify the FIRST_ROWS optimizer hint. For an example of using the FIRST_ROWS
7.1.2 Improved Response Time with FIRST_ROWS(n) Hint for ORDER BY Queries → FIRST_ROWS(n) hint. You use the FIRST_ROWS(n) hint in cases where you want the first number ( n ) of … cursor to retrieve the first 10 hits of a query and uses the FIRST_ROWS(n) hint to optimize the response … time: declare cursor c is select /*+ FIRST_ROWS(10) */ article_id from articles_tab where contains
ALL_ROWS Hint → employee_id = 107; If you specify either the ALL_ROWS or the FIRST_ROWS hint in a SQL statement, and if … FIRST_ROWS hint, then the optimizer gives precedence to the access paths and join operations specified by the hints.
Table 3-21 Hints by Functional Category → Hint Link to Syntax and Semantics Optimization Goals and Approaches ALL_ROWS Hint FIRST_ROWS Hint
Optimizer Hints → AUTOTRACE output in Example 7-4. Example 7-4 Execution Plan for SELECT with FIRST_ROWS Hint SELECT … /*+ FIRST_ROWS(25) */ employee_id, department_id FROM hr.employees WHERE department_id > 50
Use of the Optimizer → as possible. Initial response time The FIRST_ROWS hint instructs the optimizer to get the first row
OPTIMIZER_MODE → | 1000] | first_rows | all_rows } Default value all_rows Modifiable ALTER SESSION, ALTER SYSTEM … time to return the first n rows (where n = 1, 10, 100, 1000). first_rows The optimizer uses a mix
19.1 Overview of Optimizer Hints → : SELECT /*+ FIRST_ROWS(10) */ * FROM employees; See Also: Oracle Database SQL Language Reference to a complete list of hints supported by Oracle Database
21.6.2 Sample TKPROF Body → 0.00 0 0 0 0 Misses in library cache during parse: 1 Optimizer mode: FIRST_ROWS Parsing user id: 44 … ------- ------ -------- ---------- ---------- ---------- ---------- ---------- total 4 0.02 0.01 0 15 0 1 Misses in library cache during parse: 1 Optimizer mode: FIRST_ROWS
11.5.2 Choosing an Optimizer Goal → 1, 10, 100, or 1000. FIRST_ROWS The optimizer uses a mix of cost and heuristics to find a best plan … the heuristic. FIRST_ROWS is available for backward compatibility and plan stability; use
Table 11-5 Hints for Changing the Query Optimizer Goal → Hint Description FIRST_ROWS( n ) This hint instructs Oracle Database to optimize an individual SQL
7.7.9 How do I make an ORDER BY score query faster? → Answer: Sorting by relevance ( SCORE(n) ) can be extremely quick if the FIRST_ROWS(n) hint is used … tables. An example of such a query: SELECT /*+ FIRST_ROWS(10) */ ID, SCORE(1), TEXT FROM mytable WHERE
Initialization Parameters for Query Rewrite → : OPTIMIZER_MODE = ALL_ROWS (default), FIRST_ROWS, or FIRST_ROWS_ n With OPTIMIZER_MODE set to FIRST_ROWS, the
Contents → DYNAMIC_SAMPLING Hint FACT Hint FIRST_ROWS Hint FULL Hint HASH Hint IGNORE_ROW_ON_DUPKEY_INDEX Hint INDEX
How Oracle Database Processes DML → * FROM my_table; ALTER SESSION SET OPTIMIZER_MODE=FIRST_ROWS; SELECT * FROM my_table; ALTER SESSION SET
Ensuring that Query Rewrite Takes Effect → OPTIMIZER_MODE to ALL_ROWS, FIRST_ROWS, or FIRST_ROWS_ n. If step 1 has not been completed, a
19.1.2 Hints by Category → ALL_ROWS and FIRST_ROWS( n ) hints let you choose between optimization approaches and goals. If a SQL … not affect SQL run within PL/SQL. If you specify either the ALL_ROWS or the FIRST_ROWS ( n ) hint … you specify hints for access paths or join operations along with either the ALL_ROWS or FIRST_ROWS