Improving the performance characteristics of a database application or system.

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18
votes
2answers
11k views

Configuring PostgreSQL for read performance

Our system write a lots of data (kind of Big Data system). The write performance is good enough for our needs but the read performance is really too slow. The primary key (constraint) structure is ...
4
votes
3answers
484 views

Speed up creation of Postgres partial index

I am trying to create partial indexes for a large (1.2TB), static table in Postgres 9.4. My data is completely static, so I am able to insert all data, then create all indexes. In this 1.2TB table, ...
2
votes
2answers
7k views

Hyperthreading & MySQL InnoDB Thread Concurrency Performance

I have a dedicated DB Server with the following specs" Ubuntu 12.04 LTS Server Intel(R) Xeon(R) CPU X5670 @ 2.93GHz 12 Cores MySQL 5.5.29 64 GB RAM RAID10 We are currently doing Hyperthreading ...
1
vote
1answer
201 views

MySQL performance tuning

I would like to optimize my MySQL DB. I noticed some important points as follows: Enabling Query cache. Using memory storage. (I know pluses and minuses of this. Being I am having static tables, I ...
2
votes
1answer
6k views

Why isn't oracle using an index for distinct query ?

This is the scenario SQL> exec dbms_stats.gather_table_stats(user,'TM', cascade=>true) PL/SQL procedure successfully completed. SQL> SELECT SEGMENT_NAME , SEGMENT_TYPE , BYTES / 1024 / ...
1
vote
1answer
47 views

How can I 'further' improve my table and queries

This question is an extension of this question. Where Rick James kindly provided a list of things I should change in my table and query. I also changed my application so that unused filters weren't ...
0
votes
0answers
45 views

Reducing the time when retrieving all records from large databases

I have to retrieve most of the records from large table, I'm talking about approximately 3 millions rows. I'm even using this site as a guide for tuning the database. It is not enough, it takes an ...
7
votes
2answers
4k views

Latin1_General_BIN performance impact when changing the database default collation

I have set the database collation to Latin1_General_BIN, to make string comparisons case-sensitive. Will this have an impact on performance? Will it have any impact on DML or DDL operations in the ...
4
votes
5answers
2k views

How can I prove that the following T-SQL is bad for performance?

I have recently inherited a codebase with a large amount of Stored Procedures. The system they are supporting is encountering numerous performance problems which I am looking in to. A number of the ...
1
vote
2answers
93 views

Select the minimum of a calculated distance value without sorting

I have a query dealing with geo distances. The query is super fast, returning in roughly .1175 seconds on my 2.24 million row table. However, I only need the lowest distance, and using the built-in ...
2
votes
1answer
266 views

Stack Dumping and performance degradation of sql server process [closed]

I would like to say that today i got first time SQL Server log message in My SQL Server 2012 Database. ***Stack Dump being sent to D:\MSSQL11.MSSQLSERVER\MSSQL\LOG\SQLDump0012.txt * *****************...
1
vote
2answers
1k views

Optimize MySQL query_cache_min_res_unit

My query cache settings are the following: mysql> SHOW GLOBAL STATUS LIKE 'Q%'; +-------------------------+----------+ | Variable_name | Value | +-------------------------+----------+ ...
7
votes
3answers
2k views

Dealing with CXPACKET waits - setting cost threshold for parallelism

As a follow-up to my previous question on perf troubleshooting a Sharepoint site, I was wondering if I could do something about the CXPACKET waits. I know the knee-jerk solution is to turn off all ...
5
votes
2answers
143 views

reporting space consumption to files in filegroup - how to reverse-engineer the algorithm spreading data across files

I would like to know how to calculate the distribution of data consumed per file in a filegroup, back to the index (HEAP, CLUSTERED, NONCLUSTERED) storing it. My intention is to define which I/O goes ...
3
votes
1answer
270 views

In-memory SQL Server log file

I have a SQL Server instance that is used solely for the purpose of reporting and also for preparing data to be loaded into Analysis Services. Its data comes from another SQL Server instance which is ...
2
votes
2answers
63 views

Can moving tables to another MySQL database help performance?

I want to know if I using different databases can help performance. I have one big table support_chat with more than 5 million rows. I need to scan this all the time (3s with ajax) to check new ...
1
vote
2answers
912 views

Very high load avg for MySQL database [closed]

I have a backend server which response to my clients app, it has more than 20k~25k hit per second and this make my server load average very high, I believe that my MySQL config is not appropriate. In ...
1
vote
1answer
48 views

Do threads in cache still use memory?

I was studying about how and how much memory allocated to each connection thread and found below MySQL tutorial: http://dev.mysql.com/doc/refman/5.1/en/memory-use.html There is a point mentioned as ...
0
votes
1answer
66 views

Hashed and heap indexed object storage table insert and query performance

This question is partly to ask advice and assure this design is sane. I state the the desired properties upfront here, then go in more detail in the rationale and follow up with the design and example ...