I was using Maria 10.0.10 today and was banging my head against a wall for a few hours trying to figure out why my queries were missing the query cache.

http://bugs.mysql.com/bug.php?id=42197

I am working on a legacy PERL project that spawns many short-lived processes that connect to the database and do a single query before exiting.

my $dsn = "dbi:mysql:database=test";

my $dbh = DBI->connect($dsn, undef, undef, {RaiseError => 0, AutoCommit => 0});

# 1. Prepare query

# 2. Executed query (misses cache)

# 3. Process result

When DBI connects to the SQL server, the first thing it does is issue the "SET" command and then the query comes quickly behind it:

SET AUTOCOMMIT=0;

SELECT * FROM test;

When it then executes its query, it misses the query cache every time.