Re: [PHP] OT - database and indexes... but anyone please?
Rory Browne wrote: snipdeleting an index(a good index that is) would slow the db down in certain cases. Deleting a bad index would speed certain operations up. snip If the index in question happens to be a unique index or a primary key (really just a special case of index) - you could be breaking the logic of the table (allowing duplicates where there should be none). Pretty much as Rory (the other one) said: An index makes write operations slower and read operations faster. When you are doing bulk inserts to a table it is often a good idea to drop any index , populate the table and then re-index (for performance reasons). Regards Rory -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] OT - database and indexes... but anyone please?
Rory Browne wrote: snip If the index in question happens to be a unique index or a primary key (really just a special case of index) - you could be breaking the logic of the table (allowing duplicates where there should be none). Couldn't that only happen if you dropped a UNIQUE or PRIMARY KEY. Just to clarify, I only meant deleting, or dropping the index. Not the column that is indexed. snippety AFAIK, the unique /PK index is what avoids duplicates. So, if you dropped the index, while your existing data would still be duplicate-free, you would have no guarantees with regard to any data that you might write to the table after you had dropped the index. There was nothing wrong with your original answer(s) - I was just adding a few wrinkles to it as the OP did not provide much info in terms of the index that he was wishing to drop. Regards Rory -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] OT - database and indexes... but anyone please?
Gustav Wiberg mailto:[EMAIL PROTECTED] on Saturday, September 24, 2005 9:48 PM said: Thanx! Ok so I had to look up and down that message 3 or 4 times before I found this insignificant one line response. TRIM YOUR POSTS! -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] OT - database and indexes... but anyone please?
On 2005-09-26, Rory McKinley [EMAIL PROTECTED] wrote: If the index in question happens to be a unique index or a primary key (really just a special case of index) I thought a primary key is something defined at the logical, where an index is defined at the implementation level.. Therefore, a primary key can't be a special case of an index. -- Met vriendelijke groeten, Tim Van Wassenhove http://timvw.madoka.be -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] OT - database and indexes... but anyone please?
Hi there! This is not strictly PHP... but if there's anyone out there with good knowledge of indexes, please mail me off-list. My question: If I delete an index, what is the WORST thing that can happen? /G http://www.varupiraten.se/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] OT - database and indexes... but anyone please?
I'm not an expert on databases, and I haven't a notion of mailing you off-list, with information that could potentially benifit others as well, but from my understanding, deleting an index(a good index that is) would slow the db down in certain cases. Deleting a bad index would speed certain operations up. On 9/24/05, Gustav Wiberg [EMAIL PROTECTED] wrote: Hi there! This is not strictly PHP... but if there's anyone out there with good knowledge of indexes, please mail me off-list. My question: If I delete an index, what is the WORST thing that can happen? /G http://www.varupiraten.se/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] OT - database and indexes... but anyone please?
- Original Message - From: Rory Browne [EMAIL PROTECTED] To: Gustav Wiberg [EMAIL PROTECTED] Cc: PHP General php-general@lists.php.net Sent: Sunday, September 25, 2005 1:26 AM Subject: Re: [PHP] OT - database and indexes... but anyone please? I'm not an expert on databases, and I haven't a notion of mailing you off-list, with information that could potentially benifit others as well, but from my understanding, deleting an index(a good index that is) would slow the db down in certain cases. Deleting a bad index would speed certain operations up. On 9/24/05, Gustav Wiberg [EMAIL PROTECTED] wrote: Hi there! This is not strictly PHP... but if there's anyone out there with good knowledge of indexes, please mail me off-list. My question: If I delete an index, what is the WORST thing that can happen? /G http://www.varupiraten.se/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.11.6/111 - Release Date: 2005-09-23 Thanx! /G http://www.varupiraten.se/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
