Last summer my colleague Marko Mäkelä committed this seemingly
innocent performance fix for InnoDB in MySQL 5.6:
3581 Marko Makela 2011-08-10
Bug#12835650 VARCHAR maximum length performance impact
row_sel_field_store_in_mysql_format(): Do not pad the unused part of
the buffer reserved for a True VARCHAR column (introduced in 5.0.3).
Add Valgrind instrumentation ensuring that the unused part will be
Before this, buffers which were used to send VARCHARs from InnoDB to the MySQL server were padded with 0s if the string was shorter than specified by …