New answers tagged

0 votes

Does PostgreSQL Explain Analyze Execution Time consider Fetching time

Let's first understand what is Planning and Execution time: Planning time When you run a query there is a lot of ways server can run this query. Query planner think and decide based on statistic of ...
2 votes

Optimize the number of connections of the connection pool and MySQL

I don't use any "formulas" for tuning databases. They're all wrong, because they don't take into account the specific needs of your database and your application requests. The size of your ...
0 votes

Partitioned Tables and Indexes - what are the downsides?

I know this is an old post, but even today (in 2022), I find that SQL Server is very particular about data types. If you partition by a DateTime2(0) your where clause must have a DateTime2(0) on both ...
5 votes

Performance problems in SQL Server. Parameter Sniffing or not in my scenario?

How many records are in #e538? The engine turns that into a series of OR clauses, which I've found to be sub-optimal after a few dozen. Depending on other factors, if one of your queries has ...
0 votes

How do you tune MySQL for a heavy InnoDB workload?

Here shows a good configration for Mysql. Besides, it's better to set some system limits, like vim /etc/security/limits.conf * soft fsize unlimited * hard fsize unlimited * soft nproc 1048576 * hard ...
1 vote

Running sp_updatestats probably overrides manually done UPDATE STATISTICS WITH FULLSCAN and ruins performance

It sounds like you have heavily skewed data, which is causing the statistics histogram to not represent the full picture of the data. To ensure that sp_updatestats does a full scan on those tables ...
  • 8,316
-1 votes

Disk block size for mongodb deployment

MongoDB doesn't but WiredTiger does. See: https://source.wiredtiger.com/3.1.0/tune_page_size_and_comp.html
  • 1
4 votes

AUTOMATIC_TUNING SQL Server

Automatic Tuning is one of the Intelligent Query Processing features and depends on the Query Store. As the name suggests, it's automatic, so you can't affect it. If you already have a Query Store ...
  • 2,625
0 votes

Why would INSERT, REPLACE or UPDATE statements sometimes take over 1 second to execute?

In most situations, REPLACE can and should be replaced by INSERT ... ON DUPLICATE KEY UPDATE. REPLACE is a combo of a DELETE and an INSERT. If an auto_increment id is being used, it always burns a ...
  • 71.5k
2 votes
Accepted

What are the performance implications of using checksums vs change tracking for SQL Server

Is the difference in performance between using checksum calculations and change tracking worth pursuing? Yea, most likely in your use case. This is because of the frequency of which you're checking ...
  • 28.3k
3 votes
Accepted

Running sp_updatestats probably overrides manually done UPDATE STATISTICS WITH FULLSCAN and ruins performance

As I understand it, your issue is that you do UPDATE STATISTICS WITH FULLSCAN and then sp_updatestats (or possibly the auto update stats) kicked in and destroyed your "perfect" statistics ...
2 votes

Running sp_updatestats probably overrides manually done UPDATE STATISTICS WITH FULLSCAN and ruins performance

Yes, this can definitely cause performance issues. Especially queries that rely heavily on sorting and are executed often but on wildly varying datasets become the victim of extreme performance ...
  • 162
0 votes

Use One Table or Many One-To-One Tables

Question: What are you going to do most often with a post? Answer: Load it and display it. For that, you will need most, if not all, of those fields, including the colours, even if only once. As ...
  • 7,193
1 vote
Accepted

Use One Table or Many One-To-One Tables

It depends, and generally won't matter much one way or the other as far as performance is concerned. The reason why it won't improve performance much to split up the table into multiple tables, is ...
  • 28.3k
1 vote
Accepted

More efficient calculations of stock splits

As I mentioned in the comments, the fields that the 4 instances of your window functions are using, are the same key fields you're joining on between appl.eod_data (E) and appl.splits_view (s), which ...
  • 28.3k
-2 votes

Azure postgresql really slow compared to VM

PostgreSQL Single Server in Azure is being deprecated. You should be using PostgreSQL Flexible Server which has much improved performance and will be the long term PG service going forward in Azure.
  • 1
0 votes

Accelerated Database Recovery SQL Server

This is more of a comment than an answer but I'd start by trying to understand what might be causing the cleanup of the persistent version store and possibly try running the PVS cleanup manually. ...
  • 59

Top 50 recent answers are included