Questions tagged [multi-thread]
The multi-thread tag has no usage guidance.
25
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SqlServer User and IP address auditing using Triggers + SESSION_CONTEXT – is this thread safe?
Problem
We use a combination of triggers and values set in SESSION_CONTEXT to implement dta change auditing on our SqlServer database.
Unfortunately, we have started to notice that the username and Ip ...
0
votes
1
answer
366
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MySQL's atomic and thread safe nature
I understood that MySQL is thread-safe, which means that even though two threads trying to access the DB, it will be safe since there is a lock mechanism.
But I like to ask one question, which you ...
- 121
1
vote
1
answer
2k
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Race conditions. When 2 thread try to update in same entity in table [duplicate]
We all know that race condition is something we should avoid. We should not try to access the same variable or memory when using multiple threads.
But I have some tricky cases. Let's say we have a ...
- 121
0
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1
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304
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Will an underpowered mirror host cause: The query processor could not start the necessary thread resources for parallel query execution [duplicate]
We recently moved our 2016 sql server mirror into Azure, but it's on an underpowered machine. Our main database server has 16 physical cores with hyper threading and 2 numa nodes. We have set the ...
- 101
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1
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490
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Why does insert on duplicate-key error create a share lock?
In the mysql docs is the following example for locking on insert:
INSERT sets an exclusive lock on the inserted row. [...] If a duplicate-key error occurs, a shared lock on the duplicate index ...
- 137
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1
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239
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How many operations SQL Server support per connection
I am making a multi threaded application in which I will use a single SQL Server connection and perform select, insert, update and delete.
So once my application starts, it will open connection ...
- 441
2
votes
2
answers
5k
views
How to calculate the max number of worker threads in SQL Server?
I use 64-bit OS with two CPUs (each of them makes 7 logical processors) and with total number of logical processors equal to 14.
When I run this code I get 2048
SELECT max_workers_count FROM sys....
- 1,233
1
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1
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1k
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MySQL: Performance issues in heavy multi-threaded environment
I have 23 of these tables in one database:
CREATE TABLE foo1 (
DateTime datetime NOT NULL,
BidOpen decimal(11, 5) NOT NULL,
BidHigh decimal(11, 5) NOT NULL,
BidLow decimal(11, 5) NOT NULL,
...
- 639
1
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0
answers
151
views
GTID ignore error on parallel replication
Im getting an error in replication where GTID and parallel replications are enabled. Now I want to skip one transaction.
I didn't find a way to do that.
Last_SQL_Error:
Worker 48 failed executing ...
- 1,860
2
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0
answers
579
views
How get process that is locking Database on SQLite?
I'm developing a iOS app using SQLite. I've got a class to manage SQL's operations, basically read, write and update. In many cases I get a SQLITE_BUSY error, so I want know which process is using the ...
- 121
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4k
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How can I disable database lock in sqlite with python?
I made a application in python and it should read and write simultaneously in multiple instances(multi CMD widows)(multi-threading). each thread is configured independently so it will not change the ...
0
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1
answer
648
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Deadlock error in inserting bulk of records to MySQL database using trigger and Qt multi threading
I have a multi thread program (In this case in Qt) which every thread at a specific time, inserts 500 records in a MySQL table (I call that as A_tbl) and also there is a trigger for A_tbl that inserts ...
2
votes
1
answer
4k
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UNION Queries run in Parallel form or not
I have three tables and I want to select data from these three tables in parallel form to increase the performance.
I'm running a query like this.
SELECT * FROM table1
UNION ALL
SELECT * FROM table2
...
- 73
5
votes
2
answers
3k
views
Identity Column in Concurrency, Multithreading, Parallel Processing
Our company would like to understand the effects:
If we have single table with Primary Key Identity column, int primary key IDENTITY(1,1),
and the Application is conducting multi-threading parallel ...
user129291
3
votes
1
answer
9k
views
SQL Server Threads and Degree Of Parallelism
My understanding about SQL Server threads is that SQL Server breaks down an execution request within a session into several tasks and associates each task with a worker thread. So SQL Server always ...
user99201
2
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6
answers
12k
views
Run queries in parallel
I am running a sql script on mysql 5.7.18 ubuntu server 16.04 that does a large number of updates in one table. Each one of the 50k updates takes under a second but the total run time is very long (>...
- 201
3
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1
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732
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MySQL, many writes waiting on disk i/o access
I'm seeing a disk i/o problem with a MySQL DB under the following scenario:
24 CPU's total on the computer
22 threads writing simultaneously to separate tables
each write is done using INSERT INTO ......
- 31
4
votes
3
answers
296
views
Identify threads with maximum difference in time
I have many parallel executing queries in my SQL Server database. I need to find out queries where the difference in time for the longest thread and the shortest thread is high (excluding co-...
- 899
2
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0
answers
1k
views
MySQL queries waiting for other queries to finish
We have 30-40 different projects in Python and PHP that update, insert and select more than 1 million rows of data in MySQL DB every day.
Currently we use InnoDB Engine for our tables.
The problem:
...
- 21
9
votes
4
answers
4k
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How to get response from stored procedure before it finishes?
I need to return partial result (as simple select) from a Stored procedure before it is finished.
Is it possible to do that?
If yes, how to do that?
If not, any workaround?
EDIT: I have several ...
- 1,163
0
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2
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3k
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Updating rows in tables concurrently using Multithreading in Java
I have an excel file with 50000 rows and I'm updating a MySQL table using hibernate by uploading that excel file from a Java Program. It is taking a huge time to update all the rows. Can it be ...
- 1
2
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1
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532
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What does Oracle use for handling a client connection (process or thread)?
SQL Server 2016 and MySQL 5.7 use thread-based connection handling.
PostgreSQL 9.5 uses one operating system process for each individual connection.
According to Oracle 12c documentation it's not ...
- 897
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1k
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Multi-threaded inserts vs serial
I have a large database application on SQL Server 2012 Standard Edition which receives data from hardware in chunks of 500-1000 (100 byte) rows every few seconds through a stored procedure. Would a ...
- 113
1
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1
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2k
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Multi-thread Informatica connections to use different processors on target database server
See this question for reference.
Can data streams from Informatica to SQL Server be multi-threaded?
I've got most of my problem figured out. I've split up the one large table into four smaller ...
- 2,072
2
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0
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164
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Can data streams from Informatica to SQL Server be multi-threaded?
Suppose we have a database server, with SQL Server on it. And we are moving data from another database server, through our Informatica server, and onto that SQL Server database server. And our SQL ...
- 2,072