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
View 1 RepliesWhat is the difference between cache fusion and Cache Coherency. Both are same or different functionality.
View 1 Replies View RelatedI have some question.
TTversion : TimesTen Release 11.2.2.3.0 (64 bit Linux/x86_64) (tt112230:53376) 2012-05-24T09:20:08Z
We are testing a AWT cache group ( with CacheAwtParallelism=4 ).
Application(1 process) to the DML generates to TimesTen(DSN=TEST).
At this point, Are delivered to the 4 parallel DML?
[TEST]
Driver=/home/TimesTen/tt112230/lib/libtten.so
DataStore=/home/TimesTen/DataStore/TEST/test
PermSize=1024
TempSize=512
PLSQL=1
[code].......
I am on 11.2.0.3 Enterprise Edition. We are using the new feature "Composite Domain Index" for a Domain index on a very large table (>250.000.000 rows). It really works with mixed queries. We added two number columns using FILTER BY.We have lots of DML on this table. Therefore, we are executing synchronize and optimize once the week. The synch behaves pretty normal. But "optimize_index" takes a very very long time to complete. I have switsched on 'logging' for the optimize process. The $I table takes some time but is finished normally. But the optimization of the $S table (that is the table created for the CDI feature) is running over 12 hours now - and far from being finished. From the logfile, I can see that it optimizes 1000 rows every 20 minutes. Here is the output of the logfile:
Oracle Text, 11.2.0.3.0
14:33:05 06/26/12 begin logging
14:33:05 06/26/12 event
14:33:05 06/26/12 process $N for optimize: SEQDEV.GEN_GES_DESCRIPTION_CTX_I
14:33:16 06/26/12
14:33:16 06/26/12
[code]....
I haven't found a recommendation from Oracle not to use "optimize_index" for Domain Indexes with CDI. But in my case, it would be much faster just to drop and recreate the Domain Index in question.
I have a huge table (about 60 gb) partition over range. The index on this table is global index created on 4 columns together. I have a query which is running very slowly. The explain plan is showing the use of this global index.Explain plan is not showing pstart and pend because the index is global.
View 6 Replies View RelatedI have a global index and I want to convert it to local index.Is there a way to recreate local index with out dropping the global index.
I can create a local index first and then drop the global index. But is there a way to create it with out dropping the global index, just convert it.
I am facing the error "ORA-01502: index or partition of such index is in unusable state " while loading the text data using
sql loader with direct path (direct = Y ,rows = 10000) option. Table consists an composite non unique index. If I query the dba indexes for the effected index it shows the index status as VALID. There was no maintaince done on the effected table or index. I have tried loading the same data using conventional path but didn't found any issues for the same.
I have a query which had a join:
a.c1=b.c1 and a.c2=@var
where @var is user supplied input at runtime...We had a index on a.c2 . The CBO would use this index to generate an opitimised query plan.We found some records from table "b" were dropping due to inner join. So we made a change in join. It'd be like
a.c1(+)=b.c1 and nvl(a.c2,@var)=@var
This query is no longer using the index, instead its doing a full table scan causing the query to slowdown.I have tried creating index on nvl(a.c2,'31-dec-9999')
But the CBO won't use it.Anyway to create index on this col so that full table scan can be avoided?
How to force an index if the table not using the index?
View 10 Replies View RelatedWe have occurrences of enq : TX - index contentions in the database. Using the SQL ID, we have identified the INSERT statement and the table which they are trying to insert.
This table has almost 25 different indexes, some of which are unique as well.I am wondering how to identify the actual index causing issue, out of these 25 indexes.
Is there any way to pin point to the name of index which is causing the lock?My plan is, once the index is identified, I would like to check the extents and inittrans and other attributes of this index to fix.
Can we create non-cluster index on a clustered index?
View 5 Replies View RelatedAre there any recommendations or good practices to set sequence CACHE parameter (for example one caching per hour, day etc)?
View 4 Replies View RelatedI have a query - whch used to be run in 30 minutes and now hangs on for hours and not finishing. The wait i see is
wait event latch: cache buffers chains.
This is a 11.1.0.7 2 Node RAC environment runing on HP-UX Itanium.
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?
View 2 Replies View RelatedWhat is cache/no cache & cycle/no cycle in Sequence?what is the use?
View 3 Replies View Relatedhow can we check the size of data buffer cache.
View 7 Replies View Relatedwhat will be best buffer cache hit ratio for a database for good performance
note : in general
In Oracle 9i
I know that db_block_size defines the standard/default block size for my datafiles.
I know db_cache_size defines the size of the my default database buffer of the size of my standard/default block size.
db_block_size = 8192 (8k)
db_cache_size = 200Mo of 8k block
Is there any needs for the other buffer cache
db_16k_cache_size
db_4k_cache_size
db_32k_cache_size
and so on?
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?
I want to know what exact process happens in oracle architecture when an update query is fired.
View 1 Replies View Relatedunderstand the metric Row Cache Hit Ratio in V$SYSMETRIC_HISTORY? Is it the dictionary cache hit ratio?
View 1 Replies View RelatedAt 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.
11.2.0.2.0
OEL.
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)
[URL]
Is db_cache_advice = ON still necessary when sga_target is set?
View 2 Replies View RelatedI 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
Any on give explanation for difference between Index and Clustered Index?
It will be great if i get explanation how memory allocation and Execution takes place.?
give a script to find how much my db buffe cache and redo log buffer cache is used and how much is free.
View 1 Replies View RelatedDatabase : 9.2.0.7
Os : windows 2003 sevrer standdard edition
RAM 4 Gigs
The buffer cache hit ratio in this server is around 83%, where it normaly was around 98% before i did some maintenance activities.
I have done some maintenance activities in January on this database.
Maintenance activties includes below steps
1.In production i have deleted old data in the production tables
2.Reorganized tablespaces,tables
3.Rebuild indexes for those tables.
4. At last collected statistics for those tables.
Now after this activity the buffer cache hit ratio is very low.
How to move a partition of a table to db_keep_cache ?
View 8 Replies View RelatedConsidering 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.