If the STREAMS_POOL_SIZE initialization parameter also is set to a nonzero value, then Automatic Shared Memory Management uses this value as a minimum for the Streams Dec 8, 2014 · It depends. (Our SGA_MAX_SIZE =SGA_TARGET) Is there ant restriction with SGA_TARGET size with 64 bit system as 4GB with 32bit. As this area is in the DB_BLOCK_BUFFERS is one of several parameters that contribute to the total memory requirements of the SGA of an instance. 3. May 22, 2007 · Increase the Oracle SGA_MAX_SIZE setting in your pfile that you created from your spfile. 78 db_cache_size db_cache_size specifies the size of the default buffer pool for buffers with the primary block size (the. It’s a static parameter and database must be restarted to take effect of this parameter. answered Dec 5, 2012 at 5:28. This article presents the methods necessary to create very large buffer caches Aug 6, 2020 · Memory for the buffer cache is allocated at the stage of starting the database instance. DB_CACHE_SIZE Nov 19, 2015 · The solution is to "consider making the log buffer bigger if it is small. You must have an Oracle login with DBA privileges to use these advisors and to perform the following tasks. DB_KEEP_CACHE_SIZE is the parameter which determines the size of the Keep Buffer Pool. OBJECT_CACHE_OPTIMAL_SIZE specifies (in bytes) the size to which the session object cache is Feb 11, 2016 · I have an Oracle 11. value + con Feb 21, 2022 · Buffer Cache: The database buffer cache is the largest memory area in the SGA. Apr 18, 2011 · 1) not necessarily, as the buffer cache size increases, the number of cache buffer chains latches we use increase. Especially if you don't make use of bind variables. Since the log buffer is flushed: Sep 11, 2004 · You would use the db cache advisor (in a statspack report, via a v$ view or by using OEM) to see if any benefit can be had from increasing the size of your buffer cache (after tuning your queries of course). On 32-bit Linux the total SGA size is limited to around 2Gig. For more information on the engine element, refer to Section 8. 9. PGA_AGGREGATE_LIMIT: The maximum PGA size for the PDB. !Buffer Cache Hit Ratio : 81. For many types of operations, Oracle uses the buffer cache to store blocks read from disk. This memory area stores the copies of the data blocks that are read from the database discs. 1) direct path read, 2) conventional path read using the buffer cache - but only using a small portion of it (since we cannot cache the entire table anyway) and 3) by a conventional path read into the buffer cache but attempting to cache everything we can (by getting rid of the other stuff in the cache) Jan 19, 2017 · I want to ensure that all cached items are cleared before running each query in order to prevent misleading performance results. Jan 22, 2018 · By default there is 1 database writer process available for each database : We can increase no of writer process using db_writer_processes parameter . SQL> show sga. Buffer Cache (SGA) This is the most important cache, it contains blocks of tables, indexes, and other objects. Whenever you query a table, data is read from the data files in the units called blocks. This post has been answered by Mark D Powell on Jul 27 2018. The maxEngine value sets the maximum number of processes ready to respond to user requests for running reports. This parameter, together with DB_BLOCK_SIZE, determines the total size of the buffer cache. The UNIX buffer cache consumes operating system memory resources. How must we do this? By increasing memory_target and letting Oracle grab more memory for the buffer cache? Or by explicitly setting a value for db_cache_size (which now is zero)? You can set the value for db_cache_size Mar 12, 2013 · Oracle 9i reintroduced a mechanism of estimating the impact of increasing or decreasing the database buffer cache size using a new initialization parameter, DB_CACHE_ADVICE. May 30, 2013 · Buffer cache is the area of memory used to hold the blocks of data read from and written to data files. So, as you increased the size of the buffer cache, you made finding a block in the buffer cache "take longer" quite possibly, hence latch holders were taking a little longer and everyone else 24. Jun 29, 2016 · 4. If SGA_TARGET is set: If the parameter is not specified, then the default is 0 (internally determined by the Oracle Database). 2 and later Oracle Database Cloud Schema Service - Version N/A and later Oracle Database Exadata Cloud Machine - Version N/A and later Jan 12, 2011 · Increasing db_cache_size. 1 or ramfs in RHEL 3-5. sum ( *_pool_size ) + log_buffers) /. For transaction-based workloads, Oracle database blocks are normally loaded into a dedicated shared memory area in main memory called the system global area (SGA). Dec 16, 2023 · but you are missing the point the buffer cache is never read only. For tuning the LOG buffer, we have some tips: Increase the Size of Log Buffer. When we need a block - we take the DBA of the block (data block address) and hash it to a number between 1 Aug 1, 2021 · If both the STREAMS_POOL_SIZE and the SGA_TARGET initialization parameters are set to 0 (zero), then, by default, the first use of Streams in a database transfers an amount of memory equal to 10% of the shared pool from the buffer cache to the Streams pool. Release 19 database reference 1. 78 DB_CACHE_SIZE. Starting from version 10g – the cache buffer size can be changed both automatically (enable the automatic control mechanism) and manually. However, its only 268 MB in our database. Alternatively, you can set the value of the SGA_MAX_SIZE parameter to be larger than the sum of all of the SGA components, such as the buffer cache and the shared pool. Increase SGA_MAX_SIZE and SGA_TARGET. Keep Table in Buffer Pool To increase the amount of memory allocated to the buffer cache, increase the value of the DB_CACHE_SIZE initialization parameter. (Optional) Database Smart Flash Cache (flash cache) lets you use flash devices to increase the effective size of the buffer cache without adding more main memory. 4. The value of SGA_TARGET in the PDB must be less than or equal to the SGA_MAX_SIZE value at the CDB level. Prior to version 9i, you cannot resize the cache buffer without restarting the instance. Decreasing the Shared Pool memory size. Doing so enables you to dynamically increase a cache size without having to decrease the size of another cache. Click on any cell in the "Query Result" window to set the focus to that window. Total SGA Size (MB)39936. Applies to: Oracle Database - Enterprise Edition - Version 11. Checking the JAVA Pool size. SGA_MIN_SIZE: The minimum SGA size for the PDB. This advisory relies on an internal simulation based on the current workload to predict the cache "miss" rates for various sizes of the buffer cache ranging from 10% to 200% of the current cache size. When you are confident that your SQLs are well tuned, you can consider increasing buffer cache to improve performance. Effective use of the buffer cache can greatly reduce the I/O load on the database. value / (cur. Source. At the time of writing, Automatic Memory Management (AMM) is only supported on the major platforms (Linux, Solaris, Windows, HP-UX, AIX). DB_BLOCK_SIZE can be specified only when the When the streams pool is created, the required SGA memory is taken from memory allocated to the buffer cache, reducing the size of the cache to less than what was specified by the DB_CACHE_SIZE initialization parameter. 6157. 0 . Subsequent passes let you make adjustments in earlier steps, based on changes in later steps. Oracle Database 11g introduces exciting new HA functionality and enhances many of the existing features for scalability and performance. Afzal Sep 23 2010 — edited Sep 23 2010. com. The SGA of an Oracle database contains memory pools that are used by the database to accelerate May 6, 2021 · Tune log buffer space or log file sequential read waits in Oracle. 0. It might be necessary to repeat the steps of memory allocation after the initial pass through the process. To create and use tablespaces with block sizes other than the database's standard block sizes (such as for Compressed data in a database block is self-contained, which means that all information needed to re-create the uncompressed data in a block is available within the block. also the parameters like db_cache_size, shared_pool_size were set to 0 (before and after the sga scale up)to enable automatic memory tuning. 0 RACed database on Compaq TRU64 Unix: Reduced db_cache_size from 1008M to 608M: alter system set db_cache_size = 629145600 scope=both sid='dbx2'; The db_cache_size did get reduced, but I did not see any memory freed to the o/s - does thit not happen instantaneously ?? 10-02-2002 Jun 12, 2014 · GETS: Show the total number of requests for information on the corresponding item; PINS: Show the number of executions of SQL statements or procedures; RELOADS: Show the number of times, during the execution phase, that the shared SQL area containing the parsed representation of the statement is aged out of the library cache to make room for another statement. I clear out the shared pool (to get rid of cached SQL/explain plans) and buffer cache (to get rid of cached data) by running the following commands: alter system flush buffer_cache; alter system flush shared_pool; Jun 24, 2020 · This is about the db_block_size, db_16k_cache_size parameters. If Oracle has more objects to keep in the KEEP buffer, automatically it removes the older objects from the keep buffer. When the buffer fills up, it has to write Dec 4, 2012 · Increased buffer cache and worse performance; classic case of not tuned SQL applications that restricts scalability Check your SQLs and tuned them. 7. Now , lets change it to 3. May 29, 2019 · If DB_KEEP_CACHE_SIZE is not used then no Keep buffer is created. So keeping the log buffer size small, say 128K, is beneficial. Share. Despite this, according to the following MOS note the only SGA memory sizing parameter that Oracle recommends setting at the PDB level is SGA . Dec 8, 2014 · It depends. Configuring and Using the Buffer Cache. Alter system flush buffer_cache global; Then the two database initialization parameters Each non-default block size has its own pool. ORACLE-BASE - DBA Scripts: db_cache_advice. Tune the indexes to reduce the I/O and reduce the number of blocks that need to be in the buffer cache. 2) ASM would not be slow there - once the data is on disk - ASM is really out of the way. . DB_CACHE_SIZE specifies the size of the DEFAULT buffer pool for buffers with the primary block size (the block size defined by the DB_BLOCK_SIZE initialization parameter). backup management system, is up to 25%. There's no single query to display them all. The size of a granule is determined by the size of your SGA (this sounds recursive to a degree, as the size of the SGA is dependent on the granule size). The size of the buffers in the KEEP buffer pool is the primary block size (the block size defined by the DB_BLOCK_SIZE initialization parameter). Compressed data in a database block is self-contained, which means that all information needed to re-create the uncompressed data in a block is available within the block. Jun 2, 2008 · 1) typically - yes, in order to do a consistent get, the logic is typically: a) go to buffer cache and look for block. A very large log_buffer can have an adverse affect as waits will be longer when flushes occur. Buffer Cache 29952. Nov 20, 2022 · Increase the buffer cache size to accommodate more buffers. Here is a query to get your database's current hit ratio: SQL> -- Get initial Buffer Hit Ratio reading SQL> SELECT ROUND((1-(phy. Mar 11, 2009 · I' trying to increase the sga to utilize the more than 4GB of memory, but because my system is 32-bit so I have to use the (use_indirect_data_buffers) parameter with db_block_buffers and but 0 in db_cache_size. As a result, the following parameters are automatically sized: SGA_TARGET. When you start the database - it is EMPTY, it needs to get filled (modified, written to, changed) As your progress over the course of the day, you'll have physical IO's (unavoidable). In this way lgwr will write the same data to disk many times. AMM Configuration. Typically, these will allow free memory pages to be used to cache I/O. Scheduling the jobs to run. db_cache_size big integer 1008M. But the algorithms surrounding the size and persistence Mar 30, 2009 · To keep these warm segments blocks cached, you could do one of the following: * Assign these segments to the keep pool, in an attempt to let the warm blocks stay in the buffer cache longer. Steps to configure keep cache in Oracle: STEP 1: Check the current keep cache size: SQL> show parameter keep; STEP 2: Check table size : If keep cache is not configured or not sufficient to hold the entire table, then increase the size of the cache but before that check the size Dec 15, 2012 · BUFFER BUSY WAITS. Hi all. they advise: "Ensure that the log_buffer is not too big. SGA_TARGET: The maximum SGA size for the PDB. To create and use tablespaces with block sizes other than the database's standard block sizes (such as for Oracle 11g takes this one step further by allowing you to allocate one chunk of memory, which Oracle uses to dynamically manage both the SGA and PGA. Oracle offers a comprehensive and fully integrated stack of cloud applications and platform services. I can get java,shared and large pool's values from sgastat view, but not buffer cache's value. Feb 1, 2022 · Severe Performance Problems Due to Sudden drop/resize/shrink of buffer cache (Doc ID 1344228. Oct 7, 2015 · 3. 1) direct path read, 2) conventional path read using the buffer cache - but only using a small portion of it (since we cannot cache the entire table anyway) and 3) by a conventional path read into the buffer cache but attempting to cache everything we can (by getting rid of the other stuff in the cache) If they are set, the setting db_cache_size acts as a lower limit. Analyze other details from command to gain insights into various SGA components. Feb 24, 2001 · when you use AMM, the shared_pool_size is a lower bound for the size of the shared pool (your shared pool will never go below 400mb) - and the upper bound would be limited by the sga/memory_target setting coupled with any other cache sizes you put a lower bound on. This is a dynamic parameter that can take the values OFF (the default, meaning the buffer cache advisory is turned off and no memory is allocated to it), ON (meaning the Checking the Redo Log buffer size. To increase the amount of memory allocated to the buffer cache, increase the value of the DB_CACHE_SIZE initialization parameter. b) if block is not there, perform physical IO and put it into the cache. The dedicated server reads from disk. to increase the effective size of the Oracle database buffer cache without adding more main memory. ALTER SYSTEM SET shared_pool_size=60M Mar 10, 2014 · But the problem is, i'm working on a database that has ASMM(Automatic Shared Memory Management) which means SGA size is automatically controlled(so it's components values are changing). shared pool = 400mb. , 39936. Also is there any way to to check dirty buffers%. Articles Oracle 8i Oracle 9i Oracle 10g Oracle 11g Oracle 12c Oracle 13c Oracle 18c Oracle 19c Oracle 21c Oracle 23ai Miscellaneous PL/SQL SQL Oracle RAC Oracle Apps WebLogic Linux MySQL Dec 14, 2011 · I mentioned in my post , OS is RHEL4 and Oracle 11G 11. I want to increase the size of the parameter db_cache_size from 1008M to. The shared pool works best when right sized to hold what you do. SGA ComponentCurrent Allocation (MB) Shared Pool 9216 -->>>>> I want to increase this value to 11GB (At the moment its 23. Oracle 8i Oracle 9i Oracle 10g Oracle 11g Oracle 12c Oracle 13c Oracle Put_Line('Increase SHARED_POOL_SIZE parameter DB Block Buffer Cache 1. Total System Global Area 2147483648 bytes. This cache contains the shared SQL and PL/SQL areas and control structures such as locks and library cache handles. If this parameter is 0, Oracle adjust automatically size. You can set this parameter only when DB_BLOCK_SIZE has a value other than nK. Flash cache can improve database performance by Dec 22, 2014 · It depends. DB_KEEP_CACHE_SIZE specifies the size of the KEEP buffer pool. There are several ways to allocate more memory than this, but the most robust and scalable method requires the use of a shared memory file, like shmfs in RHEL 2. The buffer cache is a data structure, a shared data structure. Generally, the most active and most recently used objects will be in the buffer cache. Please comment. I found when I set the trace on, this problem was gone, and after I set the trace off, it came back again. for example, if you say. AMM Parameters. ~Library Cache Miss Ratio : 0. So i need instant values of this components. The value of SGA_TARGET in the PDB must be twice the PDB’s DB_CACHE_SIZE value, if the PDB’s DB_CACHE_SIZE value is set. In order to obtain the optimum size for each of these subcaches as well as the database buffer cache, the performance advisors in Oracle 11g Enterprise Manager can be used as well 1. Tune the SQL statements that are causing contention for the buffers. DB_BLOCK_BUFFERS is one of several parameters that contribute to the total memory requirements of the SGA of an instance. Hi All, I want to check the Buffer cache size used and free, while running the process. Your shared pool is somewhere between 25 and 100 meg or so. The DB_CACHE_SIZE parameter specifies the size of the default cache for the database's standard block size. " However, if we set it too "big" it can also result in performance problems. Accepting the report request from various clients. we can see it have default value 1. ~Database Up Since : 09:56:23 AM, September 23 2010. I am not sure if setting the trace on increases buffer size automatically or not, but I want to start from here. Increasing the Buffer Cache memory size. DB_BLOCK_SIZE can be specified only when the Jun 23, 2000 · To approximate the size of the SGA (Shared Global Area), use the following formula: ( (db_block_buffers * block size) +. For example, if DB_BLOCK_SIZE=4096, then it is illegal to specify the On the server, it is used to cache frequently used objects requested as a result of client requests to help in performance. Allocating additional memory to the Oracle database can improve performance by enabling more local reads. This means that if the buffer cache was configured with only the minimal required SGA, then Data Pump operations may not work Sep 4, 2008 · You will basically setup a buffer cache (you size it, it'll be done in granules - 4, 8, 16m granules. Oct 11, 2018 · The advisor views indicate that increasing the buffer cache by 4 GB will half the physical reads, and we have 4 GB to give. The library cache is a shared pool memory structure that stores executable SQL and PL/SQL code. New comments cannot be posted to this locked post. c) return block from cache. A block is also compressed in the buffer cache. 1% of the total size of SGA,i. which should be 321 MB here. To do it, follow these 4 steps: Connect to the Oracle database with SQL*Plus or Enterprise Manager. Buffer Cache is an other name for logical oracle RAM buffer and is a part of the in System Global Area (SGA) . 1 and up only) The division by . This is the second wait event which is encountered in case of logical I/O. System altered. Dec 7, 2010 · On restarting the instance we found that Oracle increased the value of buffer_cache (compared to previous value) & decreased the value of shared_pool (compared to previous value). sort_area_size 2000000. Run SHOW SGA. Oct 2, 2002 · Posts. On standard unix databases, the data is read from disk into the unix buffer where it is then. Same with SGA memory. For more information about Oracle (NYSE:ORCL), visit oracle. 1) Last updated on FEBRUARY 01, 2022. sga_target = 1000M db_cache_size = 400M Oracle 19c Database: Larger SGA. 18. For many types of operations, Oracle Database uses the buffer cache to store data blocks read from disk. 1) direct path read, 2) conventional path read using the buffer cache - but only using a small portion of it (since we cannot cache the entire table anyway) and 3) by a conventional path read into the buffer cache but attempting to cache everything we can (by getting rid of the other stuff in the cache) How to increase db_cache_size in oracle. The keep/recycle pools are rather sophisticated tuning devices that more systems would not overly benefit from. 1 Buffer Cache Limits. You can check the Streams_pool_size , SGA and Shared_pool as follows. e. We have three basic ways to accomplish reading this table. sort_area_retained_size 2000000. The first 50 rows will be fetched into the "Query Result" window. I executed the following command on our Oracle 9. Your log_buffer is generally 5meg or less. Many DBAs do their best to get a 99% or better buffer cache hit ratio, but quickly discover that the performance of their database isn't improving as the hit ratio gets better. Note that most of the queries Aug 6, 2018 · If I size the log_buffer to 5M, the system will write to disk when log_buffer is 1m full and again when the log buffer is 2m full or any commit happens or after 3 secs. database initialization parameter. A common "myth" (conventional wisdom) is that if you are getting ora-4031's due to not using bind variables you must immediately increase the size of the shared pool. The Smart Flash Cache feature allows you to expand the database buffer cache Jul 27, 2018 · How to check the Buffer Cache size. Table compression not only reduces the disk storage but also the memory usage, specifically the buffer cache requirements. Sep 2, 2004 · According to the metalink, increasing the buffer size may solve this problem. It displays info on System Global Area (SGA) size. How the Database Buffer works: Oracle9i includes a buffer cache advisory to aid configuration of the buffer cache. In a shared server architecture, the library cache also contains private SQL areas. —————————. Commands: SHOW PARAMETER. Your block buffer cache is generally many 10's to 100's of megs (or even in the gigs) in size. Oct 31, 2012 · Current Allocation. that way, the next person that wants it, will find it in the cache. To create and use tablespaces with block sizes other than the database's standard block sizes (such as for Mar 22, 2011 · Each buffer in the database buffer cache is equal in size to the size of an Oracle block which is determined by the db_block_size. ALTER SYSTEM SET db_cache_advice=ON; ALTER SYSTEM SET db_cache_size=80M. The value must be at least the size of one granule (smaller values are automatically rounded up to the granule size). Library Cache. Jun 18, 2002 · As you increase the size of the cache, you have more lists, but bigger lists too (you will not have 5 times as many lists with 5 times the buffer cache). where *_pool_size is the java_pool_size, large_pool_size, and shared_pool_size. 9 is used to take into account the variable We would like to show you a description here but the site won’t allow us. Oracle's Automatic Shared Memory Management feature manages the size of the Streams pool when the SGA_TARGET initialization parameter is set to a nonzero value. Oracle Secure Backup, a centralized tape. 1 database using dynamic memory allocation with parameter MEMORY_TARGET. Oracle Database bypasses the buffer cache for particular operations, such as sorting and parallel reads. Reduce redo generation of unneeded tables like Logs table. Conceptually, think of the buffer cache as a two dimensional structure, there is an array of lists - each list has a latch. When I decrease it with SCOPE=BOTH, the size of the SGA doesn't seem to decrease along with it. Oracle document says, Statement 1: DB_nK_CACHE_SIZE (where n = 2, 4, 8, 16, 32) specifies the size of the cache for the nK buffers. In AWR report, we are getting waits for log event. memory_target=0 DB_CACHE_ADVICE=ON client_result_cache_size big integer 0 db_16k_cache_size big integer 0 db_2k_cache_size big integer 0 db_32k_cache_size big integer 0 db_4k_cache_size big integer 0 db_8k_cache_size big integer 0 db_cache_size big integer 256M db_keep_cache_size RAC, Data Guard, RMAN, and Flashback are a few examples of HA features available in Oracle. For example, the PGA advisor would tell you "hey, if you increase the PGA target by X, then you would expect to see Y less sorts to disk". It is easy, but takes 3 steps: In sql developer, enter your query in the worksheet and highlight it, and press f9 to run it. Dec 14, 2010 · So, the fix? Increase your buffer cache size to make up for the loss of that OS secondary SGA - this will result in even faster performance as we won't have to go to that secondary sga, we just get it from the real one. 9, "engine". It specifies the *minimum* size that the db cache is allowed to be. No matter how easy it is, I really didn't change Sep 27, 2016 · Keep Buffer is also working in First In First Out mode. Does it need to be increased. * Assign the 'do not care to cache' segments to the recycle pool, keeping the recycle pool fairly small so as to let the blocks come into the cache and Oct 12, 2007 · 1) you would use the memory advisors (part of enterprise manager) or use statspack itself. increase the SGA_TARGET size to other 3 GB where 1 GB is allocated to the shared pool and 2 GB for the buffer cache. 1. SGA_MAX_SIZE. A value of zero is illegal because zero is the size of How to increase oracle buffer cache. May 1, 2023 · My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts. Review output for “Total System Global Area” line. Increase the degree of parallelism. Automatic Shared Memory ManagementEnabled. For example: sga_target = 1000M means I'll share out that 1000M, and if I need (say) more shared pool, the database can shrink the buffer cache down to whatever it wants to meet that need. The requested data is not returned straight to the user process, instead it is copied to the buffer cache, and then is read from the buffers in the By setting these two parameters to non-zero values, Oracle enables Automatic Memory Management, and tunes to the target memory size, redistributing memory as needed between system global area (SGA) and the instance program global area (PGA). STREAMS_POOL_SIZE. It is as i said. Oracle has many different types of caches. The “buffer cache”: Sep 23, 2010 · how to increase !Buffer Cache Hit Ratio. Buffer busy waits are there when latch is obtained on the hash bucket but the buffer is “busy” as. PGA_AGGREGATE_TARGET: The target PGA size for the PDB. For example, decreasing the size of the buffer cache lets you increase the size of another memory structure, such as the shared pool. Then in SQL*Plus start up the database using that pfile as follows. Pro*C/C++ Programmer's Guide and Oracle Call Interface Programmer's Guide for information on precompiler use of the object cache. Is there any adverse impact on database when we increase size of SGA_TARGET Oct 24, 2001 · It is true that the log_buffer is trivial in size compared to the rest of the sga. Hold the Ctrl key and tap the "A" key. Oracle Database manages the blocks in these pools in the same way as in the default pool. In this best practice the System Global Area (SGA) size is adjusted per the recommendation of the AWR report. It is a wait event for a buffer that is being used in an unsharable way or is being read into the buffer cache. It is easy, but takes 3 steps: In SQL Developer, enter your query in the "Worksheet" and highlight it, and press F9 to run it. my database performance is low how to increase Buffer Cache Hit Ratio. It shows you what would happen if you increase a memory region. SQL> show parameter db_cache_size; NAME TYPE VALUE. 03. sql : Oracle database SQL scripts. It shows SGA size. Oracle Databaseには、特定のバッファ・プールに割り当てられていないオブジェクトのために、DEFAULTバッファ・プールがあります。デフォルト・バッファ・プールのサイズは、DB_CACHE_SIZE初期化パラメータによって決まります。各バッファ・プールでは、同じLRU Mar 9, 2016 · @a_horse_with_no_name It depends on what you do with the DB: A separate single instance Oracle Database can be installed and used as an infrastructure repository for RMAN, Oracle Enterprise Manager Cloud Control, Automatic Workload Repository (AWR) Warehouse, Global Data Services Catalog, and Grid Infrastructure Management Repository without 9. 2048M in order to get better hit ratio. Monitor and Kill the sessions that hold the buffer lock for too long. Database Version : 8. 89 DB_KEEP_CACHE_SIZE. 4 Tuning Reports Server Configuration. 316. Db_nk_cache_size (where n = 2, 4, 8, 16, 32) specifies. I think shared pool should be sga_max_size - dba_cache_size - large_pool_size - java_pool_size. Although in some versions of UNIX, the UNIX buffer cache may be allocated a set amount of memory, it is common today for more sophisticated memory management mechanisms to be used. There are many ways to determine optimal memory settings, but the preferred way is to use memory advisors, including Memory Advisor, SGA Advisor, Shared Pool Advisor, Buffer Cache Advisor, and PGA Advisor. Nov 30, 2006 · definitely. Mar 6, 2002 · shared_pool_size 268435456. (java_pool_size is for 8. java_pool_size 33554432. 2. 2. Large SGA On Linux. Increase the Archive Process for faster writing. Improve this answer. rpxgvlwrvgtysjzkfoso