SQL 2012 :: Value Of Buffer Cache Hit Ratio
Jul 16, 2015What is better values for Buffer Cache Hot Ratio in SQL Server 2012. Is the values changed from 2008r2 to 2012?
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SQL 2012 :: DB Engine Page Life Expectancy And Buffer Cache Hit Ratio Is Too Low
Sep 12, 2014Our server administrator forwarded some messages from SCOM that indicate:
SQL DB Engine 2012 Page Life Expectancy and Buffer Cache Hit Ratio is too low
When I logged into the offending server, I could not find anything in the SQL Log File that indicates this.
I was wondering how did SCOM identify this issue - where in SQL Server would this have been reported to SCOM?
Buffer Cache Hit Ratio...how To Measure?
Jan 2, 2004Does anyone know how to measure the buffer cache hit ratio? I have been reading a lot about it but can't find this measurement in Performance Monitor.
Thanks
100% Buffer Cache Hit Ratio Not Always Optimal?
Jun 19, 2008I am wondering if 100% buffer cache hit ratio is considered not good in general?
Are there instances that it is actually bad and can contribute to server performance degradation?
Any thoughts on the topic most welcome :)
--------------------
keeping it simple...
Troubleshooting SQL Buffer Cache Hit Ratio
Jul 23, 2005This issue just happen recently. The buffer cache ratio went from > 90%to 50% and has slowly been climbing back up over 8 hours or so. Itscurrently @ 76%. Is this something I should take action on immediately?It seems to be coming back to normal...
View 1 Replies View RelatedEstimation The Buffer Cache Hit Ratio
Sep 1, 2006HiI have trouble with MSSQL2000 SP4 (without any hotfixes). During last twoweeks it start works anormally. After last optimalization (about few monthsago) it works good (fast, without blocks). Its buffer cache hit ratio wasabout 99.7-99.8. Last day it starts work slow, there was many blocks anddedlocks. There are no any queries, jobs and applications was added. Nowbuffer cache hit ratio oscilate about 95-98. I try update statistics andreindex some hard used tables, but there is no effect or effect is weryshort (after few hours problem return).Mayby somene know what it could be?Is it possible to estimate how each table (using DBCC SHOW_STATISTICS orDBCC SHOWCONTIG or others) how the table affect on total buffer cache hitratio?Marek---www.programowanieobiektowe.pl
View 1 Replies View RelatedCache Hit Ratio Vs Buffered Cache Hit Ratio
Mar 13, 2003On Microsoft performance monitor, what is the difference between SQL Server Cache Manager: Cache Hit Ratio and SQL
Server Buffer Manager: Buffer Cache Hit Ratio? We have a production server where the buffer cache hit ratio is
consistently at 99%, which is normal. However, the cache hit ratio is 73%. What is the difference between the two
hit ratios, and why would we have such a significant difference between the two?
Any help or advice would be much appreciated.
SQL 2012 :: When Does Database Clear Buffer Cache
Sep 28, 2015We are troubleshooting a performance problem and the test result is slow the 1st time but the subsequent runs are faster.. Logging out of application and log back in ( connecting to a new database session) did not clear the buffer cache as I thought it would.. When does the database clear the buffer cache? Is it not per database session?
I can issue CHECKPOINT and then run DBCC DROPCLEANBUFFERS to clear the buffers in the disk. But since we are testing from the application,do we need to run these commands via application code to clear buffer/per database session OR can we run these commands from a management studio session?
SQL 2012 :: Buffer Cache Size Much Lower Than Max Memory Config And Low PLE?
May 22, 2014I have a virtual server (VMware ESX) with 64GB RAM running a single instance of SQL 2012 SP1. The max memory config is set to 59392 (58GB).
The Page Life Expectancy for this server has been averaging well under 10 mins for the last few days, according to our monitoring.
I have been checking the amount of data in the buffer cache periodically during the day with the below query, which seems to show that there is never more than about 10GB of data at any one time, frequently dropping below 5GB:
SELECT COUNT(*) AS BufferPages,
CONVERT(decimal(10, 2), COUNT(*) / 128.0) AS BufferMB
FROM sys.dm_os_buffer_descriptorsWhy would the amount of cached data be so low (and cause so much churn)?
I am aware that other things will require some of that memory (plan cache etc.) but with Max Mem of 58GB, I would expect there to be a much higher amount of actual cached data at any one time. I did the same checks on another VM with the same amount of RAM/Max Mem setting, and there was 50GB of data in the cache, with PLE measured in hours.
SQL 2012 :: Find Buffer Cache Usage By DB Objects Within Particular Database
Jun 22, 2015I am using SQL 2012 and I am trying to find buffer cache usage by DB objects within a particular DB.
I am running the following query
select
name as DB,
objname as db_object_name,
COUNT(name) as cache_page_count,
COUNT('x')*8.0/1024 as size_mb
[Code] ....
Following are the results:-
DB db_object_name cache_page_countsize_mb
TEST_DBNULL 428 3.34375
TEST_DBsysobjvalues 369 2.882812
TEST_DBsyscolpars 44 0.34375
TEST_DBsysssislog 38 0.296875
....
.....
Question- Why am I getting 428 pages for which there is no corresponding DB object? Why are so many pages present in sys.dm_os_buffer_descriptors but are missing from sys.allocation_units.
SQL 2012 :: Buffer Cache And PLE (Page Life Expectancy) Query
Aug 17, 2015I'm getting an alert which states that both my Buffer Cache Hit Ratio and PLE are low on one of my SQL Servers though I'm not sure how to correctly check this.
I ran:
SELECT object_name, counter_name, cntr_value
FROM sys.dm_os_performance_counters
WHERE [object_name] LIKE '%Buffer Manager%'
AND [counter_name] = 'Buffer cache hit ratio'
Which gives me the Buffer Cache Hit Ratio, cntr_Value of 9 though its constantly dipping between 3-3000 and is never steady and I'm unsure if this is normal.
I also ran:
SELECT object_name, counter_name, cntr_value
FROM sys.dm_os_performance_counters
WHERE [object_name] LIKE '%Buffer Manager%'
AND [counter_name] = 'Page life expectancy'
Which gives me the Page life expectancy of 209061.
If these values would cause concern and if this is a normal Buffer Cache Hit Ratio? It's constantly dropping from high or low from what I can see. These scripts were pulled from another forum and I'm assuming they're showing the correct values.
SQL2K - Clean Buffer Cache And Procedure Cache.
May 31, 2007Is there a way to drop clean buffers at the database level instead of the server/instance level like the undocumented €śDBCC FLUSHPROCINDB (@dbid)€??
Is there a workaround for €śdbo€? to be able to flush procedure and data cache without being elevated to €śsysadmin€? server role?
PS: I am aware of the sp_recompile option that can be used to invalidate cached execution plans.
Thx.
Cache Hit Ratio Over 100%
Sep 18, 2000I have been seeing this strange statistics in one of our servers. The cache hit ratio has gone beyond 100%, it is currently showing 124%. Has anyone seen this before.
Thanks
Cache Hit Ratio
Mar 18, 2005I have a large dell server with 4 processors, and 8 gig of memory on win 2000 advanced with sql 2000 enterprise edition running a 3rd party app. My cache hit ratio averages about 76%. I thought the gneral rule was if you get below 80% to add more memory. However my memory manager shows I am only using 71% of my memory and have a full gig available. I have the sql server set to use about 7.1 gig of the 8 gig on the server. My ? is if I am only using 71% of my memory, will will adding more memory actually help my cache hit ratio
View 5 Replies View RelatedCache HIT Ratio Problem
Jul 23, 2005HelloI am tring to figure out why our SQL server is a bit sluggish fromtime to time.It is running a dual XEON, with 2.5 GB RAM, and a fast SCSI I/O subsystem setup as follows.OS, mirrored 2 drivesSQL DATA 16 HDD RAID 10SQL LOG 4 HDD RAID 10SQL tempdb 4 HDD RAID 10OS = win 2003SQL = sql2000 standard editiondbcc showcontig shows me nothing special, it looks okI launch performacne monitor and add SQL server cache manager: hitratioand it is constantly at 7% and never changes up or down, it is justconstant.Can this be correct? and if so it sounds rather bad, we have ahandfull of large tables that are heavily used and enough RAM to holdthem all in RAM so I really do not understand why the cache hit ratiois not higher.Any hints would be greatrgdsMatt
View 9 Replies View RelatedBuffer Catche Hit Ratio Counter Always Is Maximum (100). WHY ?
Sep 26, 2000Hi,
In m*y SQL server 7.0,
when using Performance, I see in graph: Buffer Catche Hit Ratio Counter
(SQLServer Buffer Manager objects)always is maximum (100). What does this mean ? What's the Buffer Catche Hit Ratio?
How do I configure SQL server to performance?
Thanks in advance.
DB Engine :: DMV To Check Buffer Hit Ratio On Several Servers
Oct 30, 2015I'm collecting performance data via DMV to check the buffer hit ratio on several servers. Sometimes I get values high above 100% hit Ratio.
Example (50050%):
SQLServer:Buffer Manager:Buffer cache hit ratio 2002
SQLServer:Buffer Manager:Buffer cache hit ratio base 4
Getting Reliable Information About Cache Hit Ratio
May 5, 2004Maybe I am just a lot better at this than I thought, but I figure that somewhere there is a mathematical rule that is being overlooked. When I run dbcc sqlperf (lrustats) on some of my production machines, I sometimes end up with a cache hit ratio (which is defined as a percentage, mind you) that is slightly over the limit:
Statistic Value
-------------------------------- ------------------------
Cache Hit Ratio 100.00898
Cache Flushes 0.0
Free Page Scan (Avg) 0.0
Free Page Scan (Max) 0.0
Min Free Buffers 331.0
Cache Size 4362.0
Free Buffers 9434.0
I suspect some counter somewhere is getting wrapped around its 4 byte limit. Is there any reliable source for getting statisics about SQL Server performance? Users tend be unreliable and say everything is slow.
T-SQL (SS2K8) :: Procedure Cache Hit Ratio
Jun 20, 2014I'm putting together some monitor scripts, have buffer cache ratio etc etc but struggling to get an accurate script for the current procedure cache hit ratio...
View 1 Replies View RelatedBuffer Cache
Sep 30, 1999Help, have recently upgraded from 6.5 to 7.0 and have come across a problem with performance. The problem appears to relate to the buffer cache being flushed, the buffer cache hit ratio drops from 98% to 0% in a matter of a second. It then very slowly grows, then is flushed again, then increase slowly upto 30%.
Does any one have any ideas as to what would flush the buffer cache?
Any comments would be much appreciated - cheers
Can't Clean Buffer Cache
May 16, 2007Hi,
My problem is that I cannot completely clean buffer cache on SQL Server 2005 version 9.00.2047.00 (probably SP1).
Right after I run DBCC DROPCLEANBUFFERS in the context of my database (this is development server, and so far I am only the one who is working with a particular database), I run a script that quetries sys.dm_os_buffer_descriptors view also from the context of my database to make sure that the buffer cache is really clean. However it shows large number of entries totalling 42 MB.
I ran both DBCC an the script in the past too, and it always showed nothing in the results, that means that buffers were really clean. The reason why I am running this is for benchmarking of existing and new application.
Does anybody have any idea, suggestions, how to troubleshoot this issue ? I already closed all connections to this database, but rebooting the server is not an option since other people are also working on it.
Thanks
Performance Monitor -- Buffer Cache Object
Jul 2, 2007Hello,
Does the performance counter Buffer cache object refer to Data cache and procedure cache or just refers to Data cache???
I was of the opinion that Buffer cache means data cache and Plan cache means procedure cache. Can someone throw some light???
Regards
Jaideep
DB Engine :: How To Use Particular Query In Buffer Cache Permanently
Aug 3, 2015I've a spatial (GIS) Data which is used frequently insertion, updation.
5 lakh records insertion in daily basis. when I trying to generate reports last 3 days or one weak, it takes 20-30 minute.
very disappointing while playing with clients. how to boostup and perform fast.
I think as so once we set query plan in buffer permanently then i would be faster than ever.
SQL Server 2008 :: Identify Size Of Data Cache Allocated From Buffer Pool
Oct 20, 2011How do i check the size of the datacache allocated from the buffer pool by sql server?
DMV or anything to show me the pool allocation sizes for the various pools in sql server i think i may be able to work from there.
SQL 2012 :: Log Buffer Waits
Sep 1, 2015Last Sunday on our Primary server I saw some blocking and the First spid that blocked everything was waiting on LogBuffer wait. At that time the server was not running hot and our DB is on SSD's. There was no memory pressure(1 TB of memory on the server) It is strange why we should get LogBuffer wait when we are running on the fastest disks possible and there was not much action going on the DB.
View 4 Replies View RelatedSQL 2012 :: Backups And Buffer Pool
Jan 23, 2015I am sure I have seen in the past in a monitoring tool that PLE drops off to 0 whenever we do a backup. I was doing some reading around this however and found something that said backups use a different portion of memory external to the buffer pool (minmax settings).
Is this correct and how can I tell how much memory will be required for a backup?
SQL 2012 :: Query Notifications For More Than Just Cache?
Jan 13, 2015All the recommendations I see from Microsoft docs is to limit the use of Query Notifications (QNs) to notifying connected clients when changes to mostly-static reference or configuration data occur, and to keep the number of overall query forms in play and connected clients to a minimum. Any way regarding a more integral use of QNs and Service Broker from a web app to notify n-web servers (farm) of an update to data that could be updated concurrently and quite frequently, or with a system where the technique is used extensively with lots of different query forms?
View 0 Replies View RelatedSQL 2012 :: Plans Not Staying In Proc Cache
Feb 25, 2015On one server I'm having an issue with and it having such a small procedure cache.
Server has 60GB of RAM assigned to its min and max server memory settings, optimise for ad hoc workloads is disabled.
Procedure cache at the moment on the server is 2.41MB with only 6 objects in side all related to mssqlsystemresource database, I can see stuff dropping in for user databases, but as soon as the proc has finished the plan is removed from the cache.
Buffer cache is in the 17GB mark, free pages around the 42GB mark so around 60GB used with a bit in stolen pages, but no proc cache.
All other servers in the environment are reporting over 8GB of proc cache in use which is more healthy.
Using Spotlight to monitor all of this.
Whats wrong with this one server and it not keeping the plans in cache.
SSDT Error - Size Necessary To Buffer XML Content Exceeded Buffer Quota
Apr 18, 2012I encountered the following error while attempting to preview an RDL report I was developing in VS2010 using SSDT:"The size necessary to buffer the XML content exceeded the buffer quota"
View 3 Replies View RelatedReporting Services :: Size Necessary To Buffer XML Content Exceeded Buffer Quota
Oct 7, 2015We have a set of reports with same header section in all the reports. So while developing a new report i used to copy that header section to the new report with same dataset names (without any change) , but while rendering the report it is throwing error " The size necessary to buffer the XML content exceeded the buffer quota".
View 2 Replies View RelatedError: The Buffer Manager Failed To Create A New Buffer Type
Apr 28, 2006Hi
I have a master package that executes a series of sub packages run from a SQL Agent job. One of those sub packages has been stable for a week, running at least once per day, but it just failed despite having been run once already today with the same set of input data.
There were a series of errors showing in the event log for the Execute Package Task starting with "Buffer Type 15 had a size of 0 bytes.", then "The buffer manager failed to create a new buffer type.", then "The Data Flow task cannot register a buffer type. The type had 32 columns and was for execution tree 3.", then "The layout failed validation." and finally "Error 0xC0012050 while loading package file "C:[Package].dtsx". Package failed validation from the ExecutePackage task. The package cannot run.".
SQLIS.com reports the constant for the error code as DTS_E_REMOTEPACKAGEVALIDATION ( http://wiki.sqlis.com/default.aspx/SQLISWiki/0xC0012050.html ).
I then ran the package on my dev machine in BIDS and it worked fine, so I re-ran the job on the server and this time that package executed ok, but another one fell over but did not put anything in the event log.
Does any one have any idea what happened?
TIA . . . Ed
SQL 2012 :: Use Of Running DBCC Free Session Cache?
Feb 12, 2015What is the use of running DBCC FREESESSIONCACHE.
How frequently can we do this on all the databases.
What happens if we schedule to run it every 1min.
Are there any advantages/disadvantages of running this on all databases.
SQL Server 2012 :: Query Tuning With Each Run Of Fresh / Blank CACHE
Jun 4, 2015I am using SQL Server 2012 Express.
I am doing performance tuning of SP/Query in Dev-Test environment.
I found that SQL Server caches plan between successive executions.
So if I test/execute SP 10 times, after 1st or 2nd execution, SQL server will pull-up plan-info from CACHE...Not from SQL SERVER Or Database...
Means i am not getting correct answer...
I found this 2 commands:
DBCC FREEPROCCACHE
DBCC DROPCLEANBUFFERS
But they say that executing above command might interfere/bother other people executing other query/sp on this server.
They also say that: Freeing the plan cache causes, for example, a stored procedure to be recompiled instead of reused from the cache. This can cause a sudden, temporary decrease in query performance.
Part of query was using Dynamic-SQL executed with EXEC command.
I replaced that with SP_EXECUTESQL.
How can I start testing of each SP-run with Fresh/Blank CACHE ?