An evaluation of whether a system works well enough to be fit for purpose. Normally performance refers to the speed with which a system completes an operation or set of operations over time.

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18 views

3 tables joins performance issue

DB: Postgres 9.4 schema: table a: id, score table ab: a_id, b_id, b_type table b: id, name, type I am trying to get top 10 result in the following format: name, count(group by name), ...
2
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1answer
32 views

Slow inserts in oracle 12c inmemory table

We are running some tests to check the in-memory performance on a 12c (12.1.0.2.4 EE) RAC. Servers have 56GB memory and 20core CPUs. Our plan is to have a few read-performance critical tables in ...
0
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0answers
10 views

High disk IO from MySQL database on Ubuntu

We have a MySQL database (the master in a master-slave setup) running on Ubuntu that is experiencing high disk IO as reported in newrelic and by iostat. Now, the server normally has ~150 connections ...
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0answers
18 views

Seconds behind the master is getting increased how to reduced that. since i haveupdated my salve and started back the replication [on hold]

MariaDB [(none)]> show slave status \G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: ...
2
votes
1answer
99 views

What is the best storing device for DB transaction log?

I'm using MySQL with InnoDB storing engine. Transactional log is placed to dedicated HDD. Still as it is HDD atopsar shows big load (>50%) to this HDD because of big amount of small IOs (about 50 ...
2
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1answer
156 views

What are possible causes for consistently volatile INSERT performance in MySQL tables?

I have a Java program running on a VM that is sequentially feeding a queue of single row INSERTs through a single connection to a MySQL server on the same VM. The queue execution is not artificially ...
4
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2answers
3k views

“freeing items” taking forever on inserts, updates and deletes

Recently I migrated all my MySQL database tables from MyISAM engine to InnoDB. I'm using the DotCloud MySQL service as my server (http://docs.dotcloud.com/services/mysql/). After the migration, ...
9
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2answers
280 views

Minimizing Indexed Reads with Complex Criteria

I'm optimizing a Firebird 2.5 database of work tickets. They're stored in a table declared as such: CREATE TABLE TICKETS ( TICKET_ID id PRIMARY KEY, JOB_ID id, ACTION_ID id, STATUS str256 ...
0
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1answer
1k views

How to configure my.cnf for Mysql 5.1, which is using too much CPU?

I am new Database engineer. I am having trouble in my server which is using too much CPU on database query(simple count statement). I have googled about it, so i found out it depends on system ...
0
votes
1answer
166 views

my.ini configuration for a huge server

I have developed a web based app in PHP MySQL and Flash Builder. It was running fine until a few days ago when the client began to connect a lot of users. Then the app started to freeze and sent ...
0
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0answers
25 views

Identifying high load sql

We had an oracle outage some days ago. We have inbetween awr tools. I genarated awrrpt report but dont see anything suspicious. Which report should I generate to see sql, which caused very high cpu ...
0
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1answer
23 views

Is it good to save Keywords stored by users in a new DB schema?

My question is more from the schema design and of further performance of the DB. I'm designing a DB schema which will store primarily strings. Actually, users work on these string, as normal mortals, ...
3
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1answer
85 views

ASP.NET & SQL Server 2012 timeouts once a month

We have an intranet site which works fine, except one day a month. There are slow queries, unoptimized tables, tables with ~8 million records, etc. but daily usage is fine, although some ...
0
votes
1answer
20 views

MongoDB 3.0 Indexes maximum limitation

I have a mongo DB that store user's public messages. Each message should be categorized by at least one TAG (3 max in an array) The TAG can be anything up to 32 characters. ([0..9a..z]) the Tag ...
2
votes
1answer
54 views

Deleting large amounts of cascading records with minimal locking

I'm looking for a strategy to purge large amounts of logically deleted data from a MySQL database. The deleted records are in a relatively small table, but are referred to with many ON DELETE CASACDE ...
1
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1answer
72 views

Is adding the join columns to a table a good practice to improve performance?

Say we have 3 tables, A, B and C. Assume all table relationships I refer to below are 1 to many. Suppose A joins B in a1 = b1 and B joins C in b2 = c1. Is it a good practice to add b2 and a1 to ...
2
votes
1answer
364 views

Database design for a table with both bulk insert and single row insert

I have to design a table where records will be inserted in two ways. Bulk insert from a batch process from a delimited text file between 2 - 3 million rows in a short burst. Later the same records ...
5
votes
4answers
6k views

Slow query on large table with GROUP BY and ORDER BY

I have a table with 7.2 million tuples which looks like this: table public.methods column | type | attributes ...
0
votes
1answer
31 views

Fastest way to do bulk import in MYSQL

I have got a question about the fastest way to copy a large number of records (around 10 million) from 1 table to another in MySQL. The target table has 1 primary key, 4 indexes and 3 foreign key ...
0
votes
1answer
50 views

Mysql Slow when join query running increaed

Our Mysql dedicated server box always have around 40 - 80 active user connection , so the query speed very good and Cpu usage low . (around 4 - 8 core from 24 core) but sometimes when some wordpress ...
4
votes
3answers
145 views

Setting maxdop 1 vs setting the threshold for parallelism high

I am looking at a possible fringe case for parallelism settings. I've long since followed the credence that maxdop 1 is a viable option for Microsoft Dynamics CRM databases. As the nature of the ...
0
votes
1answer
214 views

Select Query takes more than a minute to retrieve data

I have a table that has 99 columns, all of them are not needed but they were there when we started. There is a Primary Key (Objectuid) which is a GUI and has the Clustered Index on the PK. The Table ...
2
votes
2answers
2k views

Improve MySQL Query Performance - Too many records

I am using MySQL RDMS for a contact management system. Now a days my database grew in size and contains more than 1 million records. Checking duplicate phone numbers became a big issue during ...
5
votes
1answer
260 views

What units is Page Life Expectancy in?

I'm currently using the following query to get the Page Life Expectancy from SQL Server: declare @PLE int select @PLE=cntr_value from psql1.master.sys.dm_os_performance_counters where ...
5
votes
1answer
52 views

How can I minimize impact of expensive queries in Database A on Databases B, C, D

How can I configure SQL Server so that activity in 'Database A" has minimal impact on users in 'Database B' The Context Our (very large) production SQL Servers have a lot of databases on them ...
7
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1answer
106 views

Instant File Initialization on Shared drive

I asked something similar to this before, but previously I had asked about moving backups to a shared location. This time I am curious: if I want to restore a database on a shared drive, do I need to ...
7
votes
0answers
60 views

Two servers, different execution plans. Several orders of magnitude difference in run time

Two servers, Development and Live. Live server is an Amazon RDS SQL Server Web instance. Both servers have identical schema and data. There is a good spatial index on the geometry column. On my ...
7
votes
1answer
92 views

Low CPU Utilization but High Signal Waits

I have a server with 16 CPUs that is configured with a max degree of parallelism of 8 and a max worker threads setting of zero. For a given hour, my signal waits were 20% yet my OS CPU utilization ...
5
votes
2answers
2k views

Linked Server Risks

I'm implementing a new feature which requires data from databases on multiple servers. I just need to union data from all these servers and sort it. The two options that come to mind are: Use linked ...
2
votes
2answers
186 views

where is the index physically located in MySQL database

Just wondering where is the index info physically located in MySQL database if I have indexed a table with ALTER TABLE contacts ADD KEY (columnName); ? it will stay with that table and add a new ...
1
vote
1answer
213 views

MongoDB Insert Performance

I have some data which are aggregated in chunks and later pushed into another collection. The problem is that aggregated data pushing to another collection is very slow and takes from few hours and i ...
2
votes
1answer
762 views

SQL Server performance is slow when migrated from SQL Server 2012 to SQL Server 2014

We are trying to migrate from SQL Server 2012 to SQL Server 2014 on Windows 2012 R2 OS. After the upgrade, we are doing performance testing and observed huge difference in running a simple query from ...
3
votes
1answer
66 views

4m Rows in MySQL, ~5 Minutes to Run Query

I have 2 tables, a users table and a log table which literally logs each time a user signs in. What I'm trying to do is grab a list of all users with a certain rank who have not logged in for over a ...
1
vote
1answer
32 views

Why is my Target Server Memory slightly higher than my Total Server Memory?

I'm doing a performance test on a high traffic (16000+ users, estimated 1000+ concurrent at peak) Microsoft Dynamics database. The server has gone on line a few months ago, and I'm doing some tests to ...
1
vote
3answers
329 views

Oracle Compatible Parameter to set

Is there any difference in setting the Compatible Parameter to 11.2.0.0 vs 11.2.0.4 ? Are there any advantages / dis-advantages ?
9
votes
5answers
11k views

Why using innodb_file_per_table?

There are many articles exaggerating (IMHO of course) the need for innodb_file_per_table. I understand that with innodb_file_per_table, there should be a better control over the individual tables; ...
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 ...
0
votes
1answer
217 views

MYSQL: How to improve performance of inserting over 1M rows to a table with over 100M indexed rows

I have this mysql table: CREATE TABLE `codes` ( `code` bigint(11) unsigned NOT NULL, `allocation` int(11) NOT NULL DEFAULT '0', `used` tinyint(1) NOT NULL DEFAULT '0', PRIMARY KEY (`code`), ...
5
votes
1answer
168 views

How big of an impact does NUMA really have?

I was reading up on Non-Uniform Memory Access (NUMA) and I was wondering how much of a difference it can really make? Another way to word that, what level of throughput is required before this ...
15
votes
1answer
2k views

SQL Server - Anyone use SUMA, trace flag 8048, or trace flag 8015?

Recently included SQL Server startup Trace Flag 8048 to resolve a serious spinlock contention issue in a SQL Server 2008 R2 system. Interested to hear from others who have found usage cases where ...
1
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0answers
27 views

Speed of Split Database vs ODBC with SQL Server vs ODBC with Azure Cloud

I would like to be able to host my data either in the cloud or in SQL Server, as having all my data in one Access file just doesn't seem the most secure to me (or am I wrong?). My forms contain many ...
1
vote
1answer
533 views

Internal query on CDEF$ and CON$ very CPU bound

I am checking an application (Infor ERP LN) that loads a lot of data into an oracle 10.2 database. While checking one of the user sessions with SQL_TRACE and its output with tkprof, I found that the ...
0
votes
1answer
36 views

Creating index for large table is taking forever

I am trying to create Index for a large table with row count of 496,000,000 and the database is on SQL Server 2012 Enterprise edition. I know how to create index but its taking forever and would like ...
3
votes
0answers
66 views

Creating MSSQL Performance Baseline Monitoring

In order to get an overview and compareable data my current task is to create a performance baseline to get some figures about the different productive sql instances. My thoughts are: I want to ...
0
votes
0answers
41 views

Upsert - Should I verify the row exists first, attempt an update, or try to insert first?

In a software that I'm working, I have a table with a few columns and a id. In some events in my software, I need to update some column of a record with a certain unique field (other column), but ...
1
vote
1answer
29 views

Things to keep in mind while editing Mysql “my.cnf” file

Today I tried to boost mysql's(installed in my system Ubuntu 14.04) performance as I have many sites(PHP/Magento) installed in my system which relies on mysql as database server, but when I edited the ...
2
votes
1answer
178 views

MS SQL high tempdb disk I/O during merge replication of BLOBs

Having a merge publication for replicating BLOBs (sql type - image), got very high tempdb disk I/O for my size of data. Publication is download-only and has no filters. High disk I/O is caused by ...
0
votes
1answer
142 views

Large long-running reporting queries are causing very slow new mysql connections

Usually, mysql's connecton time is in the 0.001 second range. However, when I run a large reporting query (that spans multiple tables with aggregates), I get tons of warnings saying that new mysql ...
0
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2answers
46 views

Identical SQL Server databases hosted in the same physical DB server

We have hosted similar SQL Server 2014 databases TestDB and TESTDB_Copy on the same physical server. The two databases are almost the same and there may be minor differences in the number of records ...
3
votes
1answer
174 views

PostgreSQL performance worse when adding CPUs

I ran into a strange behaviour when benchmarking PostgreSQL. The setup is like this: Virtual box VM, with 3 GB of RAM. The host has 16GB of RAM and 4 CPUs. Ubuntu 14.04, standard PostgreSQL 9.3 ...