Using 2.3.3, here are the type of errors that crop up in error_log everyday.
[25-Jan-2008 08:37:35] WordPress database error MySQL server has gone away for query UPDATE wp_options SET option_value = '0' WHERE option_name = 'doing_cron'
[25-Jan-2008 09:23:19] WordPress database error MySQL server has gone away for query UPDATE wp_options SET option_value = '0' WHERE option_name = 'doing_cron'
[26-Jan-2008 00:03:54] WordPress database error MySQL server has gone away for query UPDATE wp_options SET option_value = '0' WHERE option_name = 'doing_cron'
[26-Jan-2008 00:04:29] WordPress database error MySQL server has gone away for query SELECT * FROM wp_posts, wp_postmeta WHERE wp_posts.ID = wp_postmeta.post_id AND wp_postmeta.meta_key = '_pingme' LIMIT 1
[26-Jan-2008 00:04:29] WordPress database error MySQL server has gone away for query SELECT * FROM wp_posts, wp_postmeta WHERE wp_posts.ID = wp_postmeta.post_id AND wp_postmeta.meta_key = '_encloseme' LIMIT 1
[26-Jan-2008 00:04:29] WordPress database error MySQL server has gone away for query SELECT ID FROM wp_posts WHERE CHAR_LENGTH(TRIM(to_ping)) > 7 AND post_status = 'publish'
[26-Jan-2008 00:05:09] WordPress database error MySQL server has gone away for query SELECT * FROM wp_posts, wp_postmeta WHERE wp_posts.ID = wp_postmeta.post_id AND wp_postmeta.meta_key = '_pingme' LIMIT 1
[26-Jan-2008 00:05:09] WordPress database error MySQL server has gone away for query SELECT * FROM wp_posts, wp_postmeta WHERE wp_posts.ID = wp_postmeta.post_id AND wp_postmeta.meta_key = '_encloseme' LIMIT 1
[26-Jan-2008 00:05:09] WordPress database error MySQL server has gone away for query SELECT ID FROM wp_posts WHERE CHAR_LENGTH(TRIM(to_ping)) > 7 AND post_status = 'publish'
[26-Jan-2008 00:05:47] WordPress database error MySQL server has gone away for query SELECT * FROM wp_posts, wp_postmeta WHERE wp_posts.ID = wp_postmeta.post_id AND wp_postmeta.meta_key = '_pingme' LIMIT 1
[26-Jan-2008 00:05:47] WordPress database error MySQL server has gone away for query SELECT * FROM wp_posts, wp_postmeta WHERE wp_posts.ID = wp_postmeta.post_id AND wp_postmeta.meta_key = '_encloseme' LIMIT 1
[26-Jan-2008 00:05:47] WordPress database error MySQL server has gone away for query SELECT ID FROM wp_posts WHERE CHAR_LENGTH(TRIM(to_ping)) > 7 AND post_status = 'publish'
.................