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26
votes
3answers
10k 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 ...
3
votes
2answers
6k 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. ...
0
votes
1answer
119 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 ...
1
vote
1answer
709 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
3k 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 ...
0
votes
1answer
51 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 ...
6
votes
2answers
346 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 ...
1
vote
1answer
1k 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 ...
9
votes
2answers
2k 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 ...
4
votes
1answer
210 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 < ...
13
votes
2answers
4k 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 ...
2
votes
1answer
980 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 ...
2
votes
2answers
326 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: ...
1
vote
1answer
183 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 ...
1
vote
1answer
125 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?
8
votes
3answers
5k 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 ...
1
vote
1answer
90 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 ...
2
votes
1answer
70 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 ...
3
votes
2answers
704 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 | ...
1
vote
3answers
258 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 ...
10
votes
1answer
705 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 ...
0
votes
1answer
139 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 ...
6
votes
1answer
630 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 ...
6
votes
2answers
1k 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 ...
4
votes
2answers
196 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 ...
1
vote
1answer
70 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 ...
3
votes
2answers
3k 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 ...
1
vote
1answer
449 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
2answers
170 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 ...
3
votes
5answers
4k 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 ...
14
votes
5answers
10k 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?