Answer by Chase Seibert for Per-request cache in Django?

Years later, a super hack to cache SELECT statements inside a single Django request. You need to execute the patch() method from early on in your request scope, like in a piece of middleware.

from threading import localimport itertoolsfrom django.db.models.sql.constants import MULTIfrom django.db.models.sql.compiler import SQLCompilerfrom django.db.models.sql.datastructures import EmptyResultSetfrom django.db.models.sql.constants import GET_ITERATOR_CHUNK_SIZE_thread_locals = local()def get_sql(compiler):''' get a tuple of the SQL query and the arguments '''    try:        return compiler.as_sql()    except EmptyResultSet:        pass    return ('', [])def execute_sql_cache(self, result_type=MULTI):    if hasattr(_thread_locals, 'query_cache'):        sql = get_sql(self)  # ('SELECT * FROM ...', (50)) <= sql string, args tuple        if sql[0][:6].upper() == 'SELECT':            # uses the tuple of sql + args as the cache key            if sql in _thread_locals.query_cache:                return _thread_locals.query_cache[sql]            result = self._execute_sql(result_type)            if hasattr(result, 'next'):                # only cache if this is not a full first page of a chunked set                peek = result.next()                result = list(itertools.chain([peek], result))                if len(peek) == GET_ITERATOR_CHUNK_SIZE:                    return result            _thread_locals.query_cache[sql] = result            return result        else:            # the database has been updated; throw away the cache            _thread_locals.query_cache = {}    return self._execute_sql(result_type)def patch():''' patch the django query runner to use our own method to execute sql '''    _thread_locals.query_cache = {}    if not hasattr(SQLCompiler, '_execute_sql'):        SQLCompiler._execute_sql = SQLCompiler.execute_sql        SQLCompiler.execute_sql = execute_sql_cache

The patch() method replaces the Django internal execute_sql method with a stand-in called execute_sql_cache. That method looks at the sql to be run, and if it's a select statement, it checks a thread-local cache first. Only if it's not found in the cache does it proceed to execute the SQL. On any other type of sql statement, it blows away the cache. There is some logic to not cache large result sets, meaning anything over 100 records. This is to preserve Django's lazy query set evaluation.