i m working on oracle 10g using db_block_buffers. But i m not able to get information from database cache advice. Is there any method or procedure to activate cache advice despite of db_block_buffers use?
i have a application which uses 32 tables for retrieval in this 4 tables are important and have a size more than 100 mb can i move the index of these 4 tables cache memory to improve the applications retrieval performance if i done so ,then that will affect any other applications performance
If I have NO datafiles other than of the default block size, would I need to define a size for those other buffer pool? Is there any process that would benifit of these pools?
At a customers site I see lot of long lasting library cache locks during a complex ETL run. Several Sessions run in parallel and create Database tables with dynamic sql ( CREATE TABLE AS SELECT ....) .
Sometimes these procedures wait for each other with wait event 'Library Cache' . I presume that this is a side effect of the dynamic DDL in the stored procedures. Is that possible even when the Procs create different Tables but reference the same tables in their SELECT clauses ?
I presume that this is plausible but I need some arguments to convince my colleagues.
Design stage of New SAN. I can put a lot of the database, including redo on SSD.
1. Hardware sub tiering enabled. Has anyone ever gauged performance with enabling 11g Smart flash cache using the SSD as the flash device even with the hardware subtiering on? ie, if the hardware subtiering is moving hotblocks to most performant disk, is there much significant benefit having the flash cache on. Im guessing yes as the flash cache is working at the SGA level.
2. To redo or not to redo on SSD. Many notes say not to so as to avoid log file sync waits. Is there a way to keep it on the SSD and avoid the waits? Is there any risk of enhanced degradation of the disks over time with having so much sequential writes from the redo if I leave it on there?
How to Minimise Waits for 'Log File Sync' [ID 857576.1] (discusses keeping redo off ssd but only generally)
I have an application built in Apex 4.2It's been running fine for several weeksI've not made any changes to the codeSuddenly it developed what seems to be a cache problem.If I enter a search criteria; it displays results. I enter a different search criteria and it brings back the same results as the first criteria.I enter a search criteria in a different field and I still get the results from the first searchI go from Internet Explorer to Mozilla.
DIfferent search criteria, but same issue. Google chrome - same issueThe obvious answer is to clear the cache.I have a process set up that is clear Cache for Items , on submit after computations and validations and then I list all the items individually.This process has been there all along.
I never had this problem before.If I log out and come back in, same issue. What ever I enter as the first search criteria is the results no matter how I search
Considering the below factors, I am planning to increase the buffer cache value from 256Mb to 512Mb.
1. Buffer cache hit ratio value is around 35% even in the normal period. 2. free buffer requested value is below during peak & normal hours below.
Statistic Total per Second per Trans --------------------------------- ------------------ -------------- ------------ free buffer requested 54,694,995 15,226.9 2,523.7 free buffer requested 23,412,674 6,501.7 2,585.9
3. most of the top 5 physical reads & logical reads queries are well tuned and some of queries are doing FTS on small tables (table count min 1500 max 35000). SO indexing option is not required for these queires. But these queries getting executed frequently.
SQL> show sga
Total System Global Area 2148534928 bytes Fixed Size 731792 bytes Variable Size 1879048192 bytes Database Buffers 268435456 bytes Redo Buffers 319488 bytes
5.top 5 waitevents during db slow performance & high cpu utilization (>80%) issue.
Top 5 Timed Events ~~~~~~~~~~~~~~~~~~ % Total Event Waits Time (s) Ela Time -------------------------------------------- ------------ ----------- -------- latch free 1,848,898 153,793 52.00 buffer busy waits 395,280 87,201 29.49 db file scattered read 3,488,648 34,199 11.56 enqueue 4,052 10,897 3.68 CPU time 5,567 1.88
6. Top 5 waitvents during normal activities and CPU utilization is around 40%.
Top 5 Timed Events ~~~~~~~~~~~~~~~~~~ % Total Event Waits Time (s) Ela Time -------------------------------------------- ------------ ----------- -------- CPU time 1,860 45.32 db file scattered read 1,133,669 985 23.99 imm op 776 605 14.73 sbtinfo2 208 139 3.40 sbtbackup 2 123 3.00
1) Is shutting down the DB flush all the data buffers, from the buffer Cache? 2) In any oracle version, do we have any way to flush only the buffer Cache.
1)If i issue a DELETE statement to delete a row, will this statement drag any data from the datafile to database buffer? How is the change made by a DELETE statement recorded in buffer cache? How is this change then applied to the data in datafiles after commit?
I have some confusion about Keep Pool in Buffer Cache.
1. What is the reasoning for placing a table in the KEEP buffer pool because if it is frequently accessed, it will be around when needed (ie if it is constantly being accessed it will not age out) . 2. Would the table be still in the Default Pool if the Keep Pool is not sized and the command is being issued alter TABLE SCOTT.EMP storage (buffer_pool keep) ? 3. If the database is restarted will the table be wiped out of the Keep Pool and again be pinned to the Keep Pool ?
i have created form with table page to enter hotel details there is on 6 check box which are not database column .i have create these check box to keep days details when hotel give service .so i have use
these 6 check box are used Source used :Only when curren value in session state is nullSource Type : Static Assignment (Value equals source attibute) Problem are when i create new record then these 6 check box are not clear cache and when i update any record value are not clear cache . i need when i create or update recor then all 6 check box should be null after keep recor.