Database was suspended due too overload...

Hello, I wonder if anyone can make sense of this, Ive had this shop running for over 2 years without any problems at all until this morning where as I received this email from the hosts saying the database was suspended and has to be optimized, but I dont understand what is causing the overload from these logs...

| 1102146 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 4 | Opening tables | select products_description
| 1102147 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 34 | closing tables | select sale_specials_condition, sale_deduction_value, sale_deduction_type from zen_salemaker_sales w |
| 1102189 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 23 | Opening tables | select products_id, products_quantity_order_max from zen_products where products_id = '1939' |
| 1102190 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 4 | Opening tables | select products_id, products_quantity_order_max from zen_products where products_id = '1783' |
| 1102191 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 141 | removing tmp table | select banners_id, banners_title, banners_image, banners_html_text, banners_open_new_windows, banner |
| 1102250 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 107 | closing tables | select options_id, price_prefix, options_values_price, attributes_display_only, attributes_price_bas |
| 1102271 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 144 | closing tables | select products_tax_class_id, products_price, products_priced_by_attribute, product_is_free, product |
| 1104303 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 1 | Opening tables | select banners_id, banners_title, banners_image, banners_html_text, banners_open_new_windows, banner |
| 1104316 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 21 | Opening tables | select products_id, products_quantity_order_max from zen_products where products_id = '634' |
| 1104330 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 136 | Opening tables | select products_id, products_quantity_order_min from zen_products where products_id = '1939' |
| 1104338 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 30 | closing tables | select options_id, price_prefix, options_values_price, attributes_display_only, attributes_price_bas |
| 1104383 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 13 | Opening tables | select count(*) as total
| 1104385 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 127 | closing tables | update zen_banners_history set banners_shown = banners_shown +1 where banners_id = '21' and date_for |
| 1104489 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 22 | Opening tables | select products_type from zen_products where products_id='1922' |
| 1104506 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 22 | closing tables | update zen_banners_history set banners_shown = banners_shown +1 where banners_id = '21' and date_for |
| 1104520 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 24 | closing tables | select pa.products_attributes_id
| 1104539 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 34 | Opening tables | insert into zen_db_cache set cache_entry_name = 'zc_1bb761a3a593e628e1eddaeb1321bda4',
| 1104566 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 15 | Opening tables | select startdate, counter, session_counter from zen_counter_history where startdate='20100218' |
| 1104607 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 22 | closing tables | SELECT categories_description
| 1106710 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 4 | Opening tables | select * from zen_db_cache where cache_entry_name = 'zc_1bb761a3a593e628e1eddaeb1321bda4' |
| 1106749 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 136 | closing tables | SELECT p.products_id, p.products_type, pd.products_name, p.products_image, p.products_price,
| 1106751 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 34 | closing tables | select c.categories_id, cd.categories_name, c.parent_id, c.categories_image
| 1106811 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 108 | closing tables | select b.banners_id, b.expires_date, b.expires_impressions,
| 1106812 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 12 | closing tables | update zen_whos_online
| 1106852 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 13 | Copying to tmp table | select c.categories_id, cd.categories_name, c.parent_id, c.categories_image
| 1106900 | marketpl_zc1 | localhost | marketpl_zc1 | Sleep | 0 | | |
| 1106903 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 136 | closing tables | insert into zen_db_cache set cache_entry_name = 'zc_6ec65decb95a7741ada473af0fde76e1',
| 1106922 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 108 | closing tables | delete from zen_whos_online
| 1110911 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 32 | Opening tables | insert into zen_db_cache set cache_entry_name = 'zc_6ec65decb95a7741ada473af0fde76e1',
| 1112971 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 21 | Opening tables | delete from zen_db_cache where cache_entry_name = 'zc_6ec65decb95a7741ada473af0fde76e1' |
| 1112998 | marketpl_zc1 | localhost | marketpl_zc1 | Query | 50 | Opening tables | select * from zen_db_cache where cache_entry_name = 'zc_6ec65decb95a7741ada473af0fde76e1' |

Just wondered if anyone else can make sense of this, it is something that happened in the early hours of hte morning when there is the least amount of activity, so im really confused.

If anyone can spread any light it would be greatly appreciated
Thank you
Sam

Maybe zen_db_cache table got too big? Clear it of all contents by executing MySQL command:

TRUNCATE TABLE zen_db_cache

If You don't know how to do it here's my screencast:
http://www.data-diggers.com/index.php/2009/12/how-to-execute-show-create-table-in-phpmyadmin/
In above screencast I showed how to execute 'SHOW CREATE TABLE[...]' command, but just change it to command above.

Thank you Data_digger, will give that a go :)

Ive also added your query cache which looks to be a useful upload :D