Tagged: Oracle database

Oracle Database

How to drop and create a Temporary Tablespace

Temporary tablespaces are used to manage space for database sort operations and for storing global temporary tables. For example, if you join two large tables, and Oracle cannot do the sort in memory (see SORT_AREA_SIZE initialization parameter), space will be allocated in a temporary tablespace for doing the sort operation. Other SQL operations that might require disk sorting are: CREATE INDEX, ANALYZE, Select DISTINCT, ORDER BY, GROUP BY, UNION, INTERSECT, MINUS, Sort-Merge joins, etc.

Oracle Database

How to restore the OCR and Voting disk when they are lost

11gR2 – Restore OCR/ VOTEDISK based on ASM, when loss of CRS Diskgroup. Labels: 11GR2, loss of CRS Diskgroup, lost OCR on ASM, RAC, RESTORE OCR, RESTORE OCR ON ASM, RESTORE VOTEDISK Locate the latest automatic OCR backu When using a non-shared CRS home, automatic OCR backups can be located on any node of the cluster, consequently all nodes need to be checked for the most recent backup: $ ls -lrt $CRS_HOME/cdata/rac_cluster1/ -rw——- 1 root root 7331840 Mar 10 18:52 week.ocr -rw——- 1 root root 7651328 Mar 26 01:33 week_.ocr -rw——- 1 root root 7651328 Mar 29 01:33 day.ocr -rw——-...

Oracle Database

Create Oracle SQL Profile For Tuning

Looking for how to tune a SQL statement by creating a SQL Profile? The query optimizer can sometimes produce inaccurate estimates about an attribute of a statement due to lack of information, leading to poor execution plans. Automatic SQL Tuning deals with this problem with its SQL Profiling capability. The Automatic Tuning Optimizer creates a profile of the SQL statement called a SQL Profile, consisting of auxiliary statistics specific to that statement. During SQL Profiling, the Automatic Tuning Optimizer also uses execution history information of the SQL statement to appropriately set optimizer parameter settings, such as changing the OPTIMIZER_MODE initialization...

Oracle Database

Pivot and Unpivot

These keyword was introduced in Oracle 11g. The UNPIVOT operator transforms the data arranged on a column into separate rows. With this utility it is possible to convert the display of the data to have them displayed on columns to have them on lines. In this example we talk about the prices associated with a ticket: UNPIVOT : SELECT * FROM tickets ; Applying the unpivot: pivoting on the ticket column it is possible to see the opening and closing price on separate lines. SELECT ticket,to_char(ticket_date,’YYYYMMDD’)ticket_date,price_type,price FROM tickets UNPIVOT ( price FOR price_type IN ( opening_price AS ‘OPEN’, closing_price AS...

Cloud / Cloud System / Oracle Application

What is cloud computing?

Aspects and definition of the SaaS, PaaS, DaaS, IaaS platforms. What is cloud computing? Possibility of relying on a specialized provider for the management of one or more IT resources that, from that moment on, are provided via the Web through an outsourcing contract. All this, without the company having to bear the costs of purchasing licenses or machines to take advantage of services indispensable to the business. the supplier to maintain all the infrastructure necessary to manage and distribute the services based on the request (on demand) and with a pay per use formula. All with a subscription to...

Oracle Database 12 c

ORACLE 12C : Listener service registration

With previous releases PMON (Process Monitor) was responsible for registering database services to the Listener. Starting from Oracle 12C there is a change in architecture with respect to the service registration in Oracle Database Release 12c. Oracle has introduced a new mandatory background process dedicated for “database service registration to the Listener” and named LREG (Listener Registration Process). The listener registration process (LREG) registers information about the database instance and dispatcher processes with the Oracle Net listener (see “The Oracle Net Listener”). When an instance starts, LREG polls the listener to determine whether it is running. If the listener is running,...

Database / Oracle Database

ORACLE – enq: TX row lock contention

Enqueues are locks that coordinate access to database resources. enq: wait eventindicates that the session is waiting for a lock that is held by another session. The amount of wait time associated with this wait event is excessive and can be responsible for performance issues observed in the application. TX enqueue are acquired exclusive when a transaction initiates its first change and held until the transaction does a COMMIT or ROLLBACK.  Some situations of TX enqueue: – Waits for TX in mode 6 occurs when a session is waiting for a row level lock that is already held by another...

Oracle Database / Oracle Errors

Ora-19025

When you work with xml file you should be solve the scenery that have an node with its properly sub node. In our case the following nodes () ; () . It is quite delicate find exactly approach that gives to you the requirement expected. The problems that I have got they were two different: – Duplicate row – ORA-19025 EXTRACTVALUE returns value of only one node or ORA-19279: XPTY0004 – XQuery dynamic type mismatch: expected singleton sequence – got multi-item sequence The following image shows the scenery described: Duplicate row means the query extract the values that are not...

Oracle Database / Oracle Database 12 c / Uncategorized

Create Sequence-Oracle Database 12c

Database version : from Oracle Database 12cR1 Create sequence with session or global option When a sequence number is generated, the sequence is incremented, independent of the transaction committing or rolling back. SESSION option makes opportunity to create sequence that can used in association with global temporary table then its visibility is just for session. The following options CACHE, NOCACHE, ORDER, or NOORDER are ignored when SESSION is declared. 1) statement SQL> CREATE GLOBAL TEMPORARY TABLE glb_tmp_table (a number); Table created. SQL> CREATE SEQUENCE sq_sess SESSION; Sequence created. 2) Script execution SQL> INSERT INTO glb_tmp_table VALUES (sq_sess.NEXTVAL); 1 row created....

Oracle Database / Oracle Database 12 c

ORACLE 12 rel.2 – Partitioning new features

In Oracle 12c rel.2 a great number of enhancements to the Oracle database Partitioning option have been introduced. These include: Automatic List Partitioning Filtered Partition maintenance operations Multi-Column List Partitioning Online conversion of non-partitioned to partitioned table Read-only Partitions Partitioned External Tables Automatic List Partitioning: The ability to partition a table based on distinct values in a column has been around since quite some time, but what is new in Oracle database 12.2 is that we can initially partition the table based on values that are known and present in the column we would like to partition the table on....