Adding upstream version 1:10.5.12.upstream/1%10.5.12upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 993 insertions, 0 deletions

diff --git a/sql/sql_sequence.cc b/sql/sql_sequence.cc
new file mode 100644
index 00000000..307a0b29
--- /dev/null
+++ b/sql/sql_sequence.cc
@@ -0,0 +1,993 @@
+/*
+   Copyright (c) 2017, MariaDB Corporation, Alibaba Corporation
+   Copyrgiht (c) 2020, 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
+*/
+
+#include "mariadb.h"
+#include "sql_class.h"
+#include "sql_list.h"
+#include "sql_sequence.h"
+#include "ha_sequence.h"
+#include "sql_base.h"
+#include "sql_table.h"                          // write_bin_log
+#include "transaction.h"
+#include "lock.h"
+#include "sql_acl.h"
+
+struct Field_definition
+{
+  const char *field_name;
+  uint length;
+  const Type_handler *type_handler;
+  LEX_CSTRING comment;
+  ulong flags;
+};
+
+/*
+  Structure for all SEQUENCE tables
+
+  Note that the first field is named "next_val" to all us to have
+  NEXTVAL a reserved word that will on access be changed to
+  NEXTVAL(sequence_table). For this to work, the table can't have
+  a column named NEXTVAL.
+*/
+
+#define FL (NOT_NULL_FLAG | NO_DEFAULT_VALUE_FLAG)
+
+static Field_definition sequence_structure[]=
+{
+  {"next_not_cached_value", 21, &type_handler_slonglong,
+   {STRING_WITH_LEN("")}, FL},
+  {"minimum_value", 21, &type_handler_slonglong, {STRING_WITH_LEN("")}, FL},
+  {"maximum_value", 21, &type_handler_slonglong, {STRING_WITH_LEN("")}, FL},
+  {"start_value", 21, &type_handler_slonglong, {STRING_WITH_LEN("start value when sequences is created or value if RESTART is used")},  FL},
+  {"increment", 21, &type_handler_slonglong,
+   {STRING_WITH_LEN("increment value")}, FL},
+  {"cache_size", 21, &type_handler_ulonglong, {STRING_WITH_LEN("")},
+   FL | UNSIGNED_FLAG},
+  {"cycle_option", 1, &type_handler_utiny, {STRING_WITH_LEN("0 if no cycles are allowed, 1 if the sequence should begin a new cycle when maximum_value is passed")},
+   FL | UNSIGNED_FLAG },
+  {"cycle_count", 21, &type_handler_slonglong,
+   {STRING_WITH_LEN("How many cycles have been done")}, FL},
+  {NULL, 0, &type_handler_slonglong, {STRING_WITH_LEN("")}, 0}
+};
+
+#undef FL
+
+
+#define MAX_AUTO_INCREMENT_VALUE 65535
+
+/*
+  Check whether sequence values are valid.
+  Sets default values for fields that are not used, according to Oracle spec.
+
+  RETURN VALUES
+     false      valid
+     true       invalid
+*/
+
+bool sequence_definition::check_and_adjust(bool set_reserved_until)
+{
+  longlong max_increment;
+  DBUG_ENTER("sequence_definition::check");
+
+  if (!(real_increment= increment))
+    real_increment= global_system_variables.auto_increment_increment;
+
+  /*
+    If min_value is not set, set it to LONGLONG_MIN or 1, depending on
+    real_increment
+  */
+  if (!(used_fields & seq_field_used_min_value))
+    min_value= real_increment < 0 ? LONGLONG_MIN+1 : 1;
+
+  /*
+    If max_value is not set, set it to LONGLONG_MAX or -1, depending on
+    real_increment
+  */
+  if (!(used_fields & seq_field_used_max_value))
+    max_value= real_increment < 0 ? -1 : LONGLONG_MAX-1;
+
+  if (!(used_fields & seq_field_used_start))
+  {
+    /* Use min_value or max_value for start depending on real_increment */
+    start= real_increment < 0 ? max_value : min_value;
+  }
+
+  if (set_reserved_until)
+    reserved_until= start;
+
+  adjust_values(reserved_until);
+
+  /* To ensure that cache * real_increment will never overflow */
+  max_increment= (real_increment ?
+                  llabs(real_increment) :
+                  MAX_AUTO_INCREMENT_VALUE);
+
+  if (max_value >= start &&
+      max_value > min_value &&
+      start >= min_value &&
+      max_value != LONGLONG_MAX &&
+      min_value != LONGLONG_MIN &&
+      cache < (LONGLONG_MAX - max_increment) / max_increment &&
+      ((real_increment > 0 && reserved_until >= min_value) ||
+       (real_increment < 0 && reserved_until <= max_value)))
+    DBUG_RETURN(FALSE);
+
+  DBUG_RETURN(TRUE);                           // Error
+}
+
+
+/*
+  Read sequence values from a table
+*/
+
+void sequence_definition::read_fields(TABLE *table)
+{
+  MY_BITMAP *old_map= dbug_tmp_use_all_columns(table, &table->read_set);
+  reserved_until= table->field[0]->val_int();
+  min_value=      table->field[1]->val_int();
+  max_value=      table->field[2]->val_int();
+  start=          table->field[3]->val_int();
+  increment=      table->field[4]->val_int();
+  cache=          table->field[5]->val_int();
+  cycle=          table->field[6]->val_int();
+  round=          table->field[7]->val_int();
+  dbug_tmp_restore_column_map(&table->read_set, old_map);
+  used_fields= ~(uint) 0;
+  print_dbug();
+}
+
+
+/*
+  Store sequence into a table row
+*/
+
+void sequence_definition::store_fields(TABLE *table)
+{
+  MY_BITMAP *old_map= dbug_tmp_use_all_columns(table, &table->write_set);
+
+  /* zero possible delete markers & null bits */
+  memcpy(table->record[0], table->s->default_values, table->s->null_bytes);
+  table->field[0]->store(reserved_until, 0);
+  table->field[1]->store(min_value, 0);
+  table->field[2]->store(max_value, 0);
+  table->field[3]->store(start, 0);
+  table->field[4]->store(increment, 0);
+  table->field[5]->store(cache, 0);
+  table->field[6]->store((longlong) cycle != 0, 0);
+  table->field[7]->store((longlong) round, 1);
+
+  dbug_tmp_restore_column_map(&table->write_set, old_map);
+  print_dbug();
+}
+
+
+/*
+  Check the sequence fields through seq_fields when creating a sequence.
+
+  RETURN VALUES
+    false       Success
+    true        Failure
+*/
+
+bool check_sequence_fields(LEX *lex, List<Create_field> *fields)
+{
+  Create_field *field;
+  List_iterator_fast<Create_field> it(*fields);
+  uint field_count;
+  uint field_no;
+  const char *reason;
+  DBUG_ENTER("check_sequence_fields");
+
+  field_count= fields->elements;
+  if (field_count != array_elements(sequence_structure)-1)
+  {
+    reason= "Wrong number of columns";
+    goto err;
+  }
+  if (lex->alter_info.key_list.elements > 0)
+  {
+    reason= "Sequence tables cannot have any keys";
+    goto err;
+  }
+  if (lex->alter_info.check_constraint_list.elements > 0)
+  {
+    reason= "Sequence tables cannot have any constraints";
+    goto err;
+  }
+  if (lex->alter_info.flags & ALTER_ORDER)
+  {
+    reason= "ORDER BY";
+    goto err;
+  }
+
+  for (field_no= 0; (field= it++); field_no++)
+  {
+    Field_definition *field_def= &sequence_structure[field_no];
+    if (my_strcasecmp(system_charset_info, field_def->field_name,
+                      field->field_name.str) ||
+        field->flags != field_def->flags ||
+        field->type_handler() != field_def->type_handler ||
+        field->check_constraint || field->vcol_info)
+    {
+      reason= field->field_name.str;
+      goto err;
+    }
+  }
+  DBUG_RETURN(FALSE);
+
+err:
+  my_error(ER_SEQUENCE_INVALID_TABLE_STRUCTURE, MYF(0),
+           lex->first_select_lex()->table_list.first->db.str,
+           lex->first_select_lex()->table_list.first->table_name.str, reason);
+  DBUG_RETURN(TRUE);
+}
+
+
+/*
+  Create the fields for a SEQUENCE TABLE
+
+  RETURN VALUES
+    false       Success
+    true        Failure (out of memory)
+*/
+
+bool prepare_sequence_fields(THD *thd, List<Create_field> *fields)
+{
+  Field_definition *field_info;
+  DBUG_ENTER("prepare_sequence_fields");
+
+  for (field_info= sequence_structure; field_info->field_name ; field_info++)
+  {
+    Create_field *new_field;
+    LEX_CSTRING field_name= {field_info->field_name,
+                             strlen(field_info->field_name)};
+
+    if (unlikely(!(new_field= new Create_field())))
+      DBUG_RETURN(TRUE); /* purify inspected */
+
+    new_field->field_name=  field_name;
+    new_field->set_handler(field_info->type_handler);
+    new_field->length=      field_info->length;
+    new_field->char_length= field_info->length;
+    new_field->comment=     field_info->comment;
+    new_field->flags=       field_info->flags;
+    if (unlikely(fields->push_back(new_field)))
+      DBUG_RETURN(TRUE); /* purify inspected */
+  }
+  DBUG_RETURN(FALSE);
+}
+
+/*
+  Initialize the sequence table record as part of CREATE SEQUENCE
+
+  Store one row with sequence information.
+
+  RETURN VALUES
+    false       Success
+    true        Failure. Error reported.
+
+  NOTES
+    This function is called as part of CREATE SEQUENCE. When called
+    there are now active transactions and no open tables.
+    There is also a MDL lock on the table.
+*/
+
+bool sequence_insert(THD *thd, LEX *lex, TABLE_LIST *org_table_list)
+{
+  int error;
+  TABLE *table;
+  Reprepare_observer *save_reprepare_observer;
+  sequence_definition *seq= lex->create_info.seq_create_info;
+  bool temporary_table= org_table_list->table != 0;
+  Open_tables_backup open_tables_backup;
+  Query_tables_list query_tables_list_backup;
+  TABLE_LIST table_list;                        // For sequence table
+  DBUG_ENTER("sequence_insert");
+
+  /*
+    seq is 0 if sequence was created with CREATE TABLE instead of
+    CREATE SEQUENCE
+  */
+  if (!seq)
+  {
+    if (!(seq= new (thd->mem_root) sequence_definition))
+      DBUG_RETURN(TRUE);
+  }
+
+  /* If not temporary table */
+  if (!temporary_table)
+  {
+    /*
+      The following code works like open_system_tables_for_read()
+      The idea is:
+      - Copy the table_list object for the sequence that was created
+      - Backup the current state of open tables and create a new
+        environment for open tables without any tables opened
+     - open the newly sequence table for write
+     This is safe as the sequence table has a mdl lock thanks to the
+     create sequence statement that is calling this function
+    */
+
+    table_list.init_one_table(&org_table_list->db,
+                              &org_table_list->table_name, 
+                              NULL, TL_WRITE_DEFAULT);
+    table_list.updating=  1;
+    table_list.open_strategy= TABLE_LIST::OPEN_IF_EXISTS;
+    table_list.open_type= OT_BASE_ONLY;
+
+    DBUG_ASSERT(!thd->locked_tables_mode ||
+                (thd->variables.option_bits & OPTION_TABLE_LOCK));
+    lex->reset_n_backup_query_tables_list(&query_tables_list_backup);
+    thd->reset_n_backup_open_tables_state(&open_tables_backup);
+
+    /*
+      The FOR CREATE flag is needed to ensure that ha_open() doesn't try to
+      read the not yet existing row in the sequence table
+    */
+    thd->open_options|= HA_OPEN_FOR_CREATE;
+    /*
+      We have to reset the reprepare observer to be able to open the
+      table under prepared statements.
+    */
+    save_reprepare_observer= thd->m_reprepare_observer;
+    thd->m_reprepare_observer= 0;
+    lex->sql_command= SQLCOM_CREATE_SEQUENCE;
+    error= open_and_lock_tables(thd, &table_list, FALSE,
+                                MYSQL_LOCK_IGNORE_TIMEOUT |
+                                MYSQL_OPEN_HAS_MDL_LOCK);
+    thd->open_options&= ~HA_OPEN_FOR_CREATE;
+    thd->m_reprepare_observer= save_reprepare_observer;
+    if (unlikely(error))
+    {
+      lex->restore_backup_query_tables_list(&query_tables_list_backup);
+      thd->restore_backup_open_tables_state(&open_tables_backup);
+      DBUG_RETURN(error);
+    }
+    table= table_list.table;
+  }
+  else
+    table= org_table_list->table;
+
+  seq->reserved_until= seq->start;
+  error= seq->write_initial_sequence(table);
+
+  if (trans_commit_stmt(thd))
+    error= 1;
+  if (trans_commit_implicit(thd))
+    error= 1;
+
+  if (!temporary_table)
+  {
+    close_thread_tables(thd);
+    lex->restore_backup_query_tables_list(&query_tables_list_backup);
+    thd->restore_backup_open_tables_state(&open_tables_backup);
+
+    /* OPTION_TABLE_LOCK was reset in trans_commit_implicit */
+    if (thd->locked_tables_mode)
+      thd->variables.option_bits|= OPTION_TABLE_LOCK;
+  }
+  DBUG_RETURN(error);
+}
+
+
+/* Create a SQUENCE object */
+
+SEQUENCE::SEQUENCE() :all_values_used(0), initialized(SEQ_UNINTIALIZED)
+{
+  mysql_rwlock_init(key_LOCK_SEQUENCE, &mutex);
+}
+
+SEQUENCE::~SEQUENCE()
+{
+  mysql_rwlock_destroy(&mutex);
+}
+
+/*
+  The following functions is to ensure that we when reserve new values
+  trough sequence object sequence we have only one writer at at time.
+  A sequence table can have many readers (trough normal SELECT's).
+
+  We mark that we have a write lock in the table object so that
+  ha_sequence::ha_write() can check if we have a lock. If already locked, then
+  ha_write() knows that we are running a sequence operation. If not, then
+  ha_write() knows that it's an INSERT.
+*/
+
+void SEQUENCE::write_lock(TABLE *table)
+{
+  DBUG_ASSERT(((ha_sequence*) table->file)->is_locked() == 0);
+  mysql_rwlock_wrlock(&mutex);
+  ((ha_sequence*) table->file)->write_lock();
+}
+void SEQUENCE::write_unlock(TABLE *table)
+{
+  ((ha_sequence*) table->file)->unlock();
+  mysql_rwlock_unlock(&mutex);
+}
+void SEQUENCE::read_lock(TABLE *table)
+{
+  if (!((ha_sequence*) table->file)->is_locked())
+    mysql_rwlock_rdlock(&mutex);
+}
+void SEQUENCE::read_unlock(TABLE *table)
+{
+  if (!((ha_sequence*) table->file)->is_locked())
+    mysql_rwlock_unlock(&mutex);
+}
+
+/**
+   Read values from the sequence tables to table_share->sequence.
+   This is called from ha_open() when the table is not yet locked
+*/
+
+int SEQUENCE::read_initial_values(TABLE *table)
+{
+  int error= 0;
+  enum thr_lock_type save_lock_type;
+  MDL_request mdl_request;                      // Empty constructor!
+  DBUG_ENTER("SEQUENCE::read_initial_values");
+
+  if (likely(initialized != SEQ_UNINTIALIZED))
+    DBUG_RETURN(0);
+  write_lock(table);
+  if (likely(initialized == SEQ_UNINTIALIZED))
+  {
+    MYSQL_LOCK *lock;
+    bool mdl_lock_used= 0;
+    THD *thd= table->in_use;
+    bool has_active_transaction= !thd->transaction->stmt.is_empty();
+    /*
+      There is already a mdl_ticket for this table. However, for list_fields
+      the MDL lock is of type MDL_SHARED_HIGH_PRIO which is not usable
+      for doing a table lock. Get a proper read lock to solve this.
+    */
+    if (table->mdl_ticket == 0)
+    {
+      MDL_request_list mdl_requests;
+      mdl_lock_used= 1;
+      /*
+        This happens if first request is SHOW CREATE TABLE or LIST FIELDS
+        where we don't have a mdl lock on the table
+      */
+
+      MDL_REQUEST_INIT(&mdl_request, MDL_key::TABLE, table->s->db.str,
+                       table->s->table_name.str, MDL_SHARED_READ,
+                       MDL_EXPLICIT);
+      mdl_requests.push_front(&mdl_request);
+      if (thd->mdl_context.acquire_locks(&mdl_requests,
+                                         thd->variables.lock_wait_timeout))
+      {
+        write_unlock(table);
+        DBUG_RETURN(HA_ERR_LOCK_WAIT_TIMEOUT);
+      }
+    }
+    save_lock_type= table->reginfo.lock_type;
+    table->reginfo.lock_type= TL_READ;
+    if (!(lock= mysql_lock_tables(thd, &table, 1,
+                                  MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY)))
+    {
+      if (mdl_lock_used)
+        thd->mdl_context.release_lock(mdl_request.ticket);
+      write_unlock(table);
+
+      if (!has_active_transaction && !thd->transaction->stmt.is_empty() &&
+          !thd->in_sub_stmt)
+        trans_commit_stmt(thd);
+      DBUG_RETURN(HA_ERR_LOCK_WAIT_TIMEOUT);
+    }
+    DBUG_ASSERT(table->reginfo.lock_type == TL_READ);
+    if (likely(!(error= read_stored_values(table))))
+      initialized= SEQ_READY_TO_USE;
+    mysql_unlock_tables(thd, lock);
+    if (mdl_lock_used)
+      thd->mdl_context.release_lock(mdl_request.ticket);
+
+    /* Reset value to default */
+    table->reginfo.lock_type= save_lock_type;
+    /*
+      Doing mysql_lock_tables() may have started a read only transaction.
+      If that happend, it's better that we commit it now, as a lot of
+      code assumes that there is no active stmt transaction directly after
+      open_tables().
+      But we also don't want to commit the stmt transaction while in a
+      substatement, see MDEV-15977.
+    */
+    if (!has_active_transaction && !thd->transaction->stmt.is_empty() &&
+        !thd->in_sub_stmt)
+      trans_commit_stmt(thd);
+  }
+  write_unlock(table);
+  DBUG_RETURN(error);
+}
+
+
+/*
+  Do the actiual reading of data from sequence table and
+  update values in the sequence object.
+
+  Called once from when table is opened
+*/
+
+int SEQUENCE::read_stored_values(TABLE *table)
+{
+  int error;
+  DBUG_ENTER("SEQUENCE::read_stored_values");
+
+  MY_BITMAP *save_read_set= tmp_use_all_columns(table, &table->read_set);
+  error= table->file->ha_read_first_row(table->record[0], MAX_KEY);
+  tmp_restore_column_map(&table->read_set, save_read_set);
+
+  if (unlikely(error))
+  {
+    table->file->print_error(error, MYF(0));
+    DBUG_RETURN(error);
+  }
+  read_fields(table);
+  adjust_values(reserved_until);
+
+  all_values_used= 0;
+  DBUG_RETURN(0);
+}
+
+
+/*
+  Adjust values after reading a the stored state
+*/
+
+void sequence_definition::adjust_values(longlong next_value)
+{
+  next_free_value= next_value;
+  if (!(real_increment= increment))
+  {
+    longlong offset= 0;
+    longlong off, to_add;
+    /* Use auto_increment_increment and auto_increment_offset */
+
+    if ((real_increment= global_system_variables.auto_increment_increment)
+        != 1)
+      offset= (global_system_variables.auto_increment_offset %
+               global_system_variables.auto_increment_increment);
+
+    /*
+      Ensure that next_free_value has the right offset, so that we
+      can generate a serie by just adding real_increment.
+    */
+    off= next_free_value % real_increment;
+    if (off < 0)
+      off+= real_increment;
+    to_add= (real_increment + offset - off) % real_increment;
+
+    /*
+      Check if add will make next_free_value bigger than max_value,
+      taken into account that next_free_value or max_value addition
+      may overflow
+    */
+    if (next_free_value > max_value - to_add ||
+        next_free_value + to_add > max_value)
+      next_free_value= max_value+1;
+    else
+    {
+      next_free_value+= to_add;
+      DBUG_ASSERT(llabs(next_free_value % real_increment) == offset);
+    }
+  }
+}
+
+
+/**
+   Write initial sequence information for CREATE and ALTER to sequence table
+*/
+
+int sequence_definition::write_initial_sequence(TABLE *table)
+{
+  int error;
+  MY_BITMAP *save_write_set;
+
+  store_fields(table);
+  /* Store the sequence values in table share */
+  table->s->sequence->copy(this);
+  /*
+    Sequence values will be replicated as a statement
+    like 'create sequence'. So disable row logging for this table & statement
+  */
+  table->file->row_logging= table->file->row_logging_init= 0;
+  save_write_set= table->write_set;
+  table->write_set= &table->s->all_set;
+  table->s->sequence->initialized= SEQUENCE::SEQ_IN_PREPARE;
+  error= table->file->ha_write_row(table->record[0]);
+  table->s->sequence->initialized= SEQUENCE::SEQ_UNINTIALIZED;
+  table->write_set= save_write_set;
+  if (unlikely(error))
+    table->file->print_error(error, MYF(0));
+  else
+  {
+    /*
+      Sequence structure is up to date and table has one row,
+      sequence is now usable
+    */
+    table->s->sequence->initialized= SEQUENCE::SEQ_READY_TO_USE;
+  }
+  return error;
+}
+
+
+/**
+   Store current sequence values into the sequence table
+*/
+
+int sequence_definition::write(TABLE *table, bool all_fields)
+{
+  int error;
+  MY_BITMAP *save_rpl_write_set, *save_write_set, *save_read_set;
+  DBUG_ASSERT(((ha_sequence*) table->file)->is_locked());
+
+  save_rpl_write_set= table->rpl_write_set;
+  if (likely(!all_fields))
+  {
+    /* Only write next_value and round to binary log */
+    table->rpl_write_set= &table->def_rpl_write_set;
+    bitmap_clear_all(table->rpl_write_set);
+    bitmap_set_bit(table->rpl_write_set, NEXT_FIELD_NO);
+    bitmap_set_bit(table->rpl_write_set, ROUND_FIELD_NO);
+  }
+  else
+    table->rpl_write_set= &table->s->all_set;
+
+  /* Update table */
+  save_write_set= table->write_set;
+  save_read_set=  table->read_set;
+  table->read_set= table->write_set= &table->s->all_set;
+  table->file->column_bitmaps_signal();
+  store_fields(table);
+  if (unlikely((error= table->file->ha_write_row(table->record[0]))))
+    table->file->print_error(error, MYF(0));
+  table->rpl_write_set= save_rpl_write_set;
+  table->read_set=  save_read_set;
+  table->write_set= save_write_set;
+  table->file->column_bitmaps_signal();
+  return error;
+}
+
+
+/**
+   Get next value for sequence
+
+   @param in   table  Sequence table
+   @param in   second_round
+                      1 if recursive call (out of values once)
+   @param out  error  Set this to <> 0 in case of error
+                      push_warning_printf(WARN_LEVEL_WARN) has been called
+
+
+   @retval     0      Next number or error. Check error variable
+               #      Next sequence number
+
+   NOTES:
+     Return next_free_value and increment next_free_value to next allowed
+     value or reserved_value if out of range
+     if next_free_value >= reserved_value reserve a new range by writing
+     a record to the sequence table.
+
+  The state of the variables:
+    next_free_value contains next value to use. It may be
+    bigger than max_value or less than min_value if end of sequence.
+    reserved_until contains the last value written to the file. All
+    values up to this one can be used.
+    If next_free_value >= reserved_until we have to reserve new
+    values from the sequence.
+*/
+
+longlong SEQUENCE::next_value(TABLE *table, bool second_round, int *error)
+{
+  longlong res_value, org_reserved_until, add_to;
+  bool out_of_values;
+  DBUG_ENTER("SEQUENCE::next_value");
+
+  *error= 0;
+  if (!second_round)
+    write_lock(table);
+
+  res_value= next_free_value;
+  next_free_value= increment_value(next_free_value);
+
+  if ((real_increment > 0 && res_value < reserved_until) ||
+      (real_increment < 0 && res_value > reserved_until))
+  {
+    write_unlock(table);
+    DBUG_RETURN(res_value);
+  }
+
+  if (all_values_used)
+    goto err;
+
+  org_reserved_until= reserved_until;
+
+  /*
+    Out of cached values, reserve 'cache' new ones
+    The cache value is checked on insert so the following can't
+    overflow
+  */
+  add_to= cache ? real_increment * cache : real_increment;
+  out_of_values= 0;
+
+  if (real_increment > 0)
+  {
+    if (reserved_until > max_value - add_to ||
+        reserved_until + add_to > max_value)
+    {
+      reserved_until= max_value + 1;
+      out_of_values= res_value >= reserved_until;
+    }
+    else
+      reserved_until+= add_to;
+  }
+  else
+  {
+    if (reserved_until + add_to < min_value ||
+        reserved_until < min_value - add_to)
+    {
+      reserved_until= min_value - 1;
+      out_of_values= res_value <= reserved_until;
+    }
+    else
+      reserved_until+= add_to;
+  }
+  if (out_of_values)
+  {
+    if (!cycle || second_round)
+      goto err;
+    round++;
+    reserved_until= real_increment >0 ? min_value : max_value;
+    adjust_values(reserved_until);              // Fix next_free_value
+    /*
+      We have to do everything again to ensure that the given range was
+      not empty, which could happen if increment == 0
+    */
+    DBUG_RETURN(next_value(table, 1, error));
+  }
+
+  if (unlikely((*error= write(table, 0))))
+  {
+    reserved_until= org_reserved_until;
+    next_free_value= res_value;
+  }
+
+  write_unlock(table);
+  DBUG_RETURN(res_value);
+
+err:
+  write_unlock(table);
+  my_error(ER_SEQUENCE_RUN_OUT, MYF(0), table->s->db.str,
+           table->s->table_name.str);
+  *error= ER_SEQUENCE_RUN_OUT;
+  all_values_used= 1;
+  DBUG_RETURN(0);
+}
+
+
+/*
+   The following functions is to detect if a table has been dropped
+   and re-created since last call to PREVIOUS VALUE.
+
+   This is needed as we don't delete dropped sequences from THD->sequence
+   for DROP TABLE.
+*/
+
+bool SEQUENCE_LAST_VALUE::check_version(TABLE *table)
+{
+  DBUG_ASSERT(table->s->tabledef_version.length == MY_UUID_SIZE);
+  return memcmp(table->s->tabledef_version.str, table_version,
+                MY_UUID_SIZE) != 0;
+}
+
+void SEQUENCE_LAST_VALUE::set_version(TABLE *table)
+{
+  memcpy(table_version, table->s->tabledef_version.str, MY_UUID_SIZE);
+}
+
+/**
+   Set the next value for sequence
+
+   @param in   table       Sequence table
+   @param in   next_val    Next free value
+   @param in   next_round  Round for 'next_value' (in case of cycles)
+   @param in   is_used     1 if next_val is already used
+
+   @retval     0      ok, value adjusted
+               -1     value was less than current value
+               1      error when storing value
+
+   @comment
+   A new value is set only if "nextval,next_round" is less than
+   "next_free_value,round". This is needed as in replication
+   setvalue() calls may come out to the slave out-of-order.
+   Storing only the highest value ensures that sequence object will always
+   contain the highest used value when the slave is promoted to a master.
+*/
+
+int SEQUENCE::set_value(TABLE *table, longlong next_val, ulonglong next_round,
+                         bool is_used)
+{
+  int error= -1;
+  bool needs_to_be_stored= 0;
+  longlong org_reserved_until=  reserved_until;
+  longlong org_next_free_value= next_free_value;
+  ulonglong org_round= round;
+  DBUG_ENTER("SEQUENCE::set_value");
+
+  write_lock(table);
+  if (is_used)
+    next_val= increment_value(next_val);
+
+  if (round > next_round)
+    goto end;                                   // error = -1
+  if (round == next_round)
+  {
+    if (real_increment > 0  ?
+        next_val < next_free_value :
+        next_val > next_free_value)
+      goto end;                                 // error = -1
+    if (next_val == next_free_value)
+    {
+      error= 0;
+      goto end;
+    }
+  }
+  else if (cycle == 0)
+  {
+    // round < next_round && no cycles, which is impossible
+    my_error(ER_SEQUENCE_RUN_OUT, MYF(0), table->s->db.str,
+             table->s->table_name.str);
+    error= 1;
+    goto end;
+  }
+  else
+    needs_to_be_stored= 1;
+
+  round= next_round;
+  adjust_values(next_val);
+  if ((real_increment > 0 ?
+       next_free_value > reserved_until :
+       next_free_value < reserved_until) ||
+      needs_to_be_stored)
+  {
+    reserved_until= next_free_value;
+    if (write(table, 0))
+    {
+      reserved_until=  org_reserved_until;
+      next_free_value= org_next_free_value;
+      round= org_round;
+      error= 1;
+      goto end;
+    }
+  }
+  error= 0;
+
+end:
+  write_unlock(table);
+  DBUG_RETURN(error);
+}
+
+
+bool Sql_cmd_alter_sequence::execute(THD *thd)
+{
+  int error= 0;
+  int trapped_errors= 0;
+  LEX *lex= thd->lex;
+  TABLE_LIST *first_table= lex->query_tables;
+  TABLE *table;
+  sequence_definition *new_seq= lex->create_info.seq_create_info;
+  SEQUENCE *seq;
+  No_such_table_error_handler no_such_table_handler;
+  DBUG_ENTER("Sql_cmd_alter_sequence::execute");
+
+  if (check_access(thd, ALTER_ACL, first_table->db.str,
+                   &first_table->grant.privilege,
+                   &first_table->grant.m_internal,
+                   0, 0))
+    DBUG_RETURN(TRUE);                  /* purecov: inspected */
+
+  if (check_grant(thd, ALTER_ACL, first_table, FALSE, 1, FALSE))
+    DBUG_RETURN(TRUE);                  /* purecov: inspected */
+
+  if (if_exists())
+    thd->push_internal_handler(&no_such_table_handler);
+  error= open_and_lock_tables(thd, first_table, FALSE, 0);
+  if (if_exists())
+  {
+    trapped_errors= no_such_table_handler.safely_trapped_errors();
+    thd->pop_internal_handler();
+  }
+  if (unlikely(error))
+  {
+    if (trapped_errors)
+    {
+      StringBuffer<FN_REFLEN> tbl_name;
+      tbl_name.append(&first_table->db);
+      tbl_name.append('.');
+      tbl_name.append(&first_table->table_name);
+      push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
+                          ER_UNKNOWN_SEQUENCES,
+                          ER_THD(thd, ER_UNKNOWN_SEQUENCES),
+                          tbl_name.c_ptr_safe());
+      my_ok(thd);
+      DBUG_RETURN(FALSE);
+    }
+    DBUG_RETURN(TRUE);
+  }
+
+  table= first_table->table;
+  seq= table->s->sequence;
+
+  seq->write_lock(table);
+  new_seq->reserved_until= seq->reserved_until;
+
+  /* Copy from old sequence those fields that the user didn't specified */
+  if (!(new_seq->used_fields & seq_field_used_increment))
+    new_seq->increment= seq->increment;
+  if (!(new_seq->used_fields & seq_field_used_min_value))
+    new_seq->min_value= seq->min_value;
+  if (!(new_seq->used_fields & seq_field_used_max_value))
+    new_seq->max_value= seq->max_value;
+  if (!(new_seq->used_fields & seq_field_used_start))
+    new_seq->start=          seq->start;
+  if (!(new_seq->used_fields & seq_field_used_cache))
+    new_seq->cache= seq->cache;
+  if (!(new_seq->used_fields & seq_field_used_cycle))
+    new_seq->cycle= seq->cycle;
+
+  /* If we should restart from a new value */
+  if (new_seq->used_fields & seq_field_used_restart)
+  {
+    if (!(new_seq->used_fields & seq_field_used_restart_value))
+      new_seq->restart=      new_seq->start;
+    new_seq->reserved_until= new_seq->restart;
+  }
+
+  /* Let check_and_adjust think all fields are used */
+  new_seq->used_fields= ~0;
+  if (new_seq->check_and_adjust(0))
+  {
+    my_error(ER_SEQUENCE_INVALID_DATA, MYF(0),
+             first_table->db.str,
+             first_table->table_name.str);
+    error= 1;
+    seq->write_unlock(table);
+    goto end;
+  }
+
+  if (likely(!(error= new_seq->write(table, 1))))
+  {
+    /* Store the sequence values in table share */
+    seq->copy(new_seq);
+  }
+  else
+    table->file->print_error(error, MYF(0));
+  seq->write_unlock(table);
+  if (trans_commit_stmt(thd))
+    error= 1;
+  if (trans_commit_implicit(thd))
+    error= 1;
+  if (likely(!error))
+    error= write_bin_log(thd, 1, thd->query(), thd->query_length());
+  if (likely(!error))
+    my_ok(thd);
+
+end:
+  DBUG_RETURN(error);
+}