Add an error when attempting to create foreign keys

Summary:
Currently if you attempt to create foreign keys when using the RocksDB engine no error is generated and the foreign key constraint is ignore (though a key is created).  Add an error so that this will not be allowed - any create table (or alter table) that adds a constraint will generate an error.

Issue 205

Test Plan: MTR

Reviewers: yoshinorim, hermanlee4

Reviewed By: hermanlee4

Subscribers: webscalesql-eng

Differential Revision: https://reviews.facebook.net/D56703

mysql-test/suite/rocksdb/r/foreign_key.result

@@ -0,0 +1,25 @@
+DROP TABLE IF EXISTS t1, t2;
+CREATE TABLE t1 (b INT PRIMARY KEY);
+CREATE TABLE t2 (a INT NOT NULL, b INT NOT NULL, FOREIGN KEY (b) REFERENCES t1(b));
+ERROR 42000: MyRocks does not currently support foreign key constraints
+CREATE TABLE t2 (a INT NOT NULL, bforeign INT NOT NULL);
+DROP TABLE t2;
+CREATE TABLE t2 (a INT NOT NULL, foreignkey INT NOT NULL);
+DROP TABLE t2;
+CREATE TABLE t2 (a INT NOT NULL, bforeign INT not null, FOREIGN KEY (bforeign) REFERENCES t1(b));
+ERROR 42000: MyRocks does not currently support foreign key constraints
+CREATE TABLE t2 (a INT NOT NULL, b INT NOT NULL);
+ALTER TABLE t2 ADD FOREIGN KEY (b) REFERENCES t1(b);
+ERROR 42000: MyRocks does not currently support foreign key constraints
+DROP TABLE t2;
+CREATE TABLE t2 (a INT NOT NULL);
+ALTER TABLE t2 ADD bforeign INT NOT NULL;
+DROP TABLE t2;
+CREATE TABLE t2 (a INT NOT NULL);
+ALTER TABLE t2 ADD foreignkey INT NOT NULL;
+DROP TABLE t2;
+CREATE TABLE t2 (a INT NOT NULL);
+ALTER TABLE t2 ADD bforeign INT NOT NULL, ADD FOREIGN KEY (bforeign) REFERENCES t1(b);
+ERROR 42000: MyRocks does not currently support foreign key constraints
+DROP TABLE t2;
+DROP TABLE t1;

mysql-test/suite/rocksdb/t/foreign_key.test

@@ -0,0 +1,45 @@
+--disable_warnings
+DROP TABLE IF EXISTS t1, t2;
+--enable_warnings
+
+CREATE TABLE t1 (b INT PRIMARY KEY);
+
+# Try simple foreign key - should fail
+--error ER_NOT_SUPPORTED_YET
+CREATE TABLE t2 (a INT NOT NULL, b INT NOT NULL, FOREIGN KEY (b) REFERENCES t1(b));
+
+# Try simple valid syntax with 'foreign' as part - should succeed
+CREATE TABLE t2 (a INT NOT NULL, bforeign INT NOT NULL);
+DROP TABLE t2;
+
+# Try simple valid syntax with 'foreign' and 'key' as part (with no space) - should succeed
+CREATE TABLE t2 (a INT NOT NULL, foreignkey INT NOT NULL);
+DROP TABLE t2;
+
+# Try with valid id containing 'foreign' and then a foreign key - should fail
+--error ER_NOT_SUPPORTED_YET
+CREATE TABLE t2 (a INT NOT NULL, bforeign INT not null, FOREIGN KEY (bforeign) REFERENCES t1(b));
+
+CREATE TABLE t2 (a INT NOT NULL, b INT NOT NULL);
+# Alter with foreign key - should fail
+--error ER_NOT_SUPPORTED_YET
+ALTER TABLE t2 ADD FOREIGN KEY (b) REFERENCES t1(b);
+DROP TABLE t2;
+
+# Alter with valid syntax that contains 'foreign' - should succeed
+CREATE TABLE t2 (a INT NOT NULL);
+ALTER TABLE t2 ADD bforeign INT NOT NULL;
+DROP TABLE t2;
+
+# Alter with valid syntax that contains 'foreign' and 'key' (no space) - should succeed
+CREATE TABLE t2 (a INT NOT NULL);
+ALTER TABLE t2 ADD foreignkey INT NOT NULL;
+DROP TABLE t2;
+
+# Alter with valid syntax that contains 'foreign' and then foreign key - should fail
+CREATE TABLE t2 (a INT NOT NULL);
+--error ER_NOT_SUPPORTED_YET
+ALTER TABLE t2 ADD bforeign INT NOT NULL, ADD FOREIGN KEY (bforeign) REFERENCES t1(b);
+DROP TABLE t2;
+
+DROP TABLE t1;

storage/rocksdb/CMakeLists.txt

@@ -35,6 +35,7 @@ SET(ROCKSDB_SOURCES
   rdb_i_s.cc rdb_i_s.h
   rdb_perf_context.cc rdb_perf_context.h
   rdb_mutex_wrapper.cc rdb_mutex_wrapper.h
+  rdb_utils.cc rdb_utils.h
   ${ROCKSDB_LIB_SOURCES}
 )
 

storage/rocksdb/ha_rocksdb.cc

@@ -4114,6 +4114,61 @@ int rocksdb_normalize_tablename(const char *tablename,
   return 0;
 }
 
+/*
+  Check to see if the user's original statement includes foreign key
+  references
+*/
+bool ha_rocksdb::contains_foreign_key(THD* thd)
+{
+  bool success;
+  const char* str = thd_query_string(thd)->str;
+
+  DBUG_ASSERT(str != nullptr);
+
+  while (*str != '\0')
+  {
+    // Scan from our current pos looking for 'FOREIGN'
+    str = rdb_find_in_string(str, "FOREIGN", &success);
+    if (!success)
+    {
+      return false;
+    }
+
+    // Skip past the found "FOREIGN'
+    str = rdb_check_next_token(&my_charset_bin, str, "FOREIGN", &success);
+    DBUG_ASSERT(success);
+
+    if (!my_isspace(&my_charset_bin, *str))
+    {
+      return false;
+    }
+
+    // See if the next token is 'KEY'
+    str = rdb_check_next_token(&my_charset_bin, str, "KEY", &success);
+    if (!success)
+    {
+      continue;
+    }
+
+    // See if the next token is '('
+    str = rdb_check_next_token(&my_charset_bin, str, "(", &success);
+    if (!success)
+    {
+      // There is an optional index id after 'FOREIGN KEY', skip it
+      str = rdb_skip_id(&my_charset_bin, str);
+
+      // Now check for '(' again
+      str = rdb_check_next_token(&my_charset_bin, str, "(", &success);
+    }
+
+    // If we have found 'FOREIGN KEY [<word>] (' we can be confident we have
+    // a foreign key clause.
+    return success;
+  }
+
+  // We never found a valid foreign key clause
+  return false;
+}
 
 /**
   @brief
@@ -4188,8 +4243,9 @@ int ha_rocksdb::create(const char *name, TABLE *table_arg,
   StringBuffer<256> strbuf;
   DBUG_ENTER("ha_rocksdb::create");
 
+  THD *thd = my_core::thd_get_current_thd();
+
   if (get_table_if_exists(name)) {
-    THD *thd = my_core::thd_get_current_thd();
     if (thd->lex->sql_command == SQLCOM_TRUNCATE) {
       if (delete_table(name)) {
         DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
@@ -4215,6 +4271,13 @@ int ha_rocksdb::create(const char *name, TABLE *table_arg,
   if (rocksdb_normalize_tablename(name, &strbuf))
     DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
 
+  if (contains_foreign_key(thd))
+  {
+    my_printf_error(ER_NOT_SUPPORTED_YET, "MyRocks does not currently support "
+        "foreign key constraints", MYF(0));
+    DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
+  }
+
   /*
     TODO(alexyang): Temporarily disable unique indexes support when there is no
     Primary Key

storage/rocksdb/ha_rocksdb.h

@@ -733,6 +733,8 @@ class ha_rocksdb: public handler
     __attribute__((__nonnull__, __warn_unused_result__));
   void read_thd_vars(THD *thd)
     __attribute__((__nonnull__));
+  bool contains_foreign_key(THD* thd)
+    __attribute__((__nonnull__, __warn_unused_result__));
 public:
   int index_init(uint idx, bool sorted) __attribute__((__warn_unused_result__));
   int index_end() __attribute__((__warn_unused_result__));