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.

learn more… | top users | synonyms

0
votes
1answer
23 views

Soft delete to improve performance: all wrong?

A few years back I read soft delete would improve performance of deletion, because instead of actually removing the item and impact the clustered (and all other) indices, it would just change a value. ...
0
votes
0answers
9 views

In MySQL why is the first batch executed through client-side prepared statement slower?

I have around a million lines to be inserted into a MySQL (InnoDB) database, so to speed things up I turned to batch/multi-line insert. To be specific, I connect to the database (I'm using Java, so ...
1
vote
1answer
17 views

MySQL/InnoDB - Clustering Index with UUID

In MS SQL Server it is possible to cluster an index on a non-primary, non-unique key. For example, if I wanted to create a clustered index on the insert date to prevent page splits and fragmentation ...
1
vote
2answers
20 views

Awful execution plans after migrating from MySQL 5.5.11 to MariaDB 5.5.41

We just migrated our web site database from a server running MySQL 5.5.11 to one running MariaDB 5.5.41. Everything is working mostly fine, except there's at least one query from our storefront that's ...
0
votes
2answers
32 views

MySQL - best practices/ how to speed up "update, else insert' queries? Insert + delete faster?

I'm running an ETL process and streaming data into a MySQL table. Now it is being written over a web connection (fairly fast one) -- so that can be a bottleneck. Anyway, it's a basic insert/ update ...
1
vote
1answer
45 views

Database design - load multiple excels daily

My first post ever :) Apologies if I am not so clear with my question - here I go... I have a design problem from database schema perspective. My use case is following: On a daily basis, system ...
1
vote
2answers
49 views

Many columns vs few tables - performance wise

Yes, I am aware that data normalization should be my priority (as it is). I've got a table with 65 columns storing vehicle data with columns: used_vehicle, color, doors, mileage, price and so forth, ...
1
vote
0answers
16 views

How to improve performance when joining against coalesce

In an effort to remove a caching layer from our application, I'm building a number of views to encapsulate the different ways a user can have access to a piece of content - one per "rule" of access. ...
1
vote
0answers
31 views

Performance impact in orders of magnitude with Dynamic SQL [closed]

This started as a problem debugging a SSRS performance problem where I found reports were timing out when they previously weren't. Finally I traced down the SQL the report server was submitting, and ...
0
votes
0answers
82 views

Table-valued Function XML Reader [closed]

What makes the Table-valued Function XML Reader so slow? We are using SQL Server 2012 Standard to shred XML columns into tables and find it to be unacceptably slow for our business environment. The ...
1
vote
2answers
39 views

Dynamic SELECT and place result in variable columns

Edit: I use Microsoft SQL Server Management Studio, I believe it's SQL 2008R2. Sorry, new to this. I've got a complex question, at least, I think so since I can't find the answer after excessive ...
2
votes
1answer
58 views

SSRS Blocking Processes

We have a busy SSRS Reporting server (SQL Server 2008 R2) on which we see frequent blocking between the below processes: [dbo].[CheckSessionLock] [dbo].[WriteLockSession] We are aware that some ...
1
vote
1answer
14 views

mysql dump import incredibly slow on my developer's machine

I have an SQL dump, it's pretty big (411 MB) and it took 10 minutes to import on server A, the same import on my workstation B has an estimate (pipeviewer) of 8 hours to import (it imported 31 MB in ...
0
votes
0answers
26 views

Load Large data set SSIS AWS EBS

We have configuration of SQL 2012 std edition hosted in Amazon cloud that has data disk of 3 TB, Index disk of 3 TB, Log disk of 500 gb all raid 0 stripped. Am trying to load a table that has 8 ...
-1
votes
1answer
31 views

What MySQL activity eats CPU? [closed]

I have noticed weird CPU consumption peaks for MySQL process. When I monitor running queries, it's empty or some reasonable queries being executed. How do I better address the problem? Is there a ...
2
votes
1answer
81 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 ...
1
vote
1answer
31 views

How do I optimise XPath Querying over a large dataset?

I have a table that has 220 M rows. Also the table has a xml column that has XML data. I have configured single file for data and another ndf for index. Table's primary key is guid column. When am ...
3
votes
0answers
44 views

MS SQL Server IO read increase appear randomly

The number of read (IOPS) in my MS SQL Server database increased randomly even during the night (low activities) from 0.3 MB/SEC (normal) to 25-30 MB/SEC. After like 30 minutes, it's capped to 6 ...
2
votes
1answer
57 views

Can this UPDATE be faster with indexes?

update line_items set product_id = dups.latest_product_id from line_items as li join products p on li.product_id = p.id join vendors v on p.vendor_id = v.id join vendorgroups vg on ...
4
votes
1answer
109 views

Combine multiple queries into 1 query

I have a message table in Postgres 9.4 that contains a words field of array type, with random words of a message. Currently I have millions of messages: \d messages Table ...
0
votes
0answers
24 views

Are there any known benchmarks/statistics on UnQLite?

I came across UnQLite the other day in Stack Overflow and it has me intrigued for some software I'm working on. However, very few tests have been published on how well it performs. There are plenty of ...
2
votes
1answer
59 views

Counting per status group makes query very slow

I have an Intranet system developed that takes in orders and every order item has their own status, i.e. "Printed", "Labelled", "Filed", etc. This query will need to count how many items there are in ...
0
votes
1answer
35 views

Oracle: How to AUTOTRACE in my program

You can display the results of EXPLAIN PLAN with explain plan for select * from foo; select * from table(dbms_xplan.display); How can I similarly display the results for an AUTOTRACE in my program? ...
1
vote
1answer
28 views

What is a scaleable database design for querying items and only returning those a particular user has not already seen?

I'm looking at database architectures that will allow the storage of a list of items a user has already seen so that I could subsequently query the items table and only show the user items they had ...
1
vote
1answer
28 views

Storing multiple IDs in column or in new table

I'm fairly new to the databases and I'm now creating little project where I have a database and I want to store deck of cards into the table where each card has its own ID (for example 52 cards in a ...
0
votes
1answer
28 views

How to improve mysql replication performance reading the relay logs in slave?

I have a mysql 5.5 row-based replication being done. The slave is slowly getting delayed relative to the master. On show slave status I see the distance between Master_Log_File and ...
2
votes
1answer
28 views

Converting a GraphDB schema to a relational database schema

I currently am using a graph database and am considering moving off of it to a relational database like Postgresql. My concern is that I have lots of relationships between entities (since this is ...
1
vote
2answers
39 views

Speeding Inserts of longtext or longblob columns

i'm currently migrating a DB2 database to MySQL, using SQL WORKBENCH Tool It basically does a select from DB2 and Insert to DB2. It works fine, but on the tables with longblob or longtext columns ...
0
votes
0answers
31 views

Tunning MySQL Variables

we have a dedicated mysql server with 10 CPU and 32G of memory After doing some readings came up with those configs : # This was formally known as [safe_mysqld]. Both versions are currently parsed. ...
1
vote
0answers
31 views

Query for a table with paging and filtering vs. CTE (common table expression)

Intro In PostgreSQL 9.3: I am building a query that fetches data for a table that supports sorting, filtering and paging. Think Customers for example, you want to show name, surname, some detailed ...
2
votes
2answers
56 views

unusual relation, binary aspect

I have question very unusual for databases. I’m not a good English speaker, but good English reader :) so for explanation I’ll give you examples. Part1 In MySQL, I have two tables with relations ...
-1
votes
2answers
87 views

Why is “select join insert” so much faster than “loop insert”?

MySQL docs state that the time required for inserts has these approximate proportions: Connecting: (3) Sending query to server: (2) Parsing query: (2) Inserting row: (1 × size of row) ...
1
vote
0answers
25 views

Performance Implications of Explicit Collation Conversions across Linked Servers

I locally host host databases from two vendors on two different SQL instances, but on the same network. These servers frequently communicate with each other (through joins and whatnot), so we have ...
3
votes
1answer
129 views

Can SQL Server 2008 R2 extended events execute stored procedure or query?

I'm trying to use extended events to track queries that never complete using Event Pairing as a target. (see this question I asked a few days ago). The event pairing target should let me find ...
2
votes
1answer
25 views

Is using MySQL views a good translation mechanism?

We want to use a foreign vendor MySQL database, but the whole schema is barely understandable by our development team. We could alter the schema to rename tables and columns once for all, but the ...
0
votes
1answer
51 views

Performance of MySQL BLOB fields processing

Suppose, I have large (about 1 GB) strings in ASCII encoding. I have to choose whether to store them as separate blob fields or split each one of them into smaller pieces and then store them as ...
1
vote
0answers
47 views

Is it possible to trace queries that never complete with SQL Server 2008 R2?

Running SQL Server 2008 R2. We have some queries that typically take less than one second to complete, but, occasionally, they are taking longer than 30 seconds which causes a client timeout. ...
0
votes
1answer
75 views

Improve Query Performance

I have the following sqlite3-Tables: db.execute("""CREATE TABLE IF NOT EXISTS STATIONS (StationUID INTEGER PRIMARY KEY AUTOINCREMENT, StationNumber TEXT NOT NULL, ...
0
votes
1answer
33 views

InnoDB Table has backed up INSERT and UPDATE queries, high CPU

I am running an MySQL DB with all InnoDB tables. I often have many queries backed up for the same table when I run SHOW PROCESSLIST; Basically, I keep a table of every logged in customer and update ...
0
votes
1answer
60 views

Can mutli-threading java client cause high CPU utilization of SQL Server 2008?

I am a Java Developer, not a DBA, and would like to consult about an issue encountered in high CPU utilization in the SQL Server 2008 (not in the Java app server). The Java client uses ...
3
votes
1answer
200 views

Can't get Dell PE T420 (Perc H710) perform better than a MacMini with PostgreSQL

It's months that I'm trying to solve a performance issue with PostgreSQL. SYSTEM CONFIGURATION Our deployment machine is a Dell PowerEdge T420 with a Perc H710 RAID controller configured in this ...
2
votes
0answers
48 views

Case Statements, subqueries, and datediff

First time posting on this website so please let me know if you require any other information. This first section of code worked perfectly and resulted in correct information. [Field 1] = (CASE ...
2
votes
0answers
60 views

How to resolve RESOURCE_SEMAPHORE and RESOURCE_SEMAPHORE_QUERY_COMPILE wait types

We are trying to figure out root cause of slow running sql server queries hitting/fetching data from one of the database , size 300 GB, hosted on server with below configuration: Windows server ...
0
votes
0answers
20 views

DB space vs query complexity tradeoff

I have a dilemma - Right now I have a query that I do constantly - joining 5 tables on different columns, calculate stuff per row, distinct on that, and do that with offset and limit (pagination). I ...
3
votes
2answers
289 views

RAID10 vs. RAID5 for data files

We are trying to evaluate the potential performance improvements that could be gained by switching an existing applications .mdf files to a RAID10 LUN vs. the existing RAID5 LUN they are living on ...
0
votes
3answers
41 views

MySQL Date field: filter by LIKE vs MONTH()

I have a CRON task that needs to extract customers with birthday in a given month, from a MySQL INNODB table. The birthday field is indexed and of type DATE. I can query the customers table by either ...
1
vote
1answer
99 views

SQL server not using the memory allocated

We have noticed that for one of our SQL server with below configuration ,memory is not getting availed as allocated. SQL server 2005 SP4, 32 bit Windows server 2003 R2 SP2, 32 bit with 16 GB ...
0
votes
1answer
74 views

Most efficient way to set up a database handling millions of links? [closed]

I'm looking at making a site that will potentially have up to a million users, and each user will have hundreds/thousands of links connected to a set of sites, as well as other info. I'm using mysql ...
0
votes
1answer
18 views

I have a DB that is locking up from numerous updates to a table: Should I convert it from MyISAM to InnoDB?

FYI: I don't believe this is a duplicate question, I've looked and most are general questions with vague answers. See more specifics below: Currently a database I am in charge of locks up every once ...
1
vote
2answers
184 views

Is it a good idea to include a value column (e.g. from measurements) in an index?

Is it a good idea to include a value column into an index for a table which has many million rows? For example a measurement table which looks kind of like this: CREATE TABLE measurements ( id ...