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MXS-1310: Detect implicit database usage

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When the current database is implicitly used in a query that also uses an
explicit database, it must be routed to the shard which has the current
database.

As cross-shard joins are not supported, the safest, and possibly the most
expected course of action to take, is to route it to the so-called default
shard. The default shard is the shard that contains the database that is
currently set as the active database with a COM_INIT_DB, a text protocol
USE <database> query or it was set at connection time.
This commit is contained in:
Markus Mäkelä 2017-07-04 23:15:23 +03:00
parent 5ed6483f01
commit 0c33572a96
1 changed files with 20 additions and 1 deletions
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21
server/modules/routing/schemarouter/schemarouter.c
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@ -459,11 +459,30 @@ char* get_shard_target_name(ROUTER_INSTANCE* router,
char** dbnms = NULL;
char* rval = NULL, *query, *tmp = NULL;
bool has_dbs = false; /**If the query targets any database other than the current one*/
bool uses_implicit_databases = false;
dbnms = qc_get_database_names(buffer, &sz);
dbnms = qc_get_table_names(buffer, &sz, true);
for (i = 0; i < sz; i++)
{
if (strchr(dbnms[i], '.') == NULL)
{
uses_implicit_databases = true;
}
MXS_FREE(dbnms[i]);
}
MXS_FREE(dbnms);
HASHTABLE* ht = client->shardmap->hash;
if (uses_implicit_databases)
{
MXS_INFO("Query implicitly uses the current database");
return (char*)hashtable_fetch(ht, client->current_db);
}
dbnms = qc_get_database_names(buffer, &sz);
if (sz > 0)
{
for (i = 0; i < sz; i++)