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, 547 insertions, 0 deletions

diff --git a/sql/sql_truncate.cc b/sql/sql_truncate.cc
new file mode 100644
index 00000000..e699869d
--- /dev/null
+++ b/sql/sql_truncate.cc
@@ -0,0 +1,547 @@
+/* Copyright (c) 2010, 2015, Oracle and/or its affiliates.
+   Copyright (c) 2012, 2018, MariaDB
+
+   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 02110-1335  USA */
+
+#include "mariadb.h"
+#include "debug_sync.h"  // DEBUG_SYNC
+#include "table.h"       // TABLE, FOREIGN_KEY_INFO
+#include "sql_class.h"   // THD
+#include "sql_base.h"    // open_and_lock_tables
+#include "sql_table.h"   // write_bin_log
+#include "datadict.h"    // dd_recreate_table()
+#include "lock.h"        // MYSQL_OPEN_* flags
+#include "sql_acl.h"     // DROP_ACL
+#include "sql_parse.h"   // check_one_table_access()
+#include "sql_truncate.h"
+#include "wsrep_mysqld.h"
+#include "sql_show.h"    //append_identifier()
+#include "sql_select.h"
+#include "sql_delete.h"
+
+/**
+  Append a list of field names to a string.
+
+  @param  str     The string.
+  @param  fields  The list of field names.
+
+  @return TRUE on failure, FALSE otherwise.
+*/
+
+static bool fk_info_append_fields(THD *thd, String *str,
+                                  List<LEX_CSTRING> *fields)
+{
+  bool res= FALSE;
+  LEX_CSTRING *field;
+  List_iterator_fast<LEX_CSTRING> it(*fields);
+
+  while ((field= it++))
+  {
+    res|= append_identifier(thd, str, field);
+    res|= str->append(", ");
+  }
+
+  str->chop();
+  str->chop();
+
+  return res;
+}
+
+
+/**
+  Generate a foreign key description suitable for a error message.
+
+  @param thd          Thread context.
+  @param fk_info   The foreign key information.
+
+  @return A human-readable string describing the foreign key.
+*/
+
+static const char *fk_info_str(THD *thd, FOREIGN_KEY_INFO *fk_info)
+{
+  bool res= FALSE;
+  char buffer[STRING_BUFFER_USUAL_SIZE*2];
+  String str(buffer, sizeof(buffer), system_charset_info);
+
+  str.length(0);
+
+  /*
+    `db`.`tbl`, CONSTRAINT `id` FOREIGN KEY (`fk`) REFERENCES `db`.`tbl` (`fk`)
+  */
+
+  res|= append_identifier(thd, &str, fk_info->foreign_db);
+  res|= str.append(".");
+  res|= append_identifier(thd, &str, fk_info->foreign_table);
+  res|= str.append(", CONSTRAINT ");
+  res|= append_identifier(thd, &str, fk_info->foreign_id);
+  res|= str.append(" FOREIGN KEY (");
+  res|= fk_info_append_fields(thd, &str, &fk_info->foreign_fields);
+  res|= str.append(") REFERENCES ");
+  res|= append_identifier(thd, &str, fk_info->referenced_db);
+  res|= str.append(".");
+  res|= append_identifier(thd, &str, fk_info->referenced_table);
+  res|= str.append(" (");
+  res|= fk_info_append_fields(thd, &str, &fk_info->referenced_fields);
+  res|= str.append(')');
+
+  return res ? NULL : thd->strmake(str.ptr(), str.length());
+}
+
+
+/**
+  Check and emit a fatal error if the table which is going to be
+  affected by TRUNCATE TABLE is a parent table in some non-self-
+  referencing foreign key.
+
+  @remark The intention is to allow truncate only for tables that
+          are not dependent on other tables.
+
+  @param  thd    Thread context.
+  @param  table  Table handle.
+
+  @retval FALSE  This table is not parent in a non-self-referencing foreign
+                 key. Statement can proceed.
+  @retval TRUE   This table is parent in a non-self-referencing foreign key,
+                 error was emitted.
+*/
+
+static bool
+fk_truncate_illegal_if_parent(THD *thd, TABLE *table)
+{
+  FOREIGN_KEY_INFO *fk_info;
+  List<FOREIGN_KEY_INFO> fk_list;
+  List_iterator_fast<FOREIGN_KEY_INFO> it;
+
+  /*
+    Bail out early if the table is not referenced by a foreign key.
+    In this case, the table could only be, if at all, a child table.
+  */
+  if (! table->file->referenced_by_foreign_key())
+    return FALSE;
+
+  /*
+    This table _is_ referenced by a foreign key. At this point, only
+    self-referencing keys are acceptable. For this reason, get the list
+    of foreign keys referencing this table in order to check the name
+    of the child (dependent) tables.
+  */
+  table->file->get_parent_foreign_key_list(thd, &fk_list);
+
+  /* Out of memory when building list. */
+  if (unlikely(thd->is_error()))
+    return TRUE;
+
+  it.init(fk_list);
+
+  /* Loop over the set of foreign keys for which this table is a parent. */
+  while ((fk_info= it++))
+  {
+    if (lex_string_cmp(system_charset_info, fk_info->referenced_db,
+                       &table->s->db) ||
+        lex_string_cmp(system_charset_info, fk_info->referenced_table,
+                       &table->s->table_name) ||
+        lex_string_cmp(system_charset_info, fk_info->foreign_db,
+                       &table->s->db) ||
+        lex_string_cmp(system_charset_info, fk_info->foreign_table,
+                       &table->s->table_name))
+      break;
+  }
+
+  /* Table is parent in a non-self-referencing foreign key. */
+  if (fk_info)
+  {
+    my_error(ER_TRUNCATE_ILLEGAL_FK, MYF(0), fk_info_str(thd, fk_info));
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+
+/*
+  Open and truncate a locked table.
+
+  @param  thd           Thread context.
+  @param  table_ref     Table list element for the table to be truncated.
+  @param  is_tmp_table  True if element refers to a temp table.
+
+  @retval TRUNCATE_OK   Truncate was successful and statement can be safely
+                        binlogged.
+  @retval TRUNCATE_FAILED_BUT_BINLOG Truncate failed but still go ahead with
+                        binlogging as in case of non transactional tables
+                        partial truncation is possible.
+
+  @retval TRUNCATE_FAILED_SKIP_BINLOG Truncate was not successful hence donot
+                        binlong the statement.
+*/
+
+enum Sql_cmd_truncate_table::truncate_result
+Sql_cmd_truncate_table::handler_truncate(THD *thd, TABLE_LIST *table_ref,
+                                         bool is_tmp_table)
+{
+  int error= 0;
+  uint flags= 0;
+  DBUG_ENTER("Sql_cmd_truncate_table::handler_truncate");
+
+  /*
+    Can't recreate, the engine must mechanically delete all rows
+    in the table. Use open_and_lock_tables() to open a write cursor.
+  */
+
+  /* If it is a temporary table, no need to take locks. */
+  if (!is_tmp_table)
+  {
+    /* We don't need to load triggers. */
+    DBUG_ASSERT(table_ref->trg_event_map == 0);
+    /*
+      Our metadata lock guarantees that no transaction is reading
+      or writing into the table. Yet, to open a write cursor we need
+      a thr_lock lock. Allow to open base tables only.
+    */
+    table_ref->required_type= TABLE_TYPE_NORMAL;
+    /*
+      Ignore pending FLUSH TABLES since we don't want to release
+      the MDL lock taken above and otherwise there is no way to
+      wait for FLUSH TABLES in deadlock-free fashion.
+    */
+    flags= MYSQL_OPEN_IGNORE_FLUSH;
+    /*
+      Even though we have an MDL lock on the table here, we don't
+      pass MYSQL_OPEN_HAS_MDL_LOCK to open_and_lock_tables
+      since to truncate a MERGE table, we must open and lock
+      merge children, and on those we don't have an MDL lock.
+      Thus clear the ticket to satisfy MDL asserts.
+    */
+    table_ref->mdl_request.ticket= NULL;
+  }
+
+  /* Open the table as it will handle some required preparations. */
+  if (open_and_lock_tables(thd, table_ref, FALSE, flags))
+    DBUG_RETURN(TRUNCATE_FAILED_SKIP_BINLOG);
+
+  /* Whether to truncate regardless of foreign keys. */
+  if (! (thd->variables.option_bits & OPTION_NO_FOREIGN_KEY_CHECKS))
+    if (fk_truncate_illegal_if_parent(thd, table_ref->table))
+      DBUG_RETURN(TRUNCATE_FAILED_SKIP_BINLOG);
+
+  error= table_ref->table->file->ha_truncate();
+  if (unlikely(error))
+  {
+    table_ref->table->file->print_error(error, MYF(0));
+    /*
+      If truncate method is not implemented then we don't binlog the
+      statement. If truncation has failed in a transactional engine then also
+      we don't binlog the statment. Only in non transactional engine we binlog
+      inspite of errors.
+     */
+    if (error == HA_ERR_WRONG_COMMAND ||
+        table_ref->table->file->has_transactions_and_rollback())
+      DBUG_RETURN(TRUNCATE_FAILED_SKIP_BINLOG);
+    else
+      DBUG_RETURN(TRUNCATE_FAILED_BUT_BINLOG);
+  }
+  DBUG_RETURN(TRUNCATE_OK);
+}
+
+
+/*
+  Handle locking a base table for truncate.
+
+  @param[in]  thd               Thread context.
+  @param[in]  table_ref         Table list element for the table to
+                                be truncated.
+  @param[out] hton_can_recreate Set to TRUE if table can be dropped
+                                and recreated.
+
+  @retval  FALSE  Success.
+  @retval  TRUE   Error.
+*/
+
+bool Sql_cmd_truncate_table::lock_table(THD *thd, TABLE_LIST *table_ref,
+                                        bool *hton_can_recreate)
+{
+  handlerton *hton;
+  bool versioned;
+  bool sequence= false;
+  TABLE *table= NULL;
+  DBUG_ENTER("Sql_cmd_truncate_table::lock_table");
+
+  /* Lock types are set in the parser. */
+  DBUG_ASSERT(table_ref->lock_type == TL_WRITE);
+  /* The handler truncate protocol dictates a exclusive lock. */
+  DBUG_ASSERT(table_ref->mdl_request.type == MDL_EXCLUSIVE);
+
+  /*
+    Before doing anything else, acquire a metadata lock on the table,
+    or ensure we have one.  We don't use open_and_lock_tables()
+    right away because we want to be able to truncate (and recreate)
+    corrupted tables, those that we can't fully open.
+
+    MySQL manual documents that TRUNCATE can be used to repair a
+    damaged table, i.e. a table that can not be fully "opened".
+    In particular MySQL manual says: As long as the table format
+    file tbl_name.frm is valid, the table can be re-created as
+    an empty table with TRUNCATE TABLE, even if the data or index
+    files have become corrupted.
+  */
+  if (thd->locked_tables_mode)
+  {
+    if (!(table= find_table_for_mdl_upgrade(thd, table_ref->db.str,
+                                            table_ref->table_name.str, NULL)))
+      DBUG_RETURN(TRUE);
+
+    versioned= table->versioned();
+    hton= table->file->ht;
+#ifdef WITH_WSREP
+    if (WSREP(thd) &&
+	!wsrep_should_replicate_ddl(thd, hton->db_type))
+      DBUG_RETURN(TRUE);
+#endif
+
+    table_ref->mdl_request.ticket= table->mdl_ticket;
+  }
+  else
+  {
+    DBUG_ASSERT(table_ref->next_global == NULL);
+    if (lock_table_names(thd, table_ref, NULL,
+                         thd->variables.lock_wait_timeout, 0))
+      DBUG_RETURN(TRUE);
+
+    TABLE_SHARE *share= tdc_acquire_share(thd, table_ref, GTS_TABLE | GTS_VIEW);
+    if (share == NULL)
+      DBUG_RETURN(TRUE);
+    DBUG_ASSERT(share != UNUSABLE_TABLE_SHARE);
+
+    versioned= share->versioned;
+    sequence= share->table_type == TABLE_TYPE_SEQUENCE;
+    hton= share->db_type();
+#ifdef WITH_WSREP
+    if (WSREP(thd) &&
+	hton != view_pseudo_hton &&
+	!wsrep_should_replicate_ddl(thd, hton->db_type))
+    {
+      tdc_release_share(share);
+      DBUG_RETURN(TRUE);
+    }
+#endif
+
+    if (!versioned)
+      tdc_remove_referenced_share(thd, share);
+    else
+      tdc_release_share(share);
+
+    if (hton == view_pseudo_hton)
+    {
+      my_error(ER_NO_SUCH_TABLE, MYF(0), table_ref->db.str,
+               table_ref->table_name.str);
+      DBUG_RETURN(TRUE);
+    }
+  }
+
+  *hton_can_recreate= !sequence
+                      && ha_check_storage_engine_flag(hton, HTON_CAN_RECREATE);
+
+  if (versioned)
+  {
+    my_error(ER_VERS_NOT_SUPPORTED, MYF(0), "TRUNCATE TABLE");
+    DBUG_RETURN(TRUE);
+  }
+
+  /*
+    A storage engine can recreate or truncate the table only if there
+    are no references to it from anywhere, i.e. no cached TABLE in the
+    table cache.
+  */
+  if (thd->locked_tables_mode)
+  {
+    DEBUG_SYNC(thd, "upgrade_lock_for_truncate");
+    /* To remove the table from the cache we need an exclusive lock. */
+    if (wait_while_table_is_used(thd, table,
+          *hton_can_recreate ? HA_EXTRA_PREPARE_FOR_DROP : HA_EXTRA_NOT_USED))
+      DBUG_RETURN(TRUE);
+    m_ticket_downgrade= table->mdl_ticket;
+    /* Close if table is going to be recreated. */
+    if (*hton_can_recreate)
+      close_all_tables_for_name(thd, table->s, HA_EXTRA_NOT_USED, NULL);
+  }
+  DBUG_RETURN(FALSE);
+}
+
+
+/*
+  Optimized delete of all rows by doing a full generate of the table.
+
+  @remark Will work even if the .MYI and .MYD files are destroyed.
+          In other words, it works as long as the .FRM is intact and
+          the engine supports re-create.
+
+  @param  thd         Thread context.
+  @param  table_ref   Table list element for the table to be truncated.
+
+  @retval  FALSE  Success.
+  @retval  TRUE   Error.
+*/
+
+bool Sql_cmd_truncate_table::truncate_table(THD *thd, TABLE_LIST *table_ref)
+{
+  int error;
+  bool binlog_stmt;
+  DBUG_ENTER("Sql_cmd_truncate_table::truncate_table");
+
+  DBUG_ASSERT((!table_ref->table) ||
+              (table_ref->table && table_ref->table->s));
+
+  /* Initialize, or reinitialize in case of reexecution (SP). */
+  m_ticket_downgrade= NULL;
+
+  /* If it is a temporary table, no need to take locks. */
+  if (is_temporary_table(table_ref))
+  {
+    /* In RBR, the statement is not binlogged if the table is temporary. */
+    binlog_stmt= !thd->is_current_stmt_binlog_format_row();
+
+    thd->close_unused_temporary_table_instances(table_ref);
+
+    error= handler_truncate(thd, table_ref, TRUE);
+
+    /*
+      No need to invalidate the query cache, queries with temporary
+      tables are not in the cache. No need to write to the binary
+      log a failed row-by-row delete even if under RBR as the table
+      might not exist on the slave.
+    */
+  }
+  else /* It's not a temporary table. */
+  {
+    bool hton_can_recreate;
+
+#ifdef WITH_WSREP
+    if (WSREP(thd) && wsrep_thd_is_local(thd))
+    {
+      wsrep::key_array keys;
+      /* Do not start TOI if table is not found */
+      if (!wsrep_append_fk_parent_table(thd, table_ref, &keys))
+      {
+        if (keys.empty())
+        {
+          WSREP_TO_ISOLATION_BEGIN_IF(table_ref->db.str, table_ref->table_name.str, NULL)
+          {
+            DBUG_RETURN(TRUE);
+          }
+        } else {
+          WSREP_TO_ISOLATION_BEGIN_FK_TABLES(NULL, NULL, table_ref, &keys)
+          {
+            DBUG_RETURN(TRUE);
+          }
+        }
+      }
+    }
+#endif /* WITH_WSREP */
+
+    if (lock_table(thd, table_ref, &hton_can_recreate))
+      DBUG_RETURN(TRUE);
+
+    if (hton_can_recreate)
+    {
+     /*
+        The storage engine can truncate the table by creating an
+        empty table with the same structure.
+      */
+      error= dd_recreate_table(thd, table_ref->db.str, table_ref->table_name.str);
+
+      if (thd->locked_tables_mode && thd->locked_tables_list.reopen_tables(thd, false))
+      {
+        thd->locked_tables_list.unlink_all_closed_tables(thd, NULL, 0);
+        error=1;
+      }
+
+      /* No need to binlog a failed truncate-by-recreate. */
+      binlog_stmt= !error;
+    }
+    else
+    {
+      /*
+        The engine does not support truncate-by-recreate.
+        Attempt to use the handler truncate method.
+      */
+      error= handler_truncate(thd, table_ref, FALSE);
+
+      if (error == TRUNCATE_OK && thd->locked_tables_mode &&
+          (table_ref->table->file->ht->flags &
+           HTON_REQUIRES_CLOSE_AFTER_TRUNCATE))
+      {
+        thd->locked_tables_list.mark_table_for_reopen(thd, table_ref->table);
+        if (unlikely(thd->locked_tables_list.reopen_tables(thd, true)))
+          thd->locked_tables_list.unlink_all_closed_tables(thd, NULL, 0);
+      }
+
+      /*
+        All effects of a TRUNCATE TABLE operation are committed even if
+        truncation fails in the case of non transactional tables. Thus, the
+        query must be written to the binary log. The only exception is a
+        unimplemented truncate method.
+      */
+      if (unlikely(error == TRUNCATE_OK || error == TRUNCATE_FAILED_BUT_BINLOG))
+        binlog_stmt= true;
+      else
+        binlog_stmt= false;
+    }
+
+    /*
+      If we tried to open a MERGE table and failed due to problems with the
+      children tables, the table will have been closed and table_ref->table
+      will be invalid. Reset the pointer here in any case as
+      query_cache_invalidate does not need a valid TABLE object.
+    */
+    table_ref->table= NULL;
+    query_cache_invalidate3(thd, table_ref, FALSE);
+  }
+
+  /* DDL is logged in statement format, regardless of binlog format. */
+  if (binlog_stmt)
+    error|= write_bin_log(thd, !error, thd->query(), thd->query_length());
+
+  /*
+    A locked table ticket was upgraded to a exclusive lock. After the
+    the query has been written to the binary log, downgrade the lock
+    to a shared one.
+  */
+  if (m_ticket_downgrade)
+    m_ticket_downgrade->downgrade_lock(MDL_SHARED_NO_READ_WRITE);
+
+  DBUG_RETURN(error);
+}
+
+/**
+  Execute a TRUNCATE statement at runtime.
+
+  @param  thd   The current thread.
+
+  @return FALSE on success.
+*/
+
+bool Sql_cmd_truncate_table::execute(THD *thd)
+{
+  bool res= TRUE;
+  TABLE_LIST *table= thd->lex->first_select_lex()->table_list.first;
+  DBUG_ENTER("Sql_cmd_truncate_table::execute");
+
+  if (check_one_table_access(thd, DROP_ACL, table))
+    DBUG_RETURN(res);
+
+  if (! (res= truncate_table(thd, table)))
+    my_ok(thd);
+
+  DBUG_RETURN(res);
+}