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2.519 performance questions.

I have a query which takes around 17 seconds to complete. Here's the EXPLAIN (analyze, buffers): What I noticed is that maximum time (14 seconds) is taken in the "Index Scan using responses_form on ...

I am using Postgresql 9.3 on an Ubuntu 12.4 machine. I've only recently started studying database and database design, and I am to create a database that includes text that will later be searched ...

I have a very simple query " select * from ap_statistic " running in my servers. the servers have the same hardware and software configuration (CPU 8 core, mem :32G, OS: redhat 5.5, mysql version: 5....

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 ...

I have a Joomla app that takes my MySQL instance down all the time. It uses too much CPU and performs too many queries without using indexes, queries very large tables and is using non-optimized ...

I am creating friendship between user A and user B. So far my table looks like this: friendship_request | key:send_user | key:recv_user | sent | friendship_request_history | send_user | recv_user | ...

We recently moved SQL Server to SSD and the performance gain is not that great. SQLIO shows enormous gains (15-100 times faster), getting sequential read/write speed up to 6GB/s. But when we do a ...

I'm seeing a CPU spike every 5 minutes (though it's not FIXED on the 5 minutes, every so often it's 6 minutes between a spike, then 5, 5, 5 again). None of my code runs on a 5 minute interval (it ...

I have run into an odd issue where SQL Server 2016 Standard Edition 64-bit has seemed to have capped itself off at precisely half of the total memory allocated towards it (64GB of 128GB). The output ...

Having a merge publication for replicating BLOBs (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 ...

I have a table of around 30 million retail products, with various INT columns that describe sales counters and pricing at different retailers. I'm supposed to display well over 70 different rankings ...

What are the reasons that lead to terrible high Paging faults. The following is the topas information and background about the Environment. OS: AIX 6.1 Softwares: Oracle 11gR2 Paging Space:30720 ...

My query looks like SELECT * FROM table WHERE id IN(2,5,6,6,9....) The "IN" expression may include thousands of ids, which may be duplicated. Is it affects on performance, or I should clean the ids ...

I am trying to differentiate between performance when I have non clustered index on certain columns and, when it isnt there. For example: I have a table named Employee and following columns: ID (PK,...

I've received a database that was previously on SQL Server 2008R2 but was just put on a SQL Server 2014 instance. There were no maintenance tasks run of any kind run on the database since 2014 (e.g. ...

We've done what we can to index things intelligently, but we're beginning to scale up our database usage and have decided scale up (?) from Azure's S4 tier to P1. It looks like P1 has fewer DTUs and ...

One of the instances in the sharded cluster is reaching 100% CPU and it's not even the primary shard in the cluster. How can I examine the reason why only one shard is reaching 100% while the ...

I am working on a project where a customer is able to customize his/her combo meal that contains multiple customizable food items. I have created a "Meal" table joined with "Items" so that multiple ...

I'm running a 15GB database on SQL Server 12.0.5207. Server is a virtualized Windows Server 2012 R2 with 16GB RAM and 4 CPUs. Yesterday, we set ALLOW_SNAPSHOT_ISOLATION to ON, to check if it would ...

I'm trying to extend PostgreSQL to index bit strings up to 1000 bits. (These bit strings are created by quantization of high-dimensional vectors, so for each dimension up to 4 bits are assigned). ...

Monitoring software has indicated average lock wait times rising to 500ms during the night. Is there any way of confirming which locks these were as we currently do not log any performance data to a ...

I've started to use MySQL 8 (8.0.12), and I'm realizing that the "inserts" are slower in this version than MySQL 5.6 or MySQL 5.7. It doesn't matter if the table is MyISAM or InnoDB, with just one "...

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 ...

My SQL Server sometimes reports a high amount of Lazy Writes. e.g. "Lazy Writes per second is 119 Writes/sec" What should I be checking to find out why this is high? What are potential causes?

I have restored the backup of the database from SQL Server 2008 R2 to SQL Server 2016 and now facing the performance issue. How can the issue be solved without changing database Compatibility?

So I'm testing on our dev server to change MyISAM to InnoDB and am having a huge performance loss. Here is my.cnf: innodb_file_per_table=1 innodb_flush_method=O_DIRECT innodb_buffer_pool_instance=2 ...

My friend decided to learn SQL Server and T-SQL. However, he has a Mac machine. It is my understanding that SQL Server's primary use case was to be run on Windows. What potential issues may he run ...

I have a project that I am working on and I was wondering what's the best approach to map out this schema looking at it from a performance perspective. This is how my data looks like { "...

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 ...

I have created a collector set in Windows Performance Monitor which logs to a SQL table using an ODBC connection. The collector set runs everyday from 00:00 and starts polling and stops polling for ...

I came across this issue recently and couldn't find any discussion of it online. The query below DECLARE @S VARCHAR(1) = ''; WITH T AS (SELECT name + @S AS name2, * ...

I have implemented a cluster include three nodes: two stored nodes and one garbd (also haproxy - load balancer). Some information about servers: SSD 480G Raid1 Memory 32G Swap 16G 2xCPU, number of ...

I am having an issue with Aggregate Pushdown for float/real data types. According to the documentation, Aggregate Pushdown is supported for "Any datatype <= 64 bits" or 8 bytes (): ...

I got issues with some geo IP query. So basically here is create code of table: CREATE TABLE `geo_ip_city` ( `id` INT(5) UNSIGNED NOT NULL AUTO_INCREMENT, `begin` BIGINT(20) NOT NULL DEFAULT '...

Our application collect logs and writes them into PostgreSQL database. Currently each client has a separate database deployed on client's machines. But we want to make it "software as a service", ...

I'm having trouble with a big INSERT...SELECT in my DB. For context, the targeted table already have around a million entries and my SELECT query return approximately 2 millions. On a production ...

I have a table with 2.5 Millions of Postcodes. I have to populate a textbox while the user is searching for the Postcode so the query has to be very fast. The table is composed by: ID (Primary key)...

I want to check the performance of specific queries in a Postgres database on a regular basis. Also, I want to be able to check the change in performance of different queries with any change in my ...

I have a production SQL server and a linked server (Azure SQL Database) I join two tables to do update Table A - small table A in TempDB that has only 100 rows on SQL Server Table B - on linked ...

This question is about SQL Server index performance with a varchar(2000) as an INCLUDE in a covering index. I’m trying to improve performance in an slow and unstable database application. In some ...

Is there a upper bound for an array column? I am getting this error when inserting into the array field - PG::Error: ERROR: index row size 3480 exceeds maximum 2712 for index "ix_data" Here's my ...

We have a MySQL instance for unit tests. Our unit tests work very heavily on MySQL. Therefore, we put /var/lib/mysql dir in tmpfs file system because we don't need persistent data in unit tests. Our ...

Let me acknowledge, I don't know much about database efficiency neither Service Broker as a whole, where I work the dba that used tp handle these kind of things left some weeks ago. The company uses ...

Let's say I have a MySQL JSON data type called custom_properties for a media table: An example of the json data stored in the custom_properties column could be: { "company_id": 1, "uploaded_by": "...

I have a system to teach English. For each word someone learns, I record: LearnedWords -- Id -- UserId -- WordId And for each new text that I give to a learner, I want to indicate what ...

Edit 3 (additional explanation and improved table aliases) A computer system is used to control the sales of multiple products across multiple online stores. Each store has a selection of shipment ...

I have two tables with ~1M rows indexed by their Id's. the fallowing query... SELECT t.* FROM transactions t INNER JOIN integration it ON it.id_trans = t.id_trans WHERE t.id_trans = '5440073' OR it....

In the database are ~700k images. Each image has its own tag(s). I want to be able to search images by the tags with a full text search query. The query does exactly what I want but it's very slow. ...

I'm getting no answers from my host, but I suspect their DB servers are compromised. I was getting some ridiculous page loads for requests to a standard Wordpress installation - upwards of 30 seconds,...

Our primary authentication database that is used for 100k+ users, and growing is a VM on a shared machine that we want to extract into its own isolated hardware. This will let us isolate resources, ...

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