* Robert DiFalco <[EMAIL PROTECTED]> [06/04/30 03:09]: > Thanks Sergei, it's nice to know for sure. Do you know if there is any > documentation on how memory is used to store LOB data? For example, is > it a percentage of the total buffer pool size or is it allocated from > available memory un-allocated to the buffer pool size?
There is no streaming interface between the SQL layer and the storage engines layer. An engine operates with at least one column, not with a piece of a column (one exception is that we can use row IDs when walking through records in a join, in this case the LOB is not loaded). So, at first the LOB is assembled on the SQL layer (e.g. if you supply a LOB object in pieces via mysql_stmt_send_long_data), and then submitted to the storage layer. This means than when inserting a LOB the server creates at least two copies of it in memory - on the SQL layer and on the storage layer. If instead of mysql_stmt_send_long_data you use the text protocol and simply encode the LOB in the query text with mysql_real_escape_string, you get one more copy - in the text of the query itself, which is also kept in memory. -- -- Konstantin Osipov Software Developer, Moscow, Russia -- MySQL AB, www.mysql.com The best DATABASE COMPANY in the GALAXY -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
