performance's questions - Chinese 1answer

2.463 performance questions.

I'm using mysql 5.7 I'm making app that has 2 activities: list of entities and viewing single entity (full). The full entity has 7 related entities and 100 columns. On the list activity I need only ...

We recently observed a serious performance degradation in a SQL Azure database running in Standard3 performance tier - CPU utilization went from ten percent to fifty percent to almost one hundred ...

I'm trying to get to the bottom of what I'm thinking is a performance issue when creating in memory temporary tables. The underlying query I have looks to me to be pretty well optimized. The explain ...

I have an application running on Amazon MySQL/RDS that needs to maintain 2 weeks of transactional history after which time data can (usually) be purged. Because this isn't a hard rule I cannot use ...

Let's say I have a Text field called "description" inside "products" table. Inside this field I will store 3 values. I will separate them with two pipes ( || ): requirements: - bla bla.. (a text) || ...

Is there a way to measure the (avg) time it takes mssql to process a transaction across a set of transactions (or spanning a certain period)? I'm thinking potentially of sys.dm_os_performance_counters)...

I know and understand that there are performance hits in storing blob data in the database, but the blob portion of the data is going to be rarely retrieved/viewed, it is for smaller data (the vast ...

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. ...

The title pretty much sums up the question itself: Is there a rule of thumb regarding the values for tmp_table_size and max_heap_table_size MySQL properties? I've had a serious performance ...

I have quite an annoying problem. I want to use INNODB as my main database engine and give up on MyISAM as I need the former for using galera-cluster for redundancy. I copied (description follows) ...

I have a table with 128'914'635 number of rows. Some columns cardinality (i.e. address, lastname, firstname) is equal to the total number of rows in the table (128'914'635). The queries are really ...

As I've been getting more into web development, I've started trying to identify how some of my favorite websites work behind the hood. However, the logistics of one website have me stumped. I used ...

I can see a decrease in performance after underlaying virtual configuration has changed from 1 NUMA node with 10 CPU cores to 2 NUMA nodes both with 5 CPU cores. Users complain that things are ...

I have 2 tables: Create table Files ( FileId BigInt unsigned not NULL auto_increment, FileName varchar(255) not NULL, PRIMARY KEY (FileID), UNIQUE KEY FileName (FileName) ); Create table ...

I'm trying to improve the performance of a georeferencing feature in our application. For every address in our system, we need to store which of several boundary types it is located within (local ...

I am having a strange issue with a slow query under certain conditions: I have made a few tests and was able to isolate the issue to one single table called products_description (all the tables are ...

I have a query on a table tab and this table has a column a: select * from tab where a = :a; but the index is not hitting. Please let me know what could be possible reason (It was asked during an ...

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'd like to store some geometric positions in my MySQL database. For this I use the POINT datatype. Almost everywhere I read that the function GeomFromText should be used to insert data in the table. ...

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 ...

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 created some comparing benchmarks for several databases. Two of them are VoltDB and Redis, two In-Memory-Databases. I tested some inserts and found out, that on both systems my inserts take slightly ...

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 ...

Is that safe to run such query without escaping input? Assume noone can guess the random string I generate. SELECT * FROM foo WHERE bar = $long random tag$ THIS NOT ESCAPED $long random tag$ What ...

I am trying to find out the Query which is consuming high CPU, but can't do it so. This command top -H gives me the high CPU consuming thread PID, but i cannot match them with my processlist output. ...

GI have a question about performance of SQL over MPLS. I have a client with 3 localizations. We want to centralize the server environment and migrate all of SQL databases to headquarter. Our client ...

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,...

I have two, almost identical, databases and I am trying to figure out what is causing queries to perform that much slower in one of them. While investigating using the information_schema.statistics ...

I have a query that executes very often on our system and there is no option to change the query text. Are there any suggestions on what could be done? Any help would be appreciated. The query: ...

I have the following SQL query explain analyze select CERTIFICATE_ID, SERIAL_NUMBER, SUBJECT_DISTINGUISHED_NAME, NOT_BEFORE, NOT_AFTER, FIRST_SEEN, REVOKED, LINT_ERRORS from (...

We have a problem with one of our databases. At random times something causes our transaction log to swell up to 20x its original size (it basically fills up the whole HD, so 20x is not accurate since ...

To improve the performance created Index on one of the column in pasted query and this query is taking more time (5 hours),Earlier without index creation it was taking(1.5 hours) and after adding the ...

TL;DR: Inserting or updating table, with putting 1024 bytes into bytea column works quite slow. I have a PostgreSql 9.5.12 installation on my Desktop Linux Mint 18, with SSD drive, Core-i5, and 16GB ...

Yes, you read correctly, 59%. Some of these are undoubtedly programmer error where they are comparing an INTEGER with a VARCHAR value, but of the ones I've surveyed (out of the 5139 execution plans ...

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 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 ...

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 ...

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 ?

I'm working on performance analysis of reports, resulting from different test cases. I'm using MS SQL Server 2016 Dev edition Regarding one of the performance counters ('Checkpoint Pages/sec'), I ...

I have searched a long time and still haven't found the answer to my problem. Our Dynamics AX is generating queries with the query hint OPTION (FAST x), which sometimes forces a bad execution plan to ...

I have a PostgreSQL table. select * is very slow whereas select id is nice and quick. I think it may be that the size of the row is very large and it's taking a while to transport, or it may be some ...

Say I have a table with prices and different percents, and I need to calculate the sum of the percentage. And I run this query, SELECT i.user_id, i.payment_type, SUM(id.price), ...

I have a table in SQL Server 2016 for which I am receiving data from an API. The data was in XML format so I have to break it into columns and bulk saving it into SQL. There are 32 columns in the ...

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....

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'm having troubles to import one of the SQl dumps of Wikipedia into a local database. I've downloaded the categorylinks.sql from https://dumps.wikimedia.org/enwiki/latest/ which is around 17GB when ...

I have a query which has the following WHERE clause (note that this is a simplification. In the actual case the second parameter would be passed from code. But the following explanation applies to ...

Let's say I've the following table: id | name | created_by | updated_by | deleted_by -------------------------------------------------- 1 | alice | NULL | NULL | NULL 2 | ben ...

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 ...

Background Info Let's say I have a table in MySQL that has +1 billion records. I have a column with that contains some description of a post. We don't index, search, or sort this column in any way. ...

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