We did that too. For your http://imenno.ru

Good to hear you had found that. Just tested at js_composer v4.5.2 and that’s works fine. v.4.3 is works fine too. Hopefully that’s bug related only for js_composer v4.4.

Ok.
It this theme you should fix
js_composer/config/map.php on line 3533
and
wp-includes/taxonomy.php on line 3874

Just try with more then 50K records in the wp_term_taxonomy table. And you will get the same error as I had.
With memory_limit = 512M in php.ini its works. But this is not a good idea.
Definitely you need to test those two scripts with amount of data more then 100k, otherwise this isn’t a NewsMag theme this is personal Notes theme.

Log:
08-Jun-2015 20:00:39 UTC] PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 72 bytes) in /var/www/site.com/www/wp-includes/taxonomy.php on line 3874
[08-Jun-2015 20:12:12 UTC] PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 72 bytes) in /var/www/site.com/www/wp-content/plugins/js_composer/config/map.php on line 3533
[08-Jun-2015 20:12:15 UTC] PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 32 bytes) in /var/www/site.com/www/wp-content/plugins/js_composer/config/map.php on line 3531

Have fun.

At last we have a good debug file.
Here it is:
[08-Jun-2015 07:20:57 UTC] PHP Fatal error: require_once(): Failed opening required ‘td_block_template.php’ (include_path=’.:/usr/share/php:/usr/share/pear’) in /var/www/site.com/www/wp-content/themes/Newsmag/includes/wp_booster/td_wp_booster_functions.php on line 1206
[08-Jun-2015 07:20:57 UTC] PHP Warning: require_once(td_block_template.php): failed to open stream: No such file or directory in /var/www/site.com/www/wp-content/themes/Newsmag/includes/wp_booster/td_wp_booster_functions.php on line 1206

[08-Jun-2015 07:20:57 UTC] PHP Fatal error: require_once(): Failed opening required ‘td_block_template.php’ (include_path=’.:/usr/share/php:/usr/share/pear’) in /var/www/site.com/www/wp-content/themes/Newsmag/includes/wp_booster/td_wp_booster_functions.php on line 1206

# find . -name ‘td_block_template.php’
./themes/Newsmag/includes/wp_booster/td_block_template.php

Where should be this file -> td_block_template.php ?

I have an access to error.log file because I have a virtual debian server. Error.log is empty.
Theme is fine too, cause the same thing with standard WP themes.
There is a js_composer bug related with wp_term_taxonomy wordpress table. While wp_term_taxonomy is empty it is showing up the site. Continue to search the reason. Do we have a support to js_composer plugin owners ?

Having the same problem with js_composer.
After fresh WordPress install js_composer working just fine.
After inserting data from sql (posts) file showing blank page as site and Admin too.
When removing js_composer from plugin directory showing right Admin page again.
No other plugins installed. Debug is not showing when define(‘WP_DEBUG’, true);
Memory is 100 MB.
NewsMag is my theme.