The cache tag has no wiki summary.
13
votes
4answers
550 views
Why would I NOT use the SQL Server option “optimize for ad hoc workloads”?
I've been reading some great articles regarding SQL Server plan caching by Kimberly Tripp such as this one:
http://www.sqlskills.com/blogs/kimberly/plan-cache-and-optimizing-for-adhoc-workloads/
Why ...
10
votes
2answers
1k views
Parameter Sniffing vs VARIABLES vs Recompile vs OPTIMIZE FOR UNKNOWN
So we had a long running proc causing problems this morning (30 sec + run time). We decided to check to see if parameter sniffing was to blame. So, we rewrote the proc and set the incoming ...
10
votes
5answers
3k views
PostgreSQL: Force data into memory
Is there a systematic way to force PostgreSQL to load a specific table into memory, or at least read it from disk so that it will be cached by the system?
8
votes
3answers
2k views
How to boost performance of virgin queries in MS SQL Server?
I have ASP.NET web site that does it's own independent caching of data and data does not change for long periods of time, so it does not need to query SQL Server second time with same query. I need to ...
7
votes
2answers
346 views
PostgreSQL Index Caching
I'm having difficulty finding 'lay' explanations of how indexes are cached in PostgreSQL, so I'd like a reality check on any or all of these assumptions:
PostgreSQL indexes, like rows, live on disk ...
7
votes
2answers
788 views
Is the overhead of frequent query cache invalidation ever worth it?
I'm currently working on a MySQL database where we are seeing a large number of invalidations from the query cache, primarily because of the high number of INSERT, DELETE and UPDATE statements that ...
7
votes
1answer
377 views
Definitive list of steps for SQL Server baseline testing?
Before running a performance test / baseline for an app that uses SQL Server, I want to be able to set the instance to a "clean" state, without restarting the instance. There are steps I tend to ...
5
votes
1answer
226 views
How much memory is a table taking up?
Is there a way to find out how much memory a table is taking up in SQL Server (2005 and greater)?
For example, suppose I have a table with 30 million records. I'd like to know how many pages ...
5
votes
2answers
201 views
mysql performance / cache configuration enigma [closed]
I have two mysql 5.1 instances (say A, B) hosting the same database schema. If I run (with mysql workbench) the same query on both instances I don't understand why I get very different response times ...
4
votes
2answers
133 views
MySQL: Is it safe to have a table with multiple millions of rows?
I have a very complex search query to write that will touch many tables, have conditions and joins. For efficiency reasons, I am strongly considering creating a "cache table" where I would maybe once ...
4
votes
1answer
127 views
Can I partially invalidate the MySQL table cache?
I want to set a fairly large table to MyISAM mode to keep it cached proactively. The table file is approximately 3GB.
After several hours, MySQL invalidates the entire table from cache, while < ...
4
votes
1answer
576 views
How to calculate cache misses for PostgreSQL
I'm administering a server where a tool using a PostgreSQL runs. The tool takes care of most PostgreSQL configurations by itself, but I'm observing some performance problems. I could confirm at OS ...
3
votes
5answers
2k views
Why is MySQL caching data on our dynamic PHP site?
We are having an annoyance with our PHP/MySQL site in that it seems to cache data from the database and our PHP pages are showing out of date records. In fact, there are pages that link to URLs that ...
3
votes
1answer
143 views
Reindexing and its effects on SQL cache
Currently looking into reindexing our sql database, and cannot find any information on whether or not the procedure cache would be effected. Any help or information would be great. We are using SQL ...
3
votes
2answers
219 views
MySQL cache is not getting hit by subqueries
I noticed something weird on MySQL query_cache behavior and I would like to know if this is a normal behavior.
Let's say I have an item table
ID | Item
-----------
1 | Item_1
2 | Item_2
3 | ...
3
votes
1answer
78 views
Buffer usage for index with no reads
Using SQL Server 2008 R2, the main transactional table in a vendor database is massive compared to all others and has about 14 indexes. Some of these indexes don't get used in our environment, but we ...
2
votes
2answers
215 views
Stored procedure compilation blocking due to many parameters to sp_executesql
I am seeing blocking due to locks on compiling a particular stored procedure (as described in KB 263889). Basically, several processes are waiting with LCK_M_X on the same resource "TAB: ...
2
votes
1answer
537 views
query_cache_type = 0 vs query_cache_type = 1
Recently, I moved from standard MySQL to Percona, and used the Percona Wizard to generate my.cnf.
However, I can see that, by default, the generated settings for my.cnf use query_cache_type = 0. ...
2
votes
2answers
1k views
Does Oracle cache queries when using a database link
Some vendor told us that we should not use database link between our database and theirs as the queries executed over a database link would not be cached, nor optimized.
I can't find any information ...
2
votes
1answer
47 views
SQL Server Cache population on server / service startup
We have upgraded our SQL Server instance with buckets of RAM, so it can now much more effectively cache . The issue is that it takes time (days) to populate the cache. As far as I understand this is ...
2
votes
0answers
45 views
Multithreading caching in SQL CLR
Is there any mechanism available to a SQLCLR assembly for caching that will still work when the assembly is registered as "safe"?
The cache needs to be thread-safe, so it can be shared by multiple ...
2
votes
0answers
35 views
Postgres caching and bytea
I have a DB which, among other things, stores images (as bytea, if that's interesting). It also stores users' metadata, activity logs, etc., but images currently take 500MB out of the total 600MB ...
1
vote
1answer
112 views
Where do caching servers conceptually fit in my architecture?
Given the simple well-known architecture below:
Where (conceptually) does the caching server(s) sit?
1
vote
3answers
173 views
getting error while starting memecached service with ndb engine
i am installed memcached library by following the steps in the internet.
now there is a binary file created in bin folder of mysql
now i exicuting the command memcached i am getting error like this ...
1
vote
2answers
137 views
Functioning of Oracle's Server result Cache
I am reading the Oracle concepts doc and have a doubt [about general cache mechanism ] :
PL/SQL function code can include a request to cache its results. Upon invocation of
this function, the ...
1
vote
1answer
66 views
Does MySQL's MyISAM use cache before insert?
I want to test two different Disks, one of them is HDD and another is SSD
I use exactly same information and app for both servers. They are exactly same, just one of them is SSD and another is HARD.
...
1
vote
1answer
70 views
how to use mysql temporal cache tables
I took this example from a book where visitors_today is the cache table from visitor_stored. The idea is to store all the visitors per day (visitors_stored) using a cache table.
Create table ...
1
vote
1answer
57 views
Different plans or buffers for different connections?
We had an issue in our dev environment where a procedure call timed out from the web server after 30 seconds. I traced the query and ran it manually (same params and all) from SSMS and it executed in ...
1
vote
1answer
199 views
MySQL: To use MYISAM or INNODB engine? (plot twist enclosed)
We use INNODB for all of our tables, but I have one special table, a 100+ GB reference table (only read-queries against it).
We are loading changes to this table in a nightly batch job using LOAD ...
1
vote
2answers
169 views
Cache all mysql table
Maybe it sound's like i'm an idiot... But i'm developing app with huge db on RoR. Also i see that if i do some query and after that do it one more it is doing much faster, becouse it has been ...
1
vote
1answer
175 views
Mysql: Tell InnoDB to keep a specific table or database out of pool/cache?
I have some tables that are used primarily to keep historical data, or that are only used once a day.
I do not want any operations on these tables to disrupt the more important tables present in ...
1
vote
1answer
209 views
MySQL: How do I limit or prevent caching for specific tables?
I'm currently working on a database schema for tables to hold user information on a website with integrated forums.
Right now my idea is to have all the data in two separate tables: one table with ...
1
vote
1answer
215 views
What are the pros and cons of using CLIENT_RESULT_CACHE_SIZE and RESULT_CACHE_MODE
I have multiple questions
For Oracle Database 11g Release 11.2.0.1.0
what are the benefits of using CLIENT_RESULT_CACHE_SIZE and RESULT_CACHE_MODE.
How will the CLIENT side cache be kept sync if ...
1
vote
0answers
64 views
Command line switch to disable Coherence?
We have a Java app that happens to have the coherence jar in the path.
My application doesn't need it, so I'd like to pass some type of -D variable to the JVM to tell it to ignore coherence, or ...
0
votes
1answer
48 views
Does SQL Server cache data results for DAO?
I was surprised to be confronted with the idea that using .NET and DAO one could make use of the SQL Server data cache in a way not at all possible with stored procedures (which benefit from the plan ...
0
votes
1answer
30 views
Oracle scheduler chain priority in data warehouse applications
The scenario is as follows:
We have a data warehouse type application that relies on the Oracle job scheduler and a Chain. This chain is responsible for generating materialized views (caches) that ...
0
votes
1answer
44 views
If MySQL isn't caching, then what is?
I ran a few commands to see whether MySQL is caching queries/result sets. It looks like this is not the case.
mysql> show variables like 'query_cache_size';
--------------
show variables like ...
0
votes
1answer
211 views
Qcache_free_memory not full yet I get alot of Qcache_lowmem_prunes
I just started dabbling with query cache for our CMS.
Can anyone tell me why (or at least a good guess) I get alot of Qcache_lowmem_prunes when more than half of Qcache_free_memory is free?
...
0
votes
0answers
4 views
What is wrong with table_cache hit rate?
In my.cnf I have:
table_cache = 524288
open_files_limit = 65535
Both are at max allowed value for mysql config. Both are less than max open file limit:
# cat ...
0
votes
1answer
24 views
Why is LRU is not suitable for joining 2 relations in DBMS
In DBMS, can someone please explain how the LRU (least recently used) buffer replacement policy acts when joining 2 relations in a database?
I have read that LRU is not efficient when joining two ...
0
votes
0answers
19 views
Should store procedures be cached?
Should store procedures be cached in MySQL? If so, How long it is stay in cache?
In my case, When I call one stored procedure first time, it is giving me results in 1 second, after that it gives me ...
0
votes
0answers
25 views
Req: Typical location of mysql query cache
My MVC framework (CodeIgniter) wants to know where my database (mysql 5.5) writes its query cache. My Ubuntu installation is unexceptional. Would that be /var/lib/mysql/ or further down the chain, ...
0
votes
0answers
42 views
Temporarly disable cache in oracle 11g
I want to disable the caching for my session in oracle 11g to see how long a query takes.
Is this possible or is there a better way for meassuring the time a query takes to run?
0
votes
0answers
304 views
The Oracle's Log Buffer, Redo Log Buffer Cache and Redo Log files [closed]
I need to know the difference between :
(i) Log Buffer (ii) Redo Log Buffer Cache and (iii) Redo Log files.
0
votes
1answer
93 views
getting error while installing memcached_function
now i am working with memcached with mysql cluster 7.2
for that i am installed
libevent-1.4.14b-stable.tar.gz
memcached-1.4.5.tar.gz
libmemcached-0.8.tar.gz
then
...
