oracle performance tuning pdf

Tags: tabs Other applications ABS SSE contains increased data process structure understandingThe parameters of the tuning function in the Oracle database system are called initialization parameters, and the database administrator needs to properly adjust these initialization parameters to optimize the Oracle system according to the actual situation.1 introduction

the Set TRACE function in Sqlplus analysis of performance and index usage of statements by toad or PL/SQL developer not satisfied with Oracle default optimizations you can force the use of hint, but it is generally not recommended It is generally not recommended to index a field that stores only or no information for flag. You can use bitmap indexing if necessary * There is a recursive query situation

Oracle Adjusts Oracle's competition One of the benefits of Oracle is that it manages the free space in each table space. Oracle handles the space management of tables and indexes so that we don't have to understand the internal workings of Oracle's tables and indexes. However, for an experienced Oracle

rownumObviously, this writing will result in reading the table first, then sorting, and then taking the first 5 records, the plan is as follows:If we write like this, the semantics are the same, but it saves a lot of reading and sorting costs:Select/*+ Index (T1,IDX1_T1) */* from T1 where rownumThe execution plan for this SQL is as follows:As you can see, the SQL does not follow the hint instructions and sequentially scans the IDX1_T1 index, which is why? Personally, it may be that the

. The customer provided an AWR report during peak hours. After careful analysis, it was found that it was a high-CPU-consuming SQL statement, which only took 85% of the CPU, this gives us an in-depth understanding of SQL optimization. We have also done some DB optimization before, basically through analysis tables, index creation, parameter adjustment, PATCH, and so on. However, this time, it lasted for a week. After learning for a few days, it has not been solved yet. Finally, I decided to stud

relate to the World Cup scoring players in the club's performance, to the first form of association, first know Ronaldinho's ID number, and then find the corresponding club performance. Table 1, a row of data to the corresponding to the 1 columns of data in table 2, table 2 of the 1 columns of data to the corresponding table 1 of the 1 rows of data, in the two large tables in the million bar, this associat

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 SQL-time, IO, and the number of rows returned. Specific use of reference Document 1366133.1 SQL

Oracle Online tuning redo number of log groups and group membershipsFirst, adjust the redo log group sizeOperation Reason:Redo log general settings allow the log conversion time to 10-20 minutes, and the conversion too often affects performance. Usually do not exceed 6 times per hour! If AWR (automated Workload Repository automatic load repository) report, log fi

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

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 writing more complex SQL statements under com

-align:middle; "/>There is a question worth thinking about: developing or testing why not in the front of the application of the PID before and after the implementation of the white space function trim, rather than put on the database side to execute, which not only aggravate the workload of the database server,It is also easy to cause the full table scan of large tables due to improper use of the function to reduce the execution speed of SQL; although, creating a trim-based function index on a

using the temporary tablespace 22.8 summary Chapter 23rd pluggable Databases23.1 Understanding Pluggable Architecture23.1.1 Conversion Paradigm23.1.2 the meaning of backup and recovery operations23.1.3 Fine Tuning23.2 Creating a CDB23.2.1 creating a CDB manually using SQL commands23.2.2 using DBCA23.2.3 creating a CDB script from DBCA23.2.4 Check if the CDB has been created23.3 Managing the root container23.3.1 Connecting the root container23.3.2 displaying information for the current conn

Test environment above Oracle database performance parameter settings1. Close the Recycle BinAlter system set Recyclebin=off2. Modify the size of the redo logThe default size of 11g is 50m if redo file compares small OLTP logs more than the case will cause more redo FileSwitch recommended to modify the default size at DBCA time 500m to 1G better.If you have already created and the table is small, you can ex

sort, in order to improve the speed of database sorting, It is recommended that you try to use the memory sort area instead of the temporary segment. The sort_area_size is used to set the sorting area size.Increasing the sort area increases the performance of large-scale sorting, because it is possible to perform sorting in memory during query processing. The size of the sort area is important because there is only one sort area for each connection a

The SQL Tuning toolset (SQL Tuning set,sts) is an integral part of the Oracle 10g SQL Tuning Advisor feature. Each tuning toolset contains one or several SQL statements, as well as the contextual information needed to properly interpret them. SQL

value that does not exceed 65536, because the upper limit for each IP packet is 65,536 bytes.The sb_max--tunable parameter sets the upper limit for the number of socket buffers queued for a single socket, which can control the total amount of buffer space used by the buffer (queued for sender or received sockets). This amount should normally be less than wall and approximately 4 times times the maximum value of TCP or UDP send and receive settings.The rfc1323--tunable parameter supports the TCP

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, is the future of the system on-line no fatal perf