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, 22 insertions, 11 deletions

diff --git a/sql/datadict.cc b/sql/datadict.cc
index 103a33214ae..1093f2cdd09 100644
--- a/sql/datadict.cc
+++ b/sql/datadict.cc
@@ -18,6 +18,7 @@
 #include "sql_priv.h"
 #include "sql_class.h"
 #include "sql_table.h"
+#include "ha_sequence.h"
 
 static int read_string(File file, uchar**to, size_t length)
 {
@@ -46,33 +47,40 @@ static int read_string(File file, uchar**to, size_t length)
   engine_name is a LEX_STRING, where engine_name->str must point to
   a buffer of at least NAME_CHAR_LEN+1 bytes.
 
-  @retval  FRMTYPE_ERROR        error
-  @retval  FRMTYPE_TABLE        table
-  @retval  FRMTYPE_VIEW         view
+  @param[out] is_sequence  1 if table is a SEQUENCE, 0 otherwise
+
+  @retval  TABLE_TYPE_UNKNOWN   error
+  @retval  TABLE_TYPE_TABLE     table
+  @retval  TABLE_TYPE_SEQUENCE  sequence table
+  @retval  TABLE_TYPE_VIEW      view
 */
 
-frm_type_enum dd_frm_type(THD *thd, char *path, LEX_STRING *engine_name)
+Table_type dd_frm_type(THD *thd, char *path, LEX_STRING *engine_name,
+                       bool *is_sequence)
 {
   File file;
-  uchar header[10];     //"TYPE=VIEW\n" it is 10 characters
+  uchar header[40];     //"TYPE=VIEW\n" it is 10 characters
   size_t error;
-  frm_type_enum type= FRMTYPE_ERROR;
+  Table_type type= TABLE_TYPE_UNKNOWN;
   uchar dbt;
   DBUG_ENTER("dd_frm_type");
 
-  if ((file= mysql_file_open(key_file_frm, path, O_RDONLY | O_SHARE, MYF(0))) < 0)
-    DBUG_RETURN(FRMTYPE_ERROR);
+  *is_sequence= 0;
+
+  if ((file= mysql_file_open(key_file_frm, path, O_RDONLY | O_SHARE, MYF(0)))
+      < 0)
+    DBUG_RETURN(TABLE_TYPE_UNKNOWN);
   error= mysql_file_read(file, (uchar*) header, sizeof(header), MYF(MY_NABP));
 
   if (error)
     goto err;
-  if (!strncmp((char*) header, "TYPE=VIEW\n", sizeof(header)))
+  if (!strncmp((char*) header, "TYPE=VIEW\n", 10))
   {
-    type= FRMTYPE_VIEW;
+    type= TABLE_TYPE_VIEW;
     goto err;
   }
 
-  type= FRMTYPE_TABLE;
+  type= TABLE_TYPE_NORMAL;
 
   if (!is_binary_frm_header(header) || !engine_name)
     goto err;
@@ -91,6 +99,9 @@ frm_type_enum dd_frm_type(THD *thd, char *path, LEX_STRING *engine_name)
     }
   }
 
+  if (((header[39] >> 4) & 3) == HA_CHOICE_YES)
+    *is_sequence= 1;
+
   /* read the true engine name */
   {
     MY_STAT state;