When used in the context of databases, memory refers to RAM directly addressable by the CPU as opposed to going through the I/O subsystem.
11
votes
3answers
2k views
SQL Server 2008 R2 “Ghost Memory”?
We have a dedicated SQL Server 2008 R2 machine that is experiencing some strange memory issues.. The machine itself has plenty of resources including two quad-core processors, 16gb of RAM and 64bit ...
7
votes
3answers
739 views
I am using the MEMORY storage engine but MySQL still writes to my disk…Why?
I am using the MEMORY Engine for all tables associated with a particular MYSQL query because speed of access is paramount to my project.
For some reason, I have noticed that a large amount of disk ...
5
votes
3answers
1k views
What is the default order of records for a SELECT statement in MySQL?
Suppose you have the following table and data:
create table t(k int, v int,index k(k)) engine=memory;
insert into t values(10, 1), (10, 2), (10, 3);
When issuing select * from t where k = 10 with ...
2
votes
1answer
969 views
Mysql Memory table getting many locks
On my site I log every pageview (date, ip, referrer, page, etc) in a simple mysql table.
This table has the following activity:
1 SELECT per minute
1 DELETE per minute
no UPDATE queries
Lots of ...
5
votes
4answers
7k views
Why does MySQL say I'm out of memory?
I was trying to execute a fairly large INSERT...SELECT in MySQL with JDBC, and I got the following exception:
Exception in thread "main" java.sql.SQLException: Out of memory (Needed 1073741824 bytes)
...
5
votes
2answers
746 views
SQL Server gets slow over time until we have to restart it
We have a database with a mixed OLAP/OLTP workload. The queries are quite ad-hoc and are dynamically created in the mid-tier application server. When we start the server, the performance is quite ...
7
votes
3answers
2k views
How to free SQL Server memory?
I have a SQL Server sandbox installation on my local computer. I have set the memory SQL Server instance can use to 1000 mb. When running an intensive operation, memory usage rises up to 1000 mb. When ...
5
votes
3answers
3k views
MySQL gives “Out of Memory” error when inserting a large file. From where is this filesize limitation arising?
I'm using a MySQL database to store files.
The table I'm using is structured as follows:
+--------------+----------+------+-----+---------+-------+
| Field | Type | Null | Key | Default ...
4
votes
2answers
4k views
Why is MySQL is creating so many temporary tables on disk?
Can any configuration mistake lead to creating too many temp tables by mysql..mysql tuner shows
Current max_heap_table_size = 200 M
Current tmp_table_size = 200 M
Of 17158 temp tables, 30% were ...
4
votes
2answers
2k views
Microsoft SQL Server 2008 Memory
I am running MSSQL 2008 Enterprise and in the configuration of the server the Max memory amount is set to 2147483647 MB.
My Question is, the server has 192 GB of ram,the number in the config can't be ...
3
votes
2answers
562 views
Is it bad to create many mysql temporary tables simultaneously?
I need to make heavy statistical analysis to deliver some data to users. Currently, I catch the data from mysql and process them via PHP arrays. However, mysql temporary tables are quite better ...
3
votes
4answers
752 views
Is it feasible to have MySQL in-memory storage engine utilize 512 GB of RAM?
I am considering scaling up instead of scaling out. Therefore, I am interested to hear whether it is feasible to utilize the MySQL in-memory storage engine for a database that is 500+ GB, given that ...
1
vote
3answers
208 views
RAM Impact on Oracle database operations
We are seeing drastic change in the amount of time taken for db operations depending on ram size.
The same content when inserted into a db running on a 4gb ram machine takes about 600% more than into ...
25
votes
3answers
2k views
On a dedicated database server, how much memory to reserve for the OS?
Assuming you have a dedicated server explicitly for database functions -- how much memory should you reserve for the operating system?
I realize this will probably vary somewhat depending on the ...
7
votes
2answers
2k views
What are reasons *not* to use the MEMORY storage engine in MySQL?
I recently discovered that MySQL has a "memory" engine that I wasn't aware of (most of my database work is for hobby projects so I learn what I need as I go). It seems like this option should give me ...
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 ...
3
votes
2answers
6k views
How do I shrink the innodb file ibdata1 without dumping all databases?
InnoDB stores all tables in one big file ibdata1.
After dropping a big table, the file is keeping its size no matter how big the table was.
How can I shrink that file without having to dump and ...
3
votes
2answers
4k views
Is InnoDB Engine up to speed against Memory Engine?
I am exploring the efficiency of different database engines in MySQL version 5.5.18 to see which is best suited for use with a range query on a dataset of 5 million rows:
SELECT P.col1, P.col2, ...
1
vote
1answer
88 views
Can putting mysql DB into memory or having the innodb_buffer_pool_size match the size of DB increase performance?
We have a mysql database that has roughly 80 gigabytes (GB) of data using inno_db engine. We are looking to increase performance on the database (we looked at the slow log and gone through and ...
19
votes
3answers
4k views
Is the SQL Server Express memory and CPU limit per instance?
If I have 8GB of RAM in a server and I run 4 instances of SQL Server Express, will the total memory limit used by SQL Server be 1GB or 4GB?
Would it be advisable to run multiple instances like this ...
4
votes
3answers
2k views
How much memory will a MEMORY table take up?
Let's say I have a MyISAM table with a data length of 4.8GB and an index length of 6.2GB. So, a total data size of eleven gig. How much memory would this require, were I to convert it to a MEMORY ...
