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.

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7
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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 ...
4
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1answer
2k 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 ...
4
votes
2answers
2k 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 ...
11
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3answers
4k 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 ...
5
votes
2answers
1k views

ORA-04031: unable to allocate bytes of shared memory (“”,“”,“”,“”)

I am receiving this error in a development database. It happens on some specific queries (simple inserts and deletes via .NET application). The database is used by one user, and error happens ...
7
votes
3answers
4k 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 ...
6
votes
2answers
6k 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 ...
3
votes
4answers
1k 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 ...
4
votes
2answers
7k 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, ...
6
votes
4answers
5k 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
3k 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 ...
7
votes
4answers
13k 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) ...
8
votes
2answers
10k 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
3answers
3k 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 ...
8
votes
3answers
5k 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 ...
2
votes
3answers
326 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 ...
1
vote
3answers
131 views

in-memory SQL database system [closed]

In an application, I am using mysql's TEMPORARY TABLE. Since this application does not need permanent tables, I wonder if I can find an alternative RDMS designed for memory tables. I hope to find an ...
29
votes
4answers
3k 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 ...
13
votes
3answers
7k 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 ...
7
votes
4answers
3k views

MySQL Cluster RAM requirement

From MySQL 5.1, the data doesn't need to be entirely in memory anymore. I've read that the indexed columns (I think the entire index structure) must still be in memory (MySQL High Availability, 2010, ...
3
votes
3answers
9k views

How to use insert delay with the InnoDB engine and use less connection for insert statements?

I'm working on an application which involves a lot of database writes, approximately ~70% inserts and 30% reads. This ratio would also include updates which I consider to be one read and one write. ...
6
votes
1answer
418 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
1answer
6k views

How do you increase MySQL performance using current server resources?

I have a MySQL database and some of my queries became slow. Query time is not stable. Most of the queries are fast, but some of them (may be that reads and returns less data) take long time. I know ...
1
vote
2answers
835 views

Why would increase in innodb_buffer_pool_size slow down MySQL?

5.1.68-cll - MySQL Community Server on CentOS The system has 32GB of RAM. I increased innodb_buffer_pool_size from 10240M to 15360M (10GB -> 15GB). Time taken for a series of identical operations ...
0
votes
1answer
232 views

How can lots of ram (128 GB) be used to improve MySQL 5.5 index creation?

This is similar to another post of mine, but now I have a different table structure, and it's still unclear what MySQL parameters should be changed to take advantage of the extra ram my machine ...
6
votes
2answers
16k 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 ...
5
votes
1answer
1k views

SQL Server - How to determine ideal memory for instance?

We have some virtual machines that have X memory allocated to them. This amount of memory is somewhat random. It was allocated to the machine because that was the amount of memory the physical ...
5
votes
2answers
335 views

Can I prove my database does not have memory issues?

(This is a continuation of do indexes consume memory) A fellow database developer believes we are having memory issues. He has seen increased run times in some standard queries - going from under 10 ...
1
vote
1answer
777 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 ...
0
votes
1answer
318 views

MySQL Memory Grows Over Time

I've got a server running a LAMP stack with 1GB RAM that is maxed out on RAM usage. What I'm observing is that directly after a reboot, it drops to 25% usage, and then slowly climbs over time so that ...
20
votes
3answers
9k 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
1answer
1k views

SQL Server Maximum and Minimum memory configuration

What are the correct settings for min-memory and max-memory in this use case? The server has 8GB ram, dual Intel Xeon processors, running Windows Server 2008 R2 / Sql Server 2008 Standard Edition. ...
1
vote
4answers
156 views

Large table with historical data allocates too much of SQL Server 2008 Std. memory - performance loss for other databases

Based on this question and the answers given: SQL 2008 Server - performance loss possibly connected with a very large table I have discovered memory allocation problem with SQL Server 2008. ...
1
vote
1answer
41 views

Adding new tables — memory usage increases

I added more tables to my mysql server. 20% increase in tables that are all innodb. I have 200 + databases that use the same schema. Does adding more tables increase memory usage? I am using about ...
1
vote
3answers
2k views

How long will a temporary MEMORY table persist if I don't drop it (MySQL)

I'm using a recursive stored procedure in MySQL to generate a temporary table called id_list, but I must use the results of that procedure in a follow up select query, so I can't DROP the temporary ...
-5
votes
1answer
140 views

Recommendation for mysql please :MySQLTuner [closed]

>> MySQLTuner 1.3.0 - Major Hayden <major@mhtx.net> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options ...