Categories
Database Development

Will Postgres use a multi-column index when setting multiple colums not null?

Typically, when I set a column not null, if it doesn’t have an index then I add it first, so that postgres can (hopefully) use the index while doing the table scan while locking the table, so that the table is locked for a shorter amount of time. I want to set several columns not […]

Categories
Database Development

Availability Group: Is it possible not to do automatic failover for particular groups?

We’ve got two Windows Server 2016 with SQLServer 2016 on AWS EC2 instances (node 1 and node 2) Because we’re using a standard edition, we’re limited to having one database per availability group. Therefore, we ended up having 20+ availability groups (we call it “slave” groups) to contain all of our databases and one availability […]

Categories
Artificial Intelligence (AI) Mastering Development

Using a model-based method to build an accurate day trading environment model

There are several different angles we can classify Reinforcement Learning methods from. We can distinguished three main aspects : Value-based and policy-based On-policy and off-policy Model-free and model-based Historically, due to their sample-efficiency, the model-based methods have been used in robotics field and other industrial controls. That is happened due to the cost of the […]

Categories
Database Development

SQL Deadlock History

What query can I run to display historical deadlocks? I can see the current days deadlocks by going into “Management – Extended Events – system_health – package0.event_file” and looking at the xml_deadlock_report entries

Categories
Database Development

Performance of Query where time captured from SP statement completed differs by large from RPC completed

I am unable to understand the performance of below query when collected data from XE events: Query DECLARE @Importdate DATETIME = ISNULL (( SELECT ImportDatetime FROM Customertable where CustomerID = 1 and OrderID =1 ) , ’01/01/2000′) This part of statement returns just 1 row SP statement completed shows 40 secs RPC Completed for above […]

Categories
Artificial Intelligence (AI) Mastering Development

Can you find another reason for sample inefficiency of model-free on-policy Deep Reinforcement Learning?

The following mindmap gives an overview of multiple reasons for sample inefficiency. The list is definitely not complete. Can you see another reason not mentioned so far? Some related links: interactive mindmap Reddit post asking the same question related SE question with only a few reasons all mentioned here

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Database Development

UnUnstall Sql Server 2016

I have Sql server 2012 and Sql server 2016 standard named instance on same server and we would like to update Sql 2016 to Sql 2014, Is it any way we directly upgrade the version on a same server where two instance instead of uninstalling process as sometimes uninstall cause issue? Thank you for help!

Categories
Artificial Intelligence (AI) Mastering Development

Can you find another reason for sample inefficiency of model-free on-policy Deep Reinforcement Learning?

The following mindmap gives an overview of multiple reasons for sample inefficiency. The list is definitely not complete. Can you see another reason not mentioned so far? Some related links: interactive mindmap Reddit post asking the same question related SE question with only a few reasons all mentioned here

Categories
Database Development

Difference between “Require SSL” and “Require X590” SSL option on MariaDB

I am learning enabling two way TLS set on MariaDB. For this it requires an user account with X590 SSL option. I read theory but still not clear about the difference. also, when should use which option. Please help with this query.

Categories
Database Development

MySQL 8.0 table with JSON column that uses JSON “merge” operations has 500k rows but analyze table shows 7MM

I have a database table that according to TABLE STATUS has 7MM rows, but when I SELECT COUNT(*) it only has 500k rows. This is a problem because table growth is increasing and we’re running low on storage now. here is schema: MySQL 8.0.15 CREATE TABLE `tasks` ( `task_id` binary(24) NOT NULL, `task` json NOT […]