[Done v1.3.8] Database Cache Bug

[Ben]

There appears to be a reproducible problem with the way Zen Cart 1.3.6 handles the database cache. I discovered this while trying to write a custom shipping module. I have included a generic shipping module that should be able to reproduce the problem.

--- THE PROBLEM ---
When a shipping module is installed that enters a large number of keys (more than 250) into the “Configuration” table, accessing any of the products pages in the catalog returns the following errors.

Warning: Variable passed to each() is not an array or object in /home/turfmach/public_html/catalog_test/includes/classes/db/mysql/query_factory.php on line 114

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /home/turfmach/public_html/catalog_test/includes/classes/db/mysql/query_factory.php:114) in /home/turfmach/public_html/catalog_test/includes/functions/sessions.php on line 102

Warning: Cannot modify header information - headers already sent by (output started at /home/turfmach/public_html/catalog_test/includes/classes/db/mysql/query_factory.php:114) in /home/turfmach/public_html/catalog_test/includes/init_includes/init_templates.php on line 78

1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'EXPECTED_PRODUCTS_SORT limit MAX_DISPLAY_UPCOMING_PRODUCT' at line 9 in:
[select p.products_id, pd.products_name, products_date_available as date_expected from products p, products_description pd, products_to_categories p2c, categories c where p.products_id = p2c.products_id and p2c.categories_id = c.categories_id and c.parent_id = '1' and p.products_date_available >=20061107 and p.products_id = pd.products_id and p.products_status = 1 and pd.language_id = '1' order by EXPECTED_PRODUCTS_FIELD EXPECTED_PRODUCTS_SORT limit MAX_DISPLAY_UPCOMING_PRODUCTS]

These errors are only returned when the SQL_CACHE_METHOD in the following files are set to “database”.
catalog/includes/configure.php
catalog/admin/includes/configure.php

When set to “none” or “file” everything works fine.

I have tested this on a fresh install of Zen Cart v1.3.6

I suspect that there may be a problem with the “Execute” function in query_factory.php.

--- TO TEST ---
1. Install Zen Cart v1.3.6 using database cache
2. Unzip and copy the attached files to their corresponding directories
3. Configure "Country" and "Postcode" in Admin > Configuration > Shipping/Packaging
4. Install MyCourier in Admin > Modules > Shipping
5. Go to the catalog and browse to any products page and the above errors should occur

These errors can be removed by either:
1. Uninstalling MyCourier
2. Changing the SQL_CACHE_METHOD to "none" or "file"
3. Using fewer keys in the shipping module (In my testing less than about 230 keys and the errors disappear. But this seems to vary)

[Kim]

What version of php are you using?

[JeffD]

Just a comment regarding this error...

Warning: Variable passed to each() is not an array or object in /home/turfmach/public_html/catalog_test/includes/classes/db/mysql/query_factory.php on line 114

We are using the 'file' method, yet every one in a while (maybe once a week) we get an errorlog write such as the above. I have never been able to track down where this comes from and not certain it is related to your problem but thought I should mention it.

We are using Windows 2000, MySQL 5.0.21, Apache/2.2.2 (Win32) mod_ssl/2.2.2 OpenSSL/0.9.8b mod_jk/1.2.15 PHP/5.1.4

Jeff

[Ben]

PHP Version: 4.4.2 (Zend: 1.3.0)
MySQL 5.0.24-standard
Server OS: Linux 2.6.9-42.0.3.ELsmp

[Ben]

Hi JeffD, thanks for your comments.

I'm not familiar with the "errorlog" you mentioned. Are you referring to the one in cPanel or does Zen Cart have its own error log?

[DrByte]

As of v1.3.x, Zen Cart does not manage an errorlog.
The reference is most likely to the Apache errorlog (which, yes, is accessible via cPanel on cPanel-equipped hosts).

[JeffD]

Actually the errorlog I was referencing was the PHP errors log which can be enabled by setting the path and name of the file in the php.ini file, and then enabling the flag.

Jeff

[ronwong]

I salute you for this bug contribution. I have used database session cacheing for all my shops till I upgrade to 1.36 and heck, I was at deadend with these strange errors. Changed to file cacheing and all the problem's gone. The error is exactly the same. I dont know what is happening behind nor can I trouble shoot, but your bug report definitely solved my problem

[DrByte]

The *real* fix/resolution is here:
http://www.zen-cart.com/forum/showth...357#post378357