In actual coding, if we want to view and operate memory, the first thing many programmers think of is
The following is PHP memory_get_usage() Usage example:
The comments after the above programs represent their output (unit: byte(s)), which is the memory used by the PHP script at that time (excluding the memory occupied by the memory_get_usage() function itself)
As can be seen from the above example, in order to reduce memory usage, you can use the PHP unset() function to delete variables that are no longer needed. Similar ones include: PHP mysql_free_result() function, which can clear the result set obtained by querying the database that is no longer needed, so that more available memory can be obtained.
PHP memory_get_usage() can also have a parameter, $real_usage, whose value is a Boolean value. The default is FALSE, which means that the obtained memory usage does not include the memory occupied by this function (PHP memory manager); when set to TRUE, the obtained memory does not include the memory occupied by this function (PHP memory manager).
So in actual programming, you can use PHP memory_get_usage() to compare the memory occupied by each method to choose which method takes up less memory.
Commonly used tests:
Use microtime function to analyze program execution time
memory_get_usage can analyze memory footprint
For SQL efficiency, you can use slow query to view log analysis
SQL finds bottlenecks and uses EXPLAIN to analyze