Oracle Exadata is the database server designed by Oracle, the fastest, powerful intelligence machine that provides its optimized functionality to the users related to the user databases and their defined workloads. In simpler terms, Oracle Exadata is a computing platform optimized for running the Oracle database. It is essential to know about Oracle Exadata as it will boom in the next generations as business requirements change only on a timely basis. In this article, you can go through the set of Oracle Exadata interview questions most frequently asked in the interview panel. And these lists will help you crack the interview as the topmost industry experts curate these at HKR training. Let us have a quick review of the Oracle Exadata interview questions
Ans: Exadata in Oracle refers to the pre-configured combination of software and hardware specifically designed to provide a platform to run the Oracle database. Oracle Exadata is a modern framework intended to run the databases and scale-out the database servers.
Advantages of Oracle Exadata:
Oracle Exadata includes an Exadata cluster that is compatible to deliver a consistent performance along with increased throughput. Oracle Exadata uses inter-instance and inter-instance parallelism that results in consistency though the load increases on the cluster.
Ans: Oracle Exadata is configured with many features in it. The features of Oracle Exadata are listed below:
Smart Scan: Smart scan in Exadata is a unique feature capable of enhancing the database's performance as many times as needed. A smart scan helps in processing the queries and intelligently retrieves specific rows in the table.It applies to filter criteria and column projection, which is selection criteria.
Smart Flash Cache: The smart flash cache is a hardware component that delivers high performance configured in the Exadata storage cell server. The performance improved by using the read and write operations. Smart flash cache helps in holding the frequently accessed data. This would help in easy access whenever the users need the same data. This helps in avoiding the physical read by allowing the data to be read from the physical cache.
IORM: IORM refers to Input/output Resource Manager. IORM is specifically used to manage the I/O using the configuration information with the number of resources available. It helps in maintaining the incoming requests at a consumer group level.
Storage Index: Storage index is one of the features in the Exadata database machine, which is used to reduce the I/O amount for an Exadata smart scan.
EHCC: EHCC refers to Exadata Hybrid Columnar Compression, which helps in compressing the data at the column level in a table. It helps create the compression data units, including logical grouping of the columns from the available multiple rows.
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Ans: The following are the key hardware components of Exadata.
The performance of Exadata can be tested using the calibrate commands at the cellcli command line.
Ans: The firmware of the Exadata components can be upgraded using the ILOM of the database or cell server.
Ans: ASR refers to Auto Service request, a tool that is designed to manage the Oracle hardware. The Auto service request tool will automatically raise a service request when any issues arise with respect to the hardware. Based on the request sent, it will send the appropriate notification to respective customers.
The following are the prerequisites to be followed to configure ASR:
Ans: Exadata is good for the environment, which includes data warehouses. Further, the enhancement is done to be used in the OLTP databases as well.
Ans: Cell and grid disk represents the logical part of the Exadata storage. The disk drives are used to store the data. Cell disk is the combination of all the disks together to store the user data. Every cell disk is linked with the logical unit, which includes 12 hard disk drives that are mapped to it. Grid Disks are presented to the ASM and ASM disks that are built upon the cell disks. Grid disks include the space allocation that is available in the outer tracks of the cell in chunks.
The list cell disk command can be issued at the cellcli command to obtain the information on the cell disk.No, Cell disk can have multiple grid disk, but grid disk cannot have various cell disk.
Ans: Storage index is the feature available in Exadata used to reduce the amount of I/O required to service the requests. The storage index includes both maximum and minimum value, upto eight columns. Storage indexes are never written to the disks and they are used to filter the required data. Storage indexes can be stored only in memory. No, it is not possible to intervene in the storage index.
Ans: There are three different options available to update the cell_flashcache for any object. They are listed below:
The Cell_flashcache compression is enabled by using the following command: CellCLI>ALTER CELL flashCacheCompress=true.
Ans: Multiple ways are available to migrate onto Exadata. These are dependent on the downtime. They are listed below:
Ans: Cellcli refers to the cell command-line utility. By using the cellcli utility, cell storage can be managed. It is the cell storage that is used to administer the cell storage. It includes different commands like CELLCLI-ALTER, CELLCLI-CREATE, CELLCLI-LIST, CELLCLI-DROP.
DCLI refers to the distributed command-line utility. It is the command-line utility specifically designed to replicate command on database servers and multiple storage.
Ans: There are three different networks available in Exadata. They are listed below:
Ans: DBRM stands for database request module, a traditional database model that allows representation of SQL statements in a serial format in a program.
IORM stands for Input/Output (I/O) Resource is a tool specifically designed for management of the multiple databases and workloads by sharing the I/O resources of the Oracle Exadata System Software.
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Ans: DBFS stands for Database File System, which helps create a standard interface represented in the form of files and directories in the database tables.
The following are the steps to be followed to create DBFS.
Ans: The following is the migration methodology that is available to migrate from high endian to low endian OS architecture.
Ans: EHCC refers to Exadata Hybrid Columnar Compression used to perform compression of the data in the database. There are different types of EHCC available. They are listed below:
Smart Scan Offloading: Exadata Smart scan offloading allows the processing of the queries from the database server to the storage server. The Exadata storage servers consist of the processors that will perform data processing. The data that is requested will be shared and returned to the database server.
Offload Block filtering: Offload block filtering is an option available in the Exadata storage server that allows filtering of the blocks that are not required or utilized for the incremental backup. Using this, the required blocks of data backup are sent to the database.
Ans: There is a tool designed to generate the initial configuration files based on the customer-related data called Oracle Exadata Deployment Assistance (OEDA).
Ans: The write-through is an option available to use the reading mode. In simple terms, write-through is used in the flash cache for reading purposes.
The write-back is the option available to be used in both reading and writing mode. In simpler terms, write-back is used in the flash cache to perform both reading and writing operations.
Ans: The spine switch in Exadata is designed to establish connectivity or add more Exadata machines in the cluster. The Infiniband spine switch is used to connect and expand the Exadata racks.
Ans: The parallel instance parameter that is used in Exadata is PARAMETER_FORCE_LOCAL. This parameter is specified at the session level for a particular job.
Ans: Oracle Exadata exhibits higher throughput as it has the capability to ship fewer data in the form of pipes between the storage and database nodes and other nodes in the RAC cluster. Oracle Exadata can run multiple processes at a time across all the nodes in the cluster, which provides higher throughput. It uses big pipes, making use of the Infiniband interconnect for the data transfer in the form of blocks. The transfer rate is five times the fiber channel networks.
Ans: IDB stands for Intelligent Database protocol that is designed to establish the connectivity or communication between the database server and the storage cell.
The following are the different health check tools available:
Ans: The capacity that could be handled in Infiniband port is 40Gbps.The flash cache is the feature that is available to eliminate the disk I/O in Exadata.
Ans: The default size of the smart flash log is 512 MB per module.Each storage cell consists of 4 modules, so it will be 4* 512 MB per cell.
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Ans: Several methods can be followed to migrate the database from the normal setup to the Exadata. They are listed below:
Ans: The following are the steps to be followed to integrate the Exadata with OEM 12 c.
Ans: DBMS_COMPRESSION is the package that is available in Exadata to estimate the compression ratio of a table.
Ans: LIBCELL in Exadata refers to Library Cell that is interlinked with the Oracle Kernel. LIBCELL helps in establishing the communication between the Oracle Kernel and the storage server. This communication establishment is network-based. It does not use the operating system reads and writes. 53 wait events are available in the 184.108.40.206 release.
Ans: Check ip in Exadata is an OS-based script. Checkip consists of the IP address and the hostname. Exadata uses this information in the configuration phase. It ensures that there is no IP duplication in the network by adding some pings to check. It also primarily checks the readiness of the network that includes DNS configuration.