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69 Cards in this Set
- Front
- Back
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Where are listener.ora and tnsnames.ora located? client or server?
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listener.ora = server
tnsnames.ora = client and server |
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Which DBA tool configures Oracle Net Services with step-by-step instructions?
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Net Configuration Assistant
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In which tool(s) can you view and modify data, table structures, indexes, views, objects, procedures and packages?
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Schema Manager, which is included in Enterprise Manager
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In which tool(s) can you view and modify users, roles and profiles, create new users, and change passwords?
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Security Manager, which is included in Enterprise Manager
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Which tool executes SQL commands, runs reports and queries, starts and stops the database?
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SQL*Plus
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Which control handles many instances from one place?
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Grid Control
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Which control handles only one instance from one place?
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Database Control
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If you need to control more than one database and/or instance using the Database control, how can you accomplish this?
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Open more than one Database Control, each one using a different port number
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What is the Unix command to open the Database Configuration Assistant?
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dbca
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Which tool creates new database instances?
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Database Configuration Assistant (DBCA)
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What is the Unix command to open the Net Configuration Assistant?
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netca
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What is the Unix command to open SQL*Plus?
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sqlplus <username>/ [<password>]
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What is the Unix command to open Enterprise Manager?
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emctl start dbconsole
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Where does Oracle Net Services reside? client or server
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both
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How does Oracle Net Services work?
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On the client side, ONS accepts requests from Oracle and translates them into the local network protocol (usually TCP/IP), and sents them across the network. On the server side, ONS receives the requres from the network, translates ito into an Oracle protocol and sends it to the database, where the listener process is waiting for requests to respond to as needed.
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What details must ONS know about the database and where is this information stored?
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Which computer contains it, what it's name is and to which port number its listener process is tuned. This information is stored in the service name, which is defined on both client and server, in the tnsnames.ora file.
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If using tools on the same computer where the database is running, what method besides ONS may be used to connect?
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a bequeath protocol
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Name three methods of reaching the database server from a client computer.
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-Client with Oracle Net
-Client with JDBC driver -Terminal with direct connection (bequeath protocol) |
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If you omit the service name during login, what happens?
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You reach the default database on your computer
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Name 5 network naming methods
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-Local naming
-Directory naming -Host naming -External naming -Easy connect |
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Which network naming method is the default method for connecting to a database?
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Local Naming (TNS)
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Which network naming method uses a configuration file to define connection to the database?
What is the name and location of the file? |
Local Naming (TNS)
tnsnames.ora, located in ORACLE_HOME/network/admin |
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Which network naming method uses a LDAP server to define connection to the database?
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Directory naming
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What does TNS stand for?
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Transparent Network Substrate
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Which network naming method uses tnsnames.ora?
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Local Naming
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What does LDAP stand for?
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Lightweight Directory Access Protocol
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What is LDAP?
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Stores names and their mappings, much like a DNS server
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Which network naming method uses IP address?
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Host naming
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Which network naming method uses third-party software applications to provide naming service?
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External naming
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Which network naming method uses no naming, but rather a direct connection string?
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Easy connect
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What is the most commonly used network naming method?
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local naming with TNS names
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What is the function of the listener?
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- listens for requests made by user connections
- allocates a server process (directly for dedicated servers, or indirectly using a dispatcher process for shared servers) |
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how to start, stop and check the status of the listener process in Unix?
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lsnrctl start
lsnrctl stop lsnrctl status |
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What is the default setting for listener logging and tracing, and why?
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Both default to OFF, because both can be a drain on resources.
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What command calls a utilty which validates TNS configuration?
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tnsping
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what background process distributes connections from user sessions to server processes in a shared server configuration?
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Dnnn - Dispatcher process
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Which server configuration uses CPU and memory more efficiently?
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shared server
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Which server configuration is best for an OLTP system with a large number of users (>1000 users)
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shared server
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Which server configuration is best for a system with large amounts of memory and CPU power and why?
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dedicated server, because users will never have to wait for a server process to be available
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define connection
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the link from a user session, through the server session and to the database
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How do you define whether a user connection is dedicated or shared?
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in the tnsnames.ora file
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PMON definition and function
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Process Monitor process cleans up after user sessions are finished, and monitors server and user sessions and tries to restart them if they have stopped unexpectedly
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DBWn definition and function
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Database Writer process writes modified buffers to datafiles.
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How many Database Writer processes are configured to start up as defaults?
What are their names? Why would more be configured? |
Two
DBW0 and DBW1 to speed up performance if your system is very active |
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LGWR definition and function
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Log Writer process writes redo log buffers to the redo log files
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When does LGWR act?
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-every 3 seconds
-when the redo log buffer is 1/3 full -immediately before DBWn process writes |
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What is the sequence of LGWR writes to multiple redo log files in a group?
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they are written in parallel, at the same time
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CKPT definition and function
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Checkpoint process signals DBWn to begin writing to disk by issuing a checkpoint
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Does CKPT write any data to disks?
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No
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SCN definition and function?
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System Change Number identifies changes, such as updates and checkpoints. It is written into each redo log entry, the control files and each data block that is written back to the datafiles.
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SMON definition and function
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System Monitor process handles recovery if it is needed. It also cleans up unneeded temporary tables and restores blocks that are released to make them available for use.
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ARCn definition and function
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Archiver process (only present when db is in ARCHIVELOG mode). copies redo log files to separate location outside the database, into archive redo log files.
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How many Archiver processes are configured to start up as defaults?
What are their names? How many Archiver processes can be configured? |
Two
ARC0 and ARC1 Ten (ARC0 through ARC9) |
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Dnnn definition and function
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Dispatcher process, (only present in shared server mode), distributes user connection requests between server processes
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What are the two main sections of memory for the Oracle instance?
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- System Global Area SGA)
- Program Global Area (PGA) |
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How many redo log groups are recommended?
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Three
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With two redo log groups, each with two members, explain how LGWR and ARCn work in a database in ARCHIVELOG mode
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With Group1 active, LGWR writes to both members in Group1 in parallel. When the members fill up, log switch occurs for LGWR to write to Group2, and ARCn copies from one member of Group1 to an archive redo log file. Once Group2 is full and ARCn is done copying from Group1, a log switch takes LGWR back to Group1 to overwrite the previous data with new data.
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How large are redo log files by default?
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50 MB
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Redo log file sizes should be adjusted to get approximately what frequency of log switching?
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4 times per hour
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What happens if the redo log file size is too small?
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log switches occur too frequently, causing overwriting too quickly (not enough info is available in the redo log files)
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What happens if the redo log file size is too large?
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Not enough log switches, makes for cumbersome recovery from redo log files
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How is the buffer cache used?
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As data is read from file, it is stored in memory in the buffer cache. When the same data is needed again, if it is already in the buffer cache, the server process reads the block from the buffer, which is much faster than reading from disk. If not, it reads the block from disk to the buffer, and then uses the block.
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What are the possible sizes for the buffer cache and what is the default size?
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2K, 4K, 8K, 16K and 32K.
Default is 8K. |
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What are the memory components within the SGA?
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- Buffer cache
- Shared pool - Redo log buffer - Large pool - Java pool - Streams pool |
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How is the shared pool used?
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When a server process sends a request, such as a query, parsed SQL is stored in memory in the library cache section of the shared pool The results of the parsing and the results of the Optimizer's path selection process are stored in the shared pool. When new requests come in, Oracle reuses old requests if possible, to save time. It also has a metadata cache.
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What are the parts of the shared pool?
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library cache
metadata cache (row cache) |
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When a change is made to data, what is stored in the redo log buffer?
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copy of the changed data and a copy of the original data
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What Unix command can be used to see if the Database Control is running?
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ps -ef grep | oracle
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What four main tabs are available in the top left in the database control interface?
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