int sqlite3_db_release_memory(sqlite3*);
The sqlite3_db_release_memory(D) interface attempts to free as much heap memory as possible from database connection D. Unlike the sqlite3_release_memory() interface, this interface is in effect even when the SQLITE_ENABLE_MEMORY_MANAGEMENT compile-time option is omitted.
See also: sqlite3_release_memory()
See also lists of Objects, Constants, and Functions.
SQLite is in the Public Domain.
https://sqlite.org/c3ref/db_release_memory.html