In the database structured query language (SQL), the DELETE statement removes one or more records from a table.

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Single statement or batched delete?

I need to delete 6.3 million records from 25 tables in production. I have the following two queries, but I don't know which one will be best: delete jc from Jtable jc join J1Table j on j.JobId = ...
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Can I do anything about a very long running KILL command?

I've got a table with 103M+ records in it and takes up 70GB on the disk. I decided to DELETE (in one statement) 70% of the records. As expected, this took an awfully long time to run. I decided to ...
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2answers
2k views

Oracle: deleting data from tables leads to data file fragmentation?

When randomly deleting ~5GB from a ~10GB Oracle table, I suspect that disk space is left in fragments. Is there a way to know about the disk state and any query to defragment or shrink the space?
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2answers
246 views

SQL Server 2008 R2 - Unable to delete Login

I've been using this site for a while and this is the first time I've had to ask a question, but just wanted to say "Thank You" to everyone who has helped me in the past (without knowing they did so). ...
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Bulk Delete for Large Table in MySQL

I have a Notification table contains about 100 million rows host in Amazon RDS with 1000 IOPS, and I want to delete those rows older than one month. If I do DELETE FROM NOTIFICATION WHERE CreatedAt ...
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681 views

Copy database and clear down data (including linked tables) older than N days

I have a sizable production database (140GB) on MS SQL Server 2012, which I'm trying to automatically download to our development environments on a periodical basis (every week or on demand). I'm not ...
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1answer
256 views

MySQL trigger after insert with insert and delete instructions does not work properly

I have the following trigger created in phpMyAdmin: Table: tb_agenda Time: AFTER Event: INSERT BEGIN INSERT INTO tb_realizacao (dt_agenda, titulo, ...
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122 views

How to index for timestamp queries

I have a products table where I insert around 150,000 records a day. Most of them are redundant, but I need to keep them because of the new expiration date. I get product feeds from about 5 vendors a ...
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225 views

Could 'Maximum Server Memory' be too low for large batched delete with captured output?

I'm trying to improve the performance of a SQL server database backup program that will create a new database to hold one years worth of report records, delete report records out of the main database, ...
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464 views

Postgres 9.3 - deletes terribly slow for 10 minutes after dropping indexes/constraints

If I run a script which drops indexes (17 of them, CONCURRENTLY makes no difference except that without it I get the occasional deadlock), then constraints (20 constraints on 18 tables) and then run a ...
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2answers
115 views

Deleting rows from a table with a very small amount of expansion space

I have multiple tables that I have backed up the data in, and now am deleting the old data for the time, archiving is not an option due to space constraints at this time. I have tried running the ...
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1k views

Running parallel delete statements

Problem: I have a massive table - occupies a whopping 9.5 TBs. I need to delete around 5 mil rows from it. The best method I have come up with deletes 1 million records in 2 hours! Since I can not run ...
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77 views

Delete all highscores from a certain country

I have two tables: tbl_players tbl_highscores I need to delete all highscores that are registered from a certain country. My problem is that the language are set per player, rather than by ...
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2answers
546 views

How do I Delete A Database And Log Files With SQL 2008 Script?

While working on making an automated Delete and Restore script for my backups I ran into a snag. I can not delete the database; however, the delete button works exactly how I need it to. Can anyone ...
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2answers
642 views

Inserting data to a table which is being cleaned up by SQL job at the same time

Our app uses a table in a database and we have a Sql job set up to run overnight which executes a stored procedure which just deletes data older that from the table. DELETE FROM MyTable ...
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1k views

Delete rows in a table that has multiple FKs

I need to delete all the rows in the ContentData table that have the word 'DV95' in the htmldata column. Here is what I am using: BEGIN TRANSACTION DELETE Contentdata FROM Contentlinks INNER JOIN ...
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455 views

Mysql foreign key cascade delete

Does mysql have a way to delete all sub links if a row was deleted from a "parent" table? Example table setup is below, the issue I am trying to avoid is having to maintain a script that deletes the ...
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1answer
5k views

MySQL Query: Delete from 'table2' where column = 'value' IF column in 'table1' = 'value'

I am trying to execute a MySQL query to delete rows from 'table2' where column = 'value' IF column in 'table1' = 'value' I have 2 tables... Table 1 is called accounts Table 2 is called ...
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2answers
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MySQL - automatically update all references to specific table to use on delete cascade?

I have a specific table for one of my software packages on a MySQL 5.1 box which I need to drop a few hundred entries. These are user names with names in uppercase, the application is case specific ...
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1answer
598 views

Deleting 200M+ rows from InnoDB table

Basically, we have a table with the following structure: CREATE TABLE `reqs` ( `id` INT(10) NOT NULL AUTO_INCREMENT, `reqid` BIGINT(20) NOT NULL, `from` BIGINT(20) NOT NULL, `to` ...
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4answers
898 views

Delete the N oldest entries grouped by multiple columns

I´d like to delete the oldest entries of my database, but in each category shall remain at least N words of each char. Structure of TABLE words id | word | char | category For example I have the ...
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594 views

Will deleting data in master automatically delete data in slave?

I have data replication setup on MySQL. If I delete data on the master, will replication know data was deleted and automatically delete the same data on slave?
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Postgresql revert back database value

I have postgresql database. My table name is tblvoippolicy. Now, problem is by mistake i have deleted some records from table. When I get the data file using following commands. select * from ...
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2answers
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MySQL Trigger Query Not Deleting As Expected

I have a test database as shown below. If date is updated in tbl1, I would like for a trigger to fire that removes all entries from tbl2 where tbl1.host = tbl2.host2 AND tbl1.date = NEW.date. This is ...
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Cascade deletes from multiple tables

I have a fairly standard restaurant model with a restaurant table in a PostgreSQL DB. All restaurants have ratings (which consist of average, vote_count and vote_sum) but in order to avoid repeating ...
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Deleting large amounts of cascading records with minimal locking

I'm looking for a strategy to purge large amounts of logically deleted data from a MySQL database. The deleted records are in a relatively small table, but are referred to with many ON DELETE CASACDE ...
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How is it possible that two deletes give a deadlock, if they do have different primary key data

I am getting a deadlock by the same delete stored procedures that is called by two different threads for deleting two concurrent records. The deadlock happened on the primary key index of the X ...
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DELETE from Linked Server table using OPENQUERY and dynamic criteria

I'm attempting to run a DELETE statement from my local SQL Server to delete appropriate records from a table in my remote linked server using OPENQUERY(). I'm using the following code, but it seems ...
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1answer
776 views

Error deleting more than 1 row

I have a stored procedure that is supposed to delete several rows from a table. It does not work and gives me the error: The transaction ended in the trigger. The batch has been aborted I tried ...
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1answer
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Inherit audit columns and triggers

Background I have a database with dozens of tables, some of which should have audit columns. Problem I'd like to avoid the drudgery of creating audit columns manually, and write the update and ...
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1answer
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clustered and covering index ignored on delete statement. Table scan occurs

Why would SQL Server 2005 find it more efficient to perform a table scan instead of using the available clustered index on the primary key (and only the primary key)? DISCLAIMER: There is also a ...
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2answers
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remove duplicate rows in mysql table that does not contain primary key

I have a table item having just one column name:- name ----- toys shirt mobile Shirt speaker Toys .... .... I am trying to delete duplicate rows except one duplicated record with the help of below ...
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How can I delete repeated rows?

I have a system that gathers RSS from many sites including UTF-8 based sites (non-english sites). I have tried to avoid repeated rows but I have repeats in my table. RSS_items (id(auto_increment) ...
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speed up ghost cleanup

In SQL Server I have a table that is filled often and also gets deleted often. Because several threads write and erase data from that table I cannot even truncate it because there is always someone ...
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1answer
108 views

What is the equivalent of a “Certificate of Destruction” when using a cloud-hosted database?

We have a Rails application hosted by Heroku and using an Heroku Postgres database. Some of the information we store is considered to be sensitive by our users, and we've been asked if we can provide ...
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4answers
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MySQL: Keep the 10 most recent rows for each user

I have a table saving scores for a game that have 3 columns (more in practice, but it is easier for everyone this way): userid : the id of the user that got the score timestamp: the time the score ...
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How to delete rows from a table when we're joining and return data?

I have two queries: The first one is as below: SELECT * FROM batch bp INNER JOIN sender_log sl ON sl.id=bp.log_id AND bp.protocol='someprotocol' The second query is used to delete rows: ...
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Deleting data from a large table with replication

I need to delete all the rows from a given table. The table contains millions or records. The master database is being replicated to several slaves and I wish to do that without creating a replication ...
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3answers
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Do I need to reindex mysql table after bulk delete?

I have a table in MySQL with a lot of INSERT and SELECT at every second. And there is a bulk delete of some older data once in a day. Do I need to reindex the table after delete? I want to increase ...
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253 views

Soft delete to improve performance: all wrong?

A few years back I read soft delete would improve performance of deletion, because instead of actually removing the item and impact the clustered (and all other) indices, it would just change a value. ...
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1answer
222 views

Full table scan - high water mark

When doing a full-table scan, why does Oracle scan all the rows beneath the high-water mark? Doesn't it know that some of the rows have been deleted and that they shouldn't be scanned?
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1answer
247 views

Unable to delete a record in Mysql

Let's say I have table name Company with two columns cname, location. In the table I am having two records with cname |location Asmetric |Dallas Sophore |Washington on this table when I ...
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1answer
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Delete query does not appear to open space on the SQL Server

Our SQL Server (version 2012) is housed on a cloud server, for which we pay whenever we need additional space. We determined that we could delete some of the data to prevent the need for continually ...
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699 views

SQL Server : trigger FOR DELETE

I want to create a trigger, which does not delete a customer if his name is Peter. How can I do that? CREATE TRIGGER trgCUSTOMER ON customer FOR DELETE AS BEGIN IF (SELECT name FROM deleted) not ...
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1answer
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Delete from table where two of the three keys in another select

I have tableA which has 4 columns: IDA (bigint), IDB (int), IDC (varchar(255)) and comment (varchar(255)). The primary key is (IDA, IDB, IDC). I'm required to delete the records where the count of ...
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2k views

How to avoid locks by large transactions?

We have a large application running, that requires cleanup for performance reasons. This was however not forseen when designing the application. Basically, the delete is executed from a stored ...
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1k views

Approaches for deleting unnecessary records from tables

We have a database which stores the temperatures of 20 thermometer every 7 seconds. We want to delete all records in the way that every minute holds just one tempereature instead of 8 which are older ...
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what is the quickest way to delete duplicate rows?

I need to delete duplicate rows from a large table. what is the best way to achieve that? currently I use this algorithm: declare @t table ([key] int ) insert into @t select 1 insert into @t ...
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63 views

Query optimization in case of TIMESTAMPDIFF

I have a table where I need to delete all rows older than 5 hours. Currently I'm doing: delete from my_table where TIMESTAMPDIFF(HOUR, from_unixtime(round(created_on/1000)), now()) > 5 The ...
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What is the best way to purge data from a table with minimum damage to performance?

When you purge records from a database table, deleting them, you have impact on the logical and physical structure of the target table, as well as indexes and statistics. What maintenance should be ...