Hi guys i'm reading query cache code, and i have some doubts...

mariadb-10.0.1 source:

1)PROTOCOL_LOCAL:

at line: 1412 (Query_cache::store_query)

we have this comment:

/* PROTOCOL_LOCAL results are not cached. */

what's PROTOCOL_LOCAL ? it's the unix socket? windows pipe? embedded? memcache? mysql? another thing like this? or it's the internal mariadb source running queries?

2)the query_size=0 (MDEV-4516)

i was reading at line 1680

if (is_disabled() || thd->locked_tables_mode || thd->variables.query_cache_type == 0)

goto err;

and line : 1694

DBUG_ASSERT(query_cache_size != 0); // otherwise cache would be disabled

why it's isn't used in query_cache_information plugin?

check that in line 1680 it test the "query_cache_type" too,

in MDEV-4516 report about size=0 we didn't tested this case!!!

3) i was at line 1886:

DBUG_PRINT("qcache", ("\

long %d, 4.1: %d, bin_proto: %d, more results %d, pkt_nr: %d, \

CS client: %u, CS result: %u, CS conn: %u, limit: %lu, TZ: 0x%lx, \

sql mode: 0x%llx, sort len: %lu, conncat len: %lu, div_precision: %lu, \

def_week_frmt: %lu, in_trans: %d, autocommit: %d",

is this the "primary key" of the query cache!?!?!?!?!?!?!

could we use a sha1 or another "primary key" method (index [] of the query in cache + '';'+ 5 bytes of a hash key to compare if the index still with the same query)

to easly show query entry "number", and allow a "delete from query_cache_information where key=xxx" function?

at line 1938 we have this maybe the query position on cache ("primary key of query cache")?:

DBUG_PRINT("qcache", ("Query have result 0x%lx", (ulong) query));

there's some more ideas about query cache information plugin at MDEV-4571, if anyone could read it =)

well that's all =]

Roberto Spadim