New Feature IDENTITY Columns

In Oracle 12c when we create a table we can populate a column automatically via a system generated sequence by using the GENERATED AS ++ clause in the CREATE TABLE statement. We can use GENERATED AS IDENTITY with the ALWAYS, DEFAULT or DEFAULT ON NULL keywords and that will affect the way or when the identity column value is populated. By default the GENERATED AS IDENTITY clause implicitly includes the ALWAYS keyword i.e GENERATED ALWAYS AS IDENTITY. When the ALWAYS keyword is specified it is not possible to explicitly include values for the identity column in INSERT OR UPDATE SQL Read More

Move listener log to another filesystem

Run lsnrctl command to change listener’s settings: [db000oracle@]/app/oracle/listener/log > lsnrctl Set the listener interested: LSNRCTL> set current_listener LSNR_[db_name] Current Listener is LSNR_[db_name] LSNRCTL> show log_status Connecting to (ADDRESS=(PROTOCOL=IPC)(KEY=BSCS)) LSNR_[db_name] parameter “log_status” set to ON The command completed successfully Change log_status to off so you can move the associated log: LSNRCTL> set log_status OFF Connecting to (ADDRESS=(PROTOCOL=IPC)(KEY=BSCS)) listener_[db_name] parameter “log_status” set to OFF The command completed successfully At this point, you may rename the file and move it to the new directory mv listener_[db_name].log listener_[db_name].log_[date] mv listener_[db_name].log_[date] /LSNR_LOG Recreate the file you just renamed: touch listener_[db_name].log By now is possible to Read More

ORACLE 12C : Advanced Index compression

Oracle 12c rel.1 ( introduced a new method for index compression called “advanced index compression” which is more effective in index compression than available methods in Oracle 11g . Creating an index using advanced index compression reduces the size of unique and non-unique indexes. Advanced index compression improves the compression ratios significantly . Advanced Index Compression is not supported for bitmap indexes and for indexes on unique single-column indexes. For a partitioned index, you can specify the compression type on a partition . You can also specify advanced index compression on index partitions even when the parent index is not Read More

6-11g Release 2 RMAN Backup Compression

Oracle 11g Release 2 introduced compression algorithm levels which can be used for compressing table data,Data Pump exports and RMAN backups as well. The compression levels are BASIC, LOW, MEDIUM and HIGH and each affords a trade off related to backup througput and the degree of compression afforded. To use this option, we can run the following RMAN commands RMAN> CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO COMPRESSED BACKUPSET; followed by .. RMAN> CONFIGURE COMPRESSION ALGORITHM ĹHIGHĺ; or RMAN> CONFIGURE COMPRESSION ALGORITHM ĹMEDIUMĺ; or RMAN> CONFIGURE COMPRESSION ALGORITHM ĹLOWĺ; or RMAN> CONFIGURE COMPRESSION ALGORITHM ĹBASICĺ; Tests carried out on a Read More

Oracle Public Cloud Services: IOT (parte 3)

My preceding articles discussed some general topics about Oracle Cloud Services. Well, cloud services are a great thing, I agree, but some of you could put the following question: “Is there any application or family of applications specifically suited to run in the cloud?” Perhaps there are many, but one of them is currently under the spot: Internet of Things or shortly IoT. INTERNET OF THINGS Acquire, manage and analyze data sent by a network of physical devices (from simple sensors to flyng drones) Data is used to monitor and control a geographically distributed service, but also to improve its Read More

Oracle Public Cloud Services. Security (part 2 of 3)

In my preceding article I tried to explain how companies and Oracle partners can take advantage of the Oracle Cloud and its different and powerful services. Have I missed something? Yes, SECURITY. All of the services belonging to the Oracle Cloud are offered as public (i.e. shared by multiple companies) or private (i.e. used by a single, large company). A public cloud is inherently unsafe, you know, but even a private one could open security holes if badly managed. Luckily, security is one of the major strengths of the Oracle Cloud proposal. First of all, any service must be accessed Read More