2

[MySQL] Deleting/Updating Rows Common To 2 Tables – Speed And Slave Lag Considerations


Posted by Artem Russakovskii on May 11th, 2009 in Databases, Programming

Introduction

A question I recently saw on Stack Overflow titled Faster way to delete matching [database] rows? prompted me to organize my thoughts and observations on the subject and quickly jot them down here.

Here is the brief description of the task: say, you have 2 MySQL tables a and b. The tables contain the same type of data, for example log entries. Now you want to delete all or a subset of the entries in table a that exist in table b.

Solutions Suggested By Others

DELETE FROM a WHERE EXISTS (SELECT b.id FROM b WHERE b.id = a.id);
 
DELETE a

…

Read the rest of this article »

3

How To Delete All Messages From A Folder In Pine


Posted by Artem Russakovskii on March 23rd, 2008 in Linux

Pine is a UNIX command line mail application. So how do you delete all messages in a folder?

The combination is 

1

; A A D

If after pressing ; you see

1

[Command ";" not defined for this screen. Use ? for help]

then you don't have a check in the "Enable aggregate command set" settings checkbox. To enable it, go to the main menu (M) -> Setup (S) -> Config (C) and scroll down to "Enable aggregate command set". Then press X (to check it), E (Exit). Now repeat the above….

Read the rest of this article »