All Questions

I've just set up a publication, and I'm attempting to get the snapshot to apply faster. So far the Distribution Agent is respecting the MaxBCPThreads settings, but the Snapshot Agent is not. I'm ...

This question is a continuation of optimizer behavior exploration in regards to VALUES construct started here and here. I want to ask about VALUES and APPLY this time. Using CROSS APPLY to alias an ...

My MySQL instance is getting killed by the Linux oom_killer due to huge consumption of memory by mysql when inserting into longblob columns. This occurs when restoring a mysqldump which contains a ...

1. We have a schema definition in Google's Protocol Buffers format that we use to generate code for different gRPC implementations (Python, PHP) 2. We have a database (PostreSQL) that is initialized ...

I have a PostgreSQL 9.1 database that contains 10M+ rows and some text fields that need similarity and %word%-like searches, so I decided to use trigram indexes. Initially, I started to use GIN ...

Why would an availability group's number of worker threads in an HADR pool increase well beyond minimum usage of "typically, there are 3–10 shared threads" per replica? In one case we've observed ...

I am working on an existing MySQL database. My task is to create a new data model for a billing system on that existing application. I have created a conceptual data model (click to enlarge): ##...

I am trying to debug a deadlock scenario which has been puzzling me for quite some time now. I am wondering if someone can shed any light into how this can happen. Here is the deadlock output: ------...

As I mentioned in this question I'm trying to understand the working of clock hands. Simply put clock hands move when there is memory pressure so that cache entries can be removed or the cost can be ...

Description: RocksDB is a key-value storage so we can simply serialise the list of objects & store the value corresponding to a key. This would be ok if the data in the list is small enough. ...

I'm trying to find a good alternative to SQL Developer for performing queries and scripts on Oracle instances. I find DBeaver to be an interesting tool, it has a lot of great features, BUT it seems ...

I have a follow-up question to a question I have previously asked on SO. Instead of the query from my initial question, I want to convert the following into relational algebra: List the names and ...

Sometime last week my CTRL+TAB behavior changed. I used to hit CTRL+TAB, release, then I would be in my previous document tab. Now I hit CTRL+TAB, release, and the nav window is still open requiring ...

We recently converted a table to memory optimized data. Our backups have all ballooned (3x300GB files to 3x600GB files for Full, 3x50GB to 3x250GB for Diffs), and startup has been getting ...

I'm doing the conceptual model for a Decision tree database. The goal is store any Decision tree. I have four entity types: DecisionTree, Node, Branch and Leaf. Each Decision tree is composed of ...

Trying to diagnose an problem, I've ran into that inconsistency. In SQL Server Profiler, the RPC Starting event uses the regional settings to write real numbers (example: in Portuguese(Brazil) 14.5 ...

In pgAdmin 3, the dialog to perform a backup allowed you to check and un-check the tables you wanted to be part of your backup. In pgAdmin 4, either I am unable to find this feature, or it is not ...

I am attempting to query between 0 and 65,000 rows from a table. The server is using Microsoft SQL Server 2014, and I have no way to change the hardware on the server. Schema [Id] (PK) INT ...

I have a PostgreSQL table with a key (bigint) and a value (double). The table has tens of billions of rows. I have a single btree on the (key,value) for aid lookups by key. The table is never updated. ...

My ordering application uses Oracle 11g Database. This DB has a primary table ORDERS and multiple child tables like ORDER_DETAILS, PLAN etc. ORDERS table is LIST partitioned on STATUS column and all ...

I've been writing a backup script for sharded replica-sets and it's almost done. Except I can't seem to get it to successfully start the balancer backup after everything's all said and done. Here's ...

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....

In How It Works: SQL Server 2012 Database Engine Task Scheduling, Bob Dorr explains some of the changes for worker scheduler assignment in SQL Server 2012. He mentions that some of the improvements ...

The cast from double precision (float8) to numeric rounds to 15 significant decimal digits, thereby losing information. Clearly, more precision is possible. The cast to bigint (for values within its ...

The table: CREATE TABLE [dbo].[Session] ( [SessionId] UNIQUEIDENTIFIER NOT NULL, [CID] INT NULL, [DEST] VARCHAR (50) NOT NULL, [...

I have an issue with an SSIS package, that when deployed via VS2017 to the integration services catalog is not actually being deployed. This is an individual package deployment, and not a project ...

TL;DR: Inserting a large number of rows with no collisions is MUCH faster than (not) re-inserting the same rows, BOTH using the INSERT IGNORE syntax. Why is this? I would assume that the index lookup ...

We're trying to see whether a client is able to reach a database server, as it's receiving error: [DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied. The error ...

I recently started running into the Sort exceeded memory limit of... exception on an aggregation pipeline in MongoDB. I got around this by setting AllowDiskUse=True for the aggregation. However, I ...

In some circumstances, I've been told not to do a VACUUM FULL (or CLUSTER) of a table that is in production, because that will exclusively lock it for longer than wished. The same might apply to ...

I have two SQL Server user accounts on a database that behave differently on INSERT / UPDATE / DELETE. SQL Server version is 2008 R2 (10.50.4042, 64 bits). UserA can do these commands (on any table). ...

Is it possible to generate a UUID version 4 (completely random) in MySQL? I would like to use it as a primary key. Use Case Many systems will insert to the table, some may specify a UUID when ...

Using PostgreSQL 9.5. It seems like Postgres is being inconsistent with how it compares strings similar to لى. A unique constraint is considering some strings equal that GROUP BY is considering ...

I have a table with the following fields: p1 p2 s1 s2 where p1 -> player1, p2 -> player2, s1 -> game1, s2 -> game2 The number of players can vary from 3 - 10. The table have the results between them....

TL;DR: Does a table referred to via schema.table get held in table cache? I have a large number of client databases that our application connects to based on an http request. These are used for every ...

I'm looking into providing DB level change tracking within my system. I need to be able to track changes at an entity level, rather than just individual tables. Right now, we have triggers on each of ...

So my production db in RDS apparently either crashed or was rebooted during a version update, and upon being restarted mysql couldn't load one of the innodb tables: as evidenced by the following error ...

Oracle 11g R2 Unfortunately our application has per row security "features". We have a query that looks about like this: Bad, slow: SELECT someRow, someOtherRow FROM bigTableA a WHERE EXISTS ( ...

I've had a SQL Server 2019 server working great for the past few months, but it started stopping by itself since last Friday. This morning, I installed latest cumulative update on it. Here is my ...

I have a list of commands I need to execute, all of which are contained within a table I've named myQueue. This table is a little unique in that some commands should be grouped together such that ...

I am testing MySQL JSON_ARRAY and JSON_ARRAYAGG functions in order to move some application expensive processes to SQL stored functions. In the following e-commerce application example, I am trying ...

I'm mostly posting this for community awareness, but feel free to give feedback if you think there is a solution other than coding around the problem as we are doing. Crossposting this from my bug ...

We accidentally deleted the directory rm -rf /data/db which was our MongoDB path, and thanks to extundelete, we recovered it and got the directory /data/db. Here are our files in the directory, and ...

I can't figure out why our AWS postgres server has consumed all of it's space. We just had to up the storage space allocated to it, but can't find any hint from postgres that it's using that much ...

Lately, I've been trying to clean up a group of projects that my company received from an outside contractor. Among them is an SSAS cube, with an associated data warehouse. The contractors generated ...

I have been fooling around with Postgres 10 logical replication, trying to learn about it and potentially apply it to a couple of projects. I have observed something that I am wondering about, but I ...

We run a db.m4.10xlarge instance on Amazon's RDS. It runs 3 fairly busy databases and has a replica instance connected to it. Over the last few weeks I noticed the swap usage has been steadily rising ...

I am trying to understand the impact of deletions to bloat of tables and indexes after large number of inserts and deletes. The inserts and deletes are following a rather strict pattern: first the ...

I know how to use SQLpackage.exe. I can export from SQL Azure and create a bacpac. I can also Import to SQL Server via SQLPackage.exe. I want to export or import without the users in the database. The ...

We are using a change tracking solution to export increments for BI purposes for years now. But it was running directly on the production database. To lower the load on the system we wanted it to run ...