MDEV-10139 Support for SEQUENCE objects

Working features:
CREATE OR REPLACE [TEMPORARY] SEQUENCE [IF NOT EXISTS] name
    [ INCREMENT [ BY | = ] increment ]
    [ MINVALUE [=] minvalue | NO MINVALUE ]
    [ MAXVALUE [=] maxvalue | NO MAXVALUE ]
    [ START [ WITH | = ] start ] [ CACHE [=] cache ] [ [ NO ] CYCLE ]
    ENGINE=xxx COMMENT=".."
SELECT NEXT VALUE FOR sequence_name;
SELECT NEXTVAL(sequence_name);
SELECT PREVIOUS VALUE FOR sequence_name;
SELECT LASTVAL(sequence_name);

SHOW CREATE SEQUENCE sequence_name;
SHOW CREATE TABLE sequence_name;
CREATE TABLE sequence-structure ... SEQUENCE=1
ALTER TABLE sequence RENAME TO sequence2;
RENAME TABLE sequence TO sequence2;
DROP [TEMPORARY] SEQUENCE  [IF EXISTS] sequence_names

Missing features
- SETVAL(value,sequence_name), to be used with replication.
- Check replication, including checking that sequence tables are marked
  not transactional.
- Check that a commit happens for NEXT VALUE that changes table data (may
  already work)
- ALTER SEQUENCE. ANSI SQL version of setval.
- Share identical sequence entries to not add things twice to table list.
- testing insert/delete/update/truncate/load data
- Run and fix Alibaba sequence tests (part of mysql-test/suite/sql_sequence)
- Write documentation for NEXT VALUE / PREVIOUS_VALUE
- NEXTVAL in DEFAULT
  - Ensure that NEXTVAL in DEFAULT uses database from base table
- Two NEXTVAL for same row should give same answer.
- Oracle syntax sequence_table.nextval, without any FOR or FROM.
- Sequence tables are treated as 'not read constant tables' by SELECT; Would
  be better if we would have a separate list for sequence tables so that
  select doesn't know about them, except if refereed to with FROM.

Other things done:
- Improved output for safemalloc backtrack
- frm_type_enum changed to Table_type
- Removed lex->is_view and replaced with lex->table_type. This allows
  use to more easy check if item is view, sequence or table.
- Added table flag HA_CAN_TABLES_WITHOUT_ROLLBACK, needed for handlers
  that want's to support sequences
- Added handler calls:
 - engine_name(), to simplify getting engine name for partition and sequences
 - update_first_row(), to be able to do efficient sequence implementations.
 - Made binlog_log_row() global to be able to call it from ha_sequence.cc
- Added handler variable: row_already_logged, to be able to flag that the
  changed row is already logging to replication log.
- Added CF_DB_CHANGE and CF_SCHEMA_CHANGE flags to simplify
  deny_updates_if_read_only_option()
- Added sp_add_cfetch() to avoid new conflicts in sql_yacc.yy
- Moved code for add_table_options() out from sql_show.cc::show_create_table()
- Added String::append_longlong() and used it in sql_show.cc to simplify code.
- Added extra option to dd_frm_type() and ha_table_exists to indicate if
  the table is a sequence. Needed by DROP SQUENCE to not drop a table.

1 files changed, 133 insertions, 0 deletions

diff --git a/sql/sql_sequence.h b/sql/sql_sequence.h
new file mode 100644
index 00000000000..f5534d55d9b
--- /dev/null
+++ b/sql/sql_sequence.h
@@ -0,0 +1,133 @@
+/* Copyright (c) 2017, MariaDB corporation
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#ifndef SQL_SEQUENCE_INCLUDED
+#define SQL_SEQUENCE_INCLUDED
+
+#define seq_field_used_min_value 1
+#define seq_field_used_max_value 2
+#define seq_field_used_start     4
+
+/**
+   sequence_definition is used when defining a sequence as part of create
+*/
+
+class sequence_definition :public Sql_alloc
+{
+public:
+  sequence_definition():
+    min_value(1), max_value(LONGLONG_MAX-1), start(1), increment(1),
+    cache(1000), round(0), cycle(0), used_fields(0)
+  {}
+  longlong reserved_until;
+  longlong min_value;
+  longlong max_value;
+  longlong start;
+  longlong increment;
+  longlong cache;
+  ulonglong round;
+  bool     cycle;
+  uint used_fields;              // Which fields where used in CREATE
+
+  bool check_and_adjust();
+  void store_fields(TABLE *table);
+  void read_fields(TABLE *table);
+  void print_dbug()
+  {
+    DBUG_PRINT("sequence", ("reserved: %lld  start: %lld  increment: %lld  min_value: %lld  max_value: %lld  cache: %lld  round: %lld",
+                      reserved_until, start, increment, min_value,
+                        max_value, cache, round));
+  }
+};
+
+/**
+  SEQUENCE is in charge of managing the sequence values.
+  It's also responsible to generate new values and updating the sequence
+  table (engine=SQL_SEQUENCE) trough it's specialized handler interface.
+
+  If increment is 0 then the sequence will be be using
+  auto_increment_increment and auto_increment_offset variables, just like
+  AUTO_INCREMENT is using.
+*/
+
+class SEQUENCE :public sequence_definition
+{
+public:
+  SEQUENCE();
+  ~SEQUENCE();
+  int  read_initial_values(TABLE *table);
+  int  read_stored_values();
+  void lock()
+  {
+    mysql_mutex_lock(&mutex);
+  }
+  void unlock()
+  {
+    mysql_mutex_unlock(&mutex);
+  }
+  /* This must be called after sequence data has been updated */
+  void adjust_values();
+  void copy(sequence_definition *seq)
+  {
+    sequence_definition::operator= (*seq);
+    adjust_values();
+  }
+  longlong next_value(TABLE *table, bool second_round, int *error);
+
+  bool initialized;                         // If row has been read
+  bool all_values_used;
+private:
+  TABLE         *table;
+  mysql_mutex_t mutex;
+  longlong next_free_value;
+  /*
+    The following values are the values from sequence_definition
+    merged with global auto_increment_offset and auto_increment_increment
+  */
+  longlong real_increment;
+  longlong offset;
+};
+
+
+/**
+  Class to cache last value of NEXT VALUE from the sequence
+*/
+
+class SEQUENCE_LAST_VALUE
+{
+public:
+  SEQUENCE_LAST_VALUE(uchar *key_arg, uint length_arg)
+    :key(key_arg), length(length_arg)
+  {}
+  ~SEQUENCE_LAST_VALUE()
+  { my_free((void*) key); }
+  /* Returns 1 if table hasn't been dropped or re-created */
+  bool check_version(TABLE *table);
+  void set_version(TABLE *table);
+
+  const uchar *key;
+  uint length;
+  bool null_value;
+  longlong value;
+  uchar table_version[MY_UUID_SIZE];
+};
+
+
+class Create_field;
+extern bool prepare_sequence_fields(THD *thd, List<Create_field> *fields);
+extern bool check_sequence_fields(LEX *lex, List<Create_field> *fields);
+extern bool sequence_insert(THD *thd, LEX *lex, TABLE_LIST *table_list);
+#endif /* SQL_SEQUENCE_INCLUDED */