multiple simultaneous DBI connections?
I am currently looking at building a Perl object to handle data from a a database. I'm not really sure if it is best to have one connection to MySQL and let the object just deal with its own properties. Or to allow the object to initiate a DBI connection each time an instance of the object is created, and to disconnect() using garbage disposal. Although the object initially would only have one instance per script, I can't help feeling it is a bad idea. Any thoughts welcome, and greatly appreciated, Tom Norwood. This email has been scanned for viruses by NetBenefit using Sophos anti-virus technology - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
RE: multiple simultaneous DBI connections?
Paul, I guess I would see the fact that the script would hold the connection to MySQL for a shorter period of time, as the most obvious advantage. As far as OO programming goes the integration of DBI into my object would assure that a connection to the database would be established automatically before the object's methods try to initiate calls to the MySQL server. Also a similar point goes for disconnect()-ing from the server, my object would 'know' that a connection is available if it exists! So no additional coding would be required within my object's methods. Tom Norwood. -Original Message- From: Paul DuBois [mailto:[EMAIL PROTECTED] Sent: 13 March 2003 15:14 To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: Re: multiple simultaneous DBI connections? At 14:47 + 3/13/03, Tom Norwood wrote: I am currently looking at building a Perl object to handle data from a a database. I'm not really sure if it is best to have one connection to MySQL and let the object just deal with its own properties. Or to allow the object to initiate a DBI connection each time an instance of the object is created, and to disconnect() using garbage disposal. Although the object initially would only have one instance per script, I can't help feeling it is a bad idea. It's difficult to give you an answer each way unless you tell us why you suspect it might be a bad idea. Certainly you'll use somewhat more resources on both the client and server ends if you maintain multiple open connections. What would you see as an advantage to having multiple connections? Any thoughts welcome, and greatly appreciated, Tom Norwood. This email has been scanned for viruses by NetBenefit using Sophos anti-virus technology This email has been scanned for viruses by NetBenefit using Sophos anti-virus technology - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
RE: multiple simultaneous DIB connections?
Although my initial implementation would only deal with one instance of my object. There WOULD be simultaneous connections if two or more instances of my object existed at the same time. Tom Norwood. -Original Message- From: Paul DuBois [mailto:[EMAIL PROTECTED] Sent: 13 March 2003 16:23 To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: RE: multiple simultaneous DBI connections? At 15:47 + 3/13/03, Tom Norwood wrote: Paul, I guess I would see the fact that the script would hold the connection to MySQL for a shorter period of time, as the most obvious advantage. As far as OO programming goes the integration of DBI into my object would assure that a connection to the database would be established automatically before the object's methods try to initiate calls to the MySQL server. Also a similar point goes for disconnect()-ing from the server, my object would 'know' that a connection is available if it exists! So no additional coding would be required within my object's methods. Tom Norwood. Ah. I was misinterpreting your message, thinking you meant multiple *simultaneous* connections. With some database engines, you'd probably want to use a single connection and hold it open, because the overhead for connection setup/teardown is significant. With MySQL, that's not much of a factor in most cases. It has very efficient connection establishment. -Original Message- From: Paul DuBois [mailto:[EMAIL PROTECTED] Sent: 13 March 2003 15:14 To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: Re: multiple simultaneous DBI connections? At 14:47 + 3/13/03, Tom Norwood wrote: I am currently looking at building a Perl object to handle data from a a database. I'm not really sure if it is best to have one connection to MySQL and let the object just deal with its own properties. Or to allow the object to initiate a DBI connection each time an instance of the object is created, and to disconnect() using garbage disposal. Although the object initially would only have one instance per script, I can't help feeling it is a bad idea. It's difficult to give you an answer each way unless you tell us why you suspect it might be a bad idea. Certainly you'll use somewhat more resources on both the client and server ends if you maintain multiple open connections. What would you see as an advantage to having multiple connections? Any thoughts welcome, and greatly appreciated, Tom Norwood. This email has been scanned for viruses by NetBenefit using Sophos anti-virus technology This email has been scanned for viruses by NetBenefit using Sophos anti-virus technology - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
Another 'Too many connections' question...
A couple of weeks ago I came across this error which effectively closed down our site. Two things: (1) I am using Perl DBI to interface mySQL is there any way to effectively capture such errors and provide an alternate web page? I guess there has to be, but I experimented with the 'PrintError' and 'RaiseError' with little joy. (2) At present our MySQL needs are provided by our ISP by means of a shared server (dedicated to MySQL I think!). The 'max_connections' variable (SHOW VARIABLES) is currently set to 300, which seems a bit on low side for a server with 770 databases (SHOW DATABASES) with I don't know how many tables. What causes this error, 'any' connection, admin type connections, etc.? And does this error require a server/mysqld restart on the part of our ISP? They were typically unhelpful when I spoke to them (hope that's not due to ignorance.) Have been looking at dedicated hosting for a while now, but finding the cash and moreover the time to move is proving a slow process. Any help gratefully Rx'd, Tom. - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
Date Comparison Problem...
Just when I thought I was getting the hang of this mysql stuff, the simplest
of tasks
is causing me to think about pulling my hair out.
My table:
NEWS {
newsID (INT(3), AUTO-INCREMENT),
newsTitle (VARCHAR (50)),
newsText (BLOB),
newsDate (DATE)
}
I just want to filter OUT any rows that have a 'future' date value in
'newsDate' column.
(ie. Don't select any news that hasn't happened yet!)
Query, I gather the WHERE clause deals with -MM-DD formatted dates:
SELECT * FROM news
WHERE newsDate DATE_ADD(CUR_DATE(), INTERVAL 1 DAY)
ORDER BY newsDate DESC
If I take out the WHERE clause the whole table gets SELECT-ed, it works
fine:
SELECT * FROM news
ORDER BY newsDate DESC
Any assistance gratefully Rx'd. I have DuBois's MySQL, it's obviously too
good for me.
Also tried various searches on MySQL.com, with little joy, aahh!
Tom.
-
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ADD: Date Comparison Problem...
Very interesting addition to message...
Forgot to mention what the problem-query produces: Nothing.
Cheers,
Tom.
-Original Message-
From: Tom Norwood [mailto:[EMAIL PROTECTED]]
Sent: 27 July 2002 19:39
To: mysql-list
Subject: Date Comparison Problem...
Just when I thought I was getting the hang of this mysql stuff, the simplest
of tasks
is causing me to think about pulling my hair out.
My table:
NEWS {
newsID (INT(3), AUTO-INCREMENT),
newsTitle (VARCHAR (50)),
newsText (BLOB),
newsDate (DATE)
}
I just want to filter OUT any rows that have a 'future' date value in
'newsDate' column.
(ie. Don't select any news that hasn't happened yet!)
Query, I gather the WHERE clause deals with -MM-DD formatted dates:
SELECT * FROM news
WHERE newsDate DATE_ADD(CUR_DATE(), INTERVAL 1 DAY)
ORDER BY newsDate DESC
If I take out the WHERE clause the whole table gets SELECT-ed, it works
fine:
SELECT * FROM news
ORDER BY newsDate DESC
Any assistance gratefully Rx'd. I have DuBois's MySQL, it's obviously too
good for me.
Also tried various searches on MySQL.com, with little joy, aahh!
Tom.
-
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http://www.mysql.com/manual.php (the manual)
http://lists.mysql.com/ (the list archive)
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To unsubscribe, e-mail [EMAIL PROTECTED]
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