55a64ab8_PHP__Statistics___Manual_mysqlnd_statistics__Result_Set_Description
[Statistic] ps_prepared_once_executed [Scope] Connection [Notes] One of the ideas behind prepared statements is that the same query gets executed over and over again (with different parameters) and some parsing and other preparation work can be saved, if statement execution is split up in separate prepare and execute stages. The idea is to prepare once and cache results, for example, the parse tree to be reused during multiple statement executions. If you execute a prepared statement only once the two stage processing can be inefficient compared to normal queries because all the caching means extra work and it takes (limited) server resources to hold the cached information. Consequently, prepared statements that are executed only once may cause performance hurts. [Description] 
Number of prepared statements executed only one.
PHP: Statistics - Manual
Description