Version: 1.00, by s.molinari
Developer Last Online: Sep 2018
Version: 2.3.x
Rating:
Released: 02-23-2003
Last Update: Never
Installs: 12
No support by the author.
Hi vB Troopers,
*****************
* Hack Idea:
*****************
This hack is designed to improve 2 things:
1. Prevent duplicate attachments altogether.
2. Speed up the query for duplicates and avoid errors.
What does vB do now?
---------------------------------
If you have "Allow Duplicate Images" set to "No" in your attachments options and your database has a very large amount of attachments, at worst, the server will timeout or the query to check for duplicate attachments takes an extreme amount of time. The duplicates query also checks only for duplicates from a particular user so actually it is possible to have duplicate attachments in the database.
What does vB do differently after the hack?
------------------------
With the hack installed, each attachment receives a hash which is stored in the attachment table. This hash is then used to find duplicate attachments regardless of whether or not the attachment is from the same user or not. So duplicate attachments are not possible.
Why vB works faster with this hack?
------------------------------------
Since the hash field and not the actual file content is being compared, then much less server resources are needed for MySql to run the query. Also the hash field is indexed. This in turn speeds up the saving of the attachments when checking for duplicates.
Please be aware that this hack alters the database and when carried out incorrectly, could cause data loss. Installation is at your own risk.
That said, enjoy!
Scott
This hack was written by pogo.
Also note, a system similiar to this will be part of vB3, so no need to ask if it will be added.
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This modification may not be copied, reproduced or published elsewhere without author's permission.
lifesourcerec - The @ prevents it from outputting an error if the function fails. It was added in there in vb 2.2.7 i believe (i can remember from when i upgraded)
Originally posted by TranceMaster how would i go about removing this hack
after installing it, my forum has been going very very slow
how do i remove these queries?
-------------------------------------------------------------------------------
ALTER TABLE attachment ADD hash VARCHAR(32) DEFAULT '0' NOT NULL;
-------------------------------------------------------------------------------
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UPDATE attachment SET hash = md5(filedata);
-------------------------------------------------------------------------------
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ALTER TABLE attachment ADD INDEX(hash);
-------------------------------------------------------------------------------
hope sum1 can help
thanks
If you use PHPMyAdmin you can remove the hash field and the index just by clicking the links in PHPMyAdmin.
In the table listing menu click attachment.
Then in the fields table click delete in the hash row.
And last click delete a little below in the index area.
If you use PHPMyAdmin you can remove the hash field and the index just by clicking the links in PHPMyAdmin.
In the table listing menu click attachment.
Then in the fields table click delete in the hash row.
And last click delete a little below in the index area.
tried that aswell, yet for some reason the forum is going very very slow.
dont get me wrong, great hack, i would just like 2 tottaly remove it now,
if (!$allowduplicates) {
if ($result=$DB_site->query_first("SELECT attachmentid
FROM attachment
WHERE hash = '".addslashes($attachmenthash)."'")) {
$attachmentid = $result[attachmentid];
return $attachmentid;
}
$DB_site->query("INSERT INTO attachment (attachmentid,userid,dateline,filename,filedata,visible,hash) VALUES (NULL,$bbuserinfo[userid],".time().",'".addslashes($attachment_name)."','".addslashes($filestuff)."','$visible','".addslashes($attachmenthash)."')");
$attachmentid=$DB_site->insert_id();
I guess there was just one } to much.
Correct me if i am wrong Molinari...