• unknown's avatar
    Task ID 499:Add a new settable string variable(init_connect, init_slave) · a0e4a6de
    unknown authored
    to mysqld that is executed for all new connections.
    (Similar to the client command: mysql_options(... MYSQL_INIT_COMMAND ...).
    
    
    sql/mysql_priv.h:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    sql/mysqld.cc:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    sql/protocol.cc:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    sql/set_var.cc:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    sql/slave.cc:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    sql/sql_class.cc:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    sql/sql_class.h:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    sql/sql_parse.cc:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    sql/sql_show.cc:
      Task ID	499:Add a new settable string variable(init_connect, init_slave)
      to mysqld that is executed for all new connections.
    a0e4a6de
sql_class.h 30.8 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB

   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; either version 2 of the License, or
   (at your option) any later version.

   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


/* Classes in mysql */

#ifdef __GNUC__
#pragma interface			/* gcc class implementation */
#endif

// TODO: create log.h and move all the log header stuff there

class Query_log_event;
class Load_log_event;
class Slave_log_event;

enum enum_enable_or_disable { LEAVE_AS_IS, ENABLE, DISABLE };
enum enum_ha_read_modes { RFIRST, RNEXT, RPREV, RLAST, RKEY };
enum enum_duplicates { DUP_ERROR, DUP_REPLACE, DUP_IGNORE, DUP_UPDATE };
enum enum_log_type { LOG_CLOSED, LOG_NORMAL, LOG_NEW, LOG_BIN };
enum enum_delay_key_write { DELAY_KEY_WRITE_NONE, DELAY_KEY_WRITE_ON,
			    DELAY_KEY_WRITE_ALL };

extern char internal_table_name[2];

// log info errors
#define LOG_INFO_EOF -1
#define LOG_INFO_IO  -2
#define LOG_INFO_INVALID -3
#define LOG_INFO_SEEK -4
#define LOG_INFO_PURGE_NO_ROTATE -5
#define LOG_INFO_MEM -6
#define LOG_INFO_FATAL -7
#define LOG_INFO_IN_USE -8

struct st_relay_log_info;

typedef struct st_log_info
{
  char log_file_name[FN_REFLEN];
  my_off_t index_file_offset, index_file_start_offset;
  my_off_t pos;
  bool fatal; // if the purge happens to give us a negative offset
  pthread_mutex_t lock;
  st_log_info():fatal(0) { pthread_mutex_init(&lock, MY_MUTEX_INIT_FAST);}
  ~st_log_info() { pthread_mutex_destroy(&lock);}
} LOG_INFO;

typedef struct st_user_var_events
{
  user_var_entry *user_var_event;
  char *value;
  ulong length;
  Item_result type;
  uint charset_number;
} BINLOG_USER_VAR_EVENT;

class Log_event;

class MYSQL_LOG {
 private:
  pthread_mutex_t LOCK_log, LOCK_index;
  pthread_cond_t update_cond;
  ulonglong bytes_written;
  time_t last_time,query_start;
  IO_CACHE log_file;
  IO_CACHE index_file;
  char *name;
  char time_buff[20],db[NAME_LEN+1];
  char log_file_name[FN_REFLEN],index_file_name[FN_REFLEN];
  // current file sequence number for load data infile binary logging
  uint file_id;
  uint open_count;				// For replication
  volatile enum_log_type log_type;
  enum cache_type io_cache_type;
  bool write_error,inited;
  /*
    For binlog - if log name can never change we should not try to rotate it
    or write any rotation events. The user should use FLUSH MASTER instead
    of FLUSH LOGS for purging.
  */
  bool no_rotate;
  bool need_start_event;
  bool no_auto_events; // for relay binlog
  friend class Log_event;

public:
  MYSQL_LOG();
  ~MYSQL_LOG();
  void reset_bytes_written()
  {
    bytes_written = 0;
  }
  void harvest_bytes_written(ulonglong* counter)
  {
#ifndef DBUG_OFF
    char buf1[22],buf2[22];
#endif	
    DBUG_ENTER("harvest_bytes_written");
    (*counter)+=bytes_written;
    DBUG_PRINT("info",("counter: %s  bytes_written: %s", llstr(*counter,buf1),
		       llstr(bytes_written,buf2)));
    bytes_written=0;
    DBUG_VOID_RETURN;
  }
  void signal_update() { pthread_cond_broadcast(&update_cond);}
  void wait_for_update(THD* thd);
  void set_need_start_event() { need_start_event = 1; }
  void init(enum_log_type log_type_arg,
	    enum cache_type io_cache_type_arg = WRITE_CACHE,
	    bool no_auto_events_arg = 0);
  void cleanup();
  bool open(const char *log_name,enum_log_type log_type,
	    const char *new_name, const char *index_file_name_arg,
	    enum cache_type io_cache_type_arg,
	    bool no_auto_events_arg);
  void new_file(bool need_lock= 1);
  bool write(THD *thd, enum enum_server_command command,
	     const char *format,...);
  bool write(THD *thd, const char *query, uint query_length,
	     time_t query_start=0);
  bool write(Log_event* event_info); // binary log write
  bool write(THD *thd, IO_CACHE *cache);

  /*
    v stands for vector
    invoked as appendv(buf1,len1,buf2,len2,...,bufn,lenn,0)
  */
  bool appendv(const char* buf,uint len,...);
  bool append(Log_event* ev);
  
  int generate_new_name(char *new_name,const char *old_name);
  void make_log_name(char* buf, const char* log_ident);
  bool is_active(const char* log_file_name);
  int update_log_index(LOG_INFO* linfo, bool need_update_threads);
  int purge_logs(const char *to_log, bool included, 
                 bool need_mutex, bool need_update_threads,
                 ulonglong *decrease_log_space);
  int purge_logs_before_date(time_t purge_time);
  int purge_first_log(struct st_relay_log_info* rli, bool included); 
  bool reset_logs(THD* thd);
  // if we are exiting, we also want to close the index file
  void close(bool exiting = 0);

  // iterating through the log index file
  int find_log_pos(LOG_INFO* linfo, const char* log_name,
		   bool need_mutex);
  int find_next_log(LOG_INFO* linfo, bool need_mutex);
  int get_current_log(LOG_INFO* linfo);
  uint next_file_id();

  inline bool is_open() { return log_type != LOG_CLOSED; }
  inline char* get_index_fname() { return index_file_name;}
  inline char* get_log_fname() { return log_file_name; }
  inline pthread_mutex_t* get_log_lock() { return &LOCK_log; }
  inline IO_CACHE* get_log_file() { return &log_file; }

  inline void lock_index() { pthread_mutex_lock(&LOCK_index);}
  inline void unlock_index() { pthread_mutex_unlock(&LOCK_index);}
  inline IO_CACHE *get_index_file() { return &index_file;}
  inline uint32 get_open_count() { return open_count; }
};

/* character conversion tables */


typedef struct st_copy_info {
  ha_rows records;
  ha_rows deleted;
  ha_rows copied;
  ha_rows error_count;
  enum enum_duplicates handle_duplicates;
  int escape_char, last_errno;
/* for INSERT ... UPDATE */
  List<Item> *update_fields;
  List<Item> *update_values;
} COPY_INFO;


class key_part_spec :public Sql_alloc {
public:
  const char *field_name;
  uint length;
  key_part_spec(const char *name,uint len=0) :field_name(name), length(len) {}
};


class Alter_drop :public Sql_alloc {
public:
  enum drop_type {KEY, COLUMN };
  const char *name;
  enum drop_type type;
  Alter_drop(enum drop_type par_type,const char *par_name)
    :name(par_name), type(par_type) {}
};


class Alter_column :public Sql_alloc {
public:
  const char *name;
  Item *def;
  Alter_column(const char *par_name,Item *literal)
    :name(par_name), def(literal) {}
};


class Key :public Sql_alloc {
public:
  enum Keytype { PRIMARY, UNIQUE, MULTIPLE, FULLTEXT, SPATIAL, FOREIGN_KEY};
  enum Keytype type;
  enum ha_key_alg algorithm;
  List<key_part_spec> columns;
  const char *name;

  Key(enum Keytype type_par, const char *name_arg, enum ha_key_alg alg_par,
      List<key_part_spec> &cols)
    :type(type_par), algorithm(alg_par), columns(cols), name(name_arg)
  {}
  ~Key() {}
};

class Table_ident;

class foreign_key: public Key {
public:
  enum fk_match_opt { FK_MATCH_UNDEF, FK_MATCH_FULL,
		      FK_MATCH_PARTIAL, FK_MATCH_SIMPLE};
  enum fk_option { FK_OPTION_UNDEF, FK_OPTION_RESTRICT, FK_OPTION_CASCADE,
		   FK_OPTION_SET_NULL, FK_OPTION_NO_ACTION, FK_OPTION_DEFAULT};

  Table_ident *ref_table;
  List<key_part_spec> ref_columns;
  uint delete_opt, update_opt, match_opt;
  foreign_key(const char *name_arg, List<key_part_spec> &cols,
	      Table_ident *table,   List<key_part_spec> &ref_cols,
	      uint delete_opt_arg, uint update_opt_arg, uint match_opt_arg)
    :Key(FOREIGN_KEY, name_arg, HA_KEY_ALG_UNDEF, cols),
    ref_table(table), ref_columns(cols),
    delete_opt(delete_opt_arg), update_opt(update_opt_arg),
    match_opt(match_opt_arg)
  {}
};

typedef struct st_mysql_lock
{
  TABLE **table;
  uint table_count,lock_count;
  THR_LOCK_DATA **locks;
} MYSQL_LOCK;


class LEX_COLUMN : public Sql_alloc
{
public:
  String column;
  uint rights;
  LEX_COLUMN (const String& x,const  uint& y ): column (x),rights (y) {}
};

#include "sql_lex.h"				/* Must be here */

/* Needed to be able to have an I_List of char* strings in mysqld.cc. */

class i_string: public ilink
{
public:
  char* ptr;
  i_string():ptr(0) { }
  i_string(char* s) : ptr(s) {}
};

/* needed for linked list of two strings for replicate-rewrite-db */
class i_string_pair: public ilink
{
public:
  char* key;
  char* val;
  i_string_pair():key(0),val(0) { }
  i_string_pair(char* key_arg, char* val_arg) : key(key_arg),val(val_arg) {}
};


class MYSQL_ERROR: public Sql_alloc
{
public:
  enum enum_warning_level
  { WARN_LEVEL_NOTE, WARN_LEVEL_WARN, WARN_LEVEL_ERROR, WARN_LEVEL_END};

  uint code;
  enum_warning_level level;
  char *msg;
  
  MYSQL_ERROR(THD *thd, uint code_arg, enum_warning_level level_arg,
	      const char *msg_arg)
    :code(code_arg), level(level_arg)
  {
    if (msg_arg)
      set_msg(thd, msg_arg);
  }
  void set_msg(THD *thd, const char *msg_arg);
};


/* This is a struct as it's allocated in tree_insert */

typedef struct st_prep_stmt
{
  THD *thd;
  LEX  lex; 
  Item_param **param;
  Item *free_list;
  MEM_ROOT mem_root;
  String *query;
  ulong stmt_id;
  uint param_count;
  uint last_errno;
  char last_error[MYSQL_ERRMSG_SIZE];
  bool error_in_prepare, long_data_used;
  bool log_full_query;
  bool (*setup_params)(st_prep_stmt *stmt, uchar *pos, uchar *read_pos);
} PREP_STMT;


class delayed_insert;
class select_result;

#define THD_SENTRY_MAGIC 0xfeedd1ff
#define THD_SENTRY_GONE  0xdeadbeef

#define THD_CHECK_SENTRY(thd) DBUG_ASSERT(thd->dbug_sentry == THD_SENTRY_MAGIC)

struct system_variables
{
  ulonglong myisam_max_extra_sort_file_size;
  ulonglong myisam_max_sort_file_size;
  ha_rows select_limit;
  ha_rows max_join_size;
  ulong bulk_insert_buff_size;
  ulong join_buff_size;
  ulong long_query_time;
  ulong max_allowed_packet;
  ulong max_error_count;
  ulong max_heap_table_size;
  ulong max_length_for_sort_data;
  ulong max_prep_stmt_count;
  ulong max_sort_length;
  ulong max_tmp_tables;
  ulong myisam_repair_threads;
  ulong myisam_sort_buff_size;
  ulong net_buffer_length;
  ulong net_interactive_timeout;
  ulong net_read_timeout;
  ulong net_retry_count;
  ulong net_wait_timeout;
  ulong net_write_timeout;
  ulong preload_buff_size;
  ulong query_cache_type;
  ulong read_buff_size;
  ulong read_rnd_buff_size;
  ulong sortbuff_size;
  ulong table_type;
  ulong tmp_table_size;
  ulong tx_isolation;
  ulong sql_mode;
  ulong default_week_format;
  ulong group_concat_max_len;
  /*
    In slave thread we need to know in behalf of which
    thread the query is being run to replicate temp tables properly
  */
  ulong pseudo_thread_id;

  my_bool log_warnings;
  my_bool low_priority_updates;
  my_bool new_mode;
  
  CHARSET_INFO	*character_set_server;
  CHARSET_INFO	*character_set_database;
  CHARSET_INFO 	*character_set_client;
  CHARSET_INFO  *character_set_results;
  CHARSET_INFO  *collation_connection;
};

void free_tmp_table(THD *thd, TABLE *entry);
/*
  For each client connection we create a separate thread with THD serving as
  a thread/connection descriptor
*/

class THD :public ilink
{
public:
#ifdef EMBEDDED_LIBRARY
  struct st_mysql  *mysql;
#endif
  NET	  net;				// client connection descriptor
  LEX	  lex;				// parse tree descriptor
  MEM_ROOT mem_root;			// 1 command-life memory pool
  MEM_ROOT con_root;                    // connection-life memory
  MEM_ROOT warn_root;			// For warnings and errors
  Protocol *protocol;			// Current protocol
  Protocol_simple protocol_simple;	// Normal protocol
  Protocol_prep protocol_prep;		// Binary protocol
  HASH    user_vars;			// hash for user variables
  TREE	  prepared_statements;
  String  packet;			// dynamic buffer for network I/O
  struct  sockaddr_in remote;		// client socket address
  struct  rand_struct rand;		// used for authentication
  struct  system_variables variables;	// Changeable local variables
  pthread_mutex_t LOCK_delete;		// Locked before thd is deleted

  char	  *query;			// Points to the current query,
  /*
    A pointer to the stack frame of handle_one_connection(),
    which is called first in the thread for handling a client
  */
  char	  *thread_stack;

  /*
    host - host of the client
    user - user of the client, set to NULL until the user has been read from
     the connection
    priv_user - The user privilege we are using. May be '' for anonymous user.
    db - currently selected database
    ip - client IP
   */
  char	  *host,*user,*priv_user,*db,*ip;
  char	  priv_host[MAX_HOSTNAME];
  /* remote (peer) port */
  uint16 peer_port;
  /* Points to info-string that will show in SHOW PROCESSLIST */
  const char *proc_info;
  /* points to host if host is available, otherwise points to ip */
  const char *host_or_ip;

  ulong client_capabilities;		/* What the client supports */
  /* Determines if which non-standard SQL behaviour should be enabled */
  ulong max_client_packet_length;
  ulong master_access;			/* Global privileges from mysql.user */
  ulong db_access;			/* Privileges for current db */

  /*
    open_tables - list of regular tables in use by this thread
    temporary_tables - list of temp tables in use by this thread
    handler_tables - list of tables that were opened with HANDLER OPEN
     and are still in use by this thread
  */
  TABLE   *open_tables,*temporary_tables, *handler_tables, *derived_tables;
  // TODO: document the variables below
  MYSQL_LOCK	*lock;				/* Current locks */
  MYSQL_LOCK	*locked_tables;			/* Tables locked with LOCK */
  ULL		*ull;
  PREP_STMT	*last_prepared_stmt;
#ifndef DBUG_OFF
  uint dbug_sentry; // watch out for memory corruption
#endif  
  struct st_my_thread_var *mysys_var;
  enum enum_server_command command;
  uint32     server_id;
  uint32     file_id;			// for LOAD DATA INFILE
  const char *where;
  time_t     start_time,time_after_lock,user_time;
  time_t     connect_time,thr_create_time; // track down slow pthread_create
  thr_lock_type update_lock_default;
  delayed_insert *di;
  struct st_transactions {
    IO_CACHE trans_log;
    THD_TRANS all;			// Trans since BEGIN WORK
    THD_TRANS stmt;			// Trans for current statement
    uint bdb_lock_count;

    /* 
       Tables changed in transaction (that must be invalidated in query cache).
       List contain only transactional tables, that not invalidated in query 
       cache (instead of full list of changed in transaction tables).
    */
    CHANGED_TABLE_LIST* changed_tables;
    MEM_ROOT mem_root; // Transaction-life memory allocation pool
    void cleanup()
    {
      changed_tables = 0;
      free_root(&mem_root,MYF(MY_KEEP_PREALLOC));
    }
  } transaction;
  Item	     *free_list, *handler_items;
  Field      *dupp_field;
#ifndef __WIN__
  sigset_t signals,block_signals;
#endif
#ifdef SIGNAL_WITH_VIO_CLOSE
  Vio* active_vio;
#endif  
  /*
    next_insert_id is set on SET INSERT_ID= #. This is used as the next
    generated auto_increment value in handler.cc
  */
  ulonglong  next_insert_id;
  /*
    The insert_id used for the last statement or set by SET LAST_INSERT_ID=#
    or SELECT LAST_INSERT_ID(#).  Used for binary log and returned by
    LAST_INSERT_ID()
  */
  ulonglong  last_insert_id;
  /*
    Set to the first value that LAST_INSERT_ID() returned for the last
    statement.  When this is set, last_insert_id_used is set to true.
  */
  ulonglong  current_insert_id;
  ulonglong  limit_found_rows;
  ha_rows    select_limit, offset_limit, cuted_fields,
             sent_row_count, examined_row_count;
  table_map  used_tables;
  USER_CONN *user_connect;
  CHARSET_INFO *db_charset;   
  List<TABLE> temporary_tables_should_be_free; // list of temporary tables
  List	     <MYSQL_ERROR> warn_list;  
  uint	     warn_count[(uint) MYSQL_ERROR::WARN_LEVEL_END];
  uint	     total_warn_count, old_total_warn_count;
  ulong	     query_id, warn_id, version, options, thread_id, col_access;
  ulong      current_stmt_id;
  ulong	     rand_saved_seed1, rand_saved_seed2;
  ulong      row_count;  // Row counter, mainly for errors and warnings
  long	     dbug_thread_id;
  pthread_t  real_id;
  uint	     current_tablenr,tmp_table;
  uint	     server_status,open_options;
  uint32     query_length;
  uint32     db_length;
  uint       select_number;             //number of select (used for EXPLAIN)
  /* variables.transaction_isolation is reset to this after each commit */
  enum_tx_isolation session_tx_isolation;
  /* for user variables replication*/
  DYNAMIC_ARRAY user_var_events;
             // extend scramble to handle new auth
  char	     scramble[SCRAMBLE41_LENGTH+1];
             // old scramble is needed to handle old clients
  char       old_scramble[SCRAMBLE_LENGTH+1];
  uint8	     query_cache_type;		// type of query cache processing
  bool       slave_thread;
  bool	     set_query_id,locked,count_cuted_fields,some_tables_deleted;
  bool       last_cuted_field;
  bool	     no_errors, allow_sum_func, password, is_fatal_error;
  bool	     query_start_used,last_insert_id_used,insert_id_used,rand_used;
  bool	     system_thread,in_lock_tables,global_read_lock;
  bool       query_error, bootstrap, cleanup_done;
  bool	     volatile killed;
  bool       prepare_command;
  bool	     tmp_table_used;

  /*
    If we do a purge of binary logs, log index info of the threads
    that are currently reading it needs to be adjusted. To do that
    each thread that is using LOG_INFO needs to adjust the pointer to it
  */
  LOG_INFO*  current_linfo;
  NET*       slave_net;			// network connection from slave -> m.
  my_off_t   log_pos;
  /* Used by the sys_var class to store temporary values */
  union
  {
    my_bool my_bool_value;
    long    long_value;
  } sys_var_tmp;

  THD();
  ~THD();

  void init(void);
  void change_user(void);
  void init_for_queries();
  void cleanup(void);
  bool store_globals();
#ifdef SIGNAL_WITH_VIO_CLOSE
  inline void set_active_vio(Vio* vio)
  {
    pthread_mutex_lock(&LOCK_delete);
    active_vio = vio;
    pthread_mutex_unlock(&LOCK_delete);
  }
  inline void clear_active_vio()
  {
    pthread_mutex_lock(&LOCK_delete);
    active_vio = 0;
    pthread_mutex_unlock(&LOCK_delete);
  }
  void close_active_vio();
#endif  
  void awake(bool prepare_to_die);
  inline const char* enter_cond(pthread_cond_t *cond, pthread_mutex_t* mutex,
			  const char* msg)
  {
    const char* old_msg = proc_info;
    mysys_var->current_mutex = mutex;
    mysys_var->current_cond = cond;
    proc_info = msg;
    return old_msg;
  }
  inline void exit_cond(const char* old_msg)
  {
    pthread_mutex_lock(&mysys_var->mutex);
    mysys_var->current_mutex = 0;
    mysys_var->current_cond = 0;
    proc_info = old_msg;
    pthread_mutex_unlock(&mysys_var->mutex);
  }
  inline time_t query_start() { query_start_used=1; return start_time; }
  inline void	set_time()    { if (user_time) start_time=time_after_lock=user_time; else time_after_lock=time(&start_time); }
  inline void	end_time()    { time(&start_time); }
  inline void	set_time(time_t t) { time_after_lock=start_time=user_time=t; }
  inline void	lock_time()   { time(&time_after_lock); }
  inline void	insert_id(ulonglong id)
  { last_insert_id=id; insert_id_used=1; }
  inline ulonglong insert_id(void)
  {
    if (!last_insert_id_used)
    {      
      last_insert_id_used=1;
      current_insert_id=last_insert_id;
    }
    return last_insert_id;
  }
  inline ulonglong found_rows(void)
  {
    return limit_found_rows;
  }                                                                         
  inline bool active_transaction()
  {
#ifdef USING_TRANSACTIONS    
    return (transaction.all.bdb_tid != 0 ||
	    transaction.all.innodb_active_trans != 0);
#else
    return 0;
#endif
  }
  inline gptr alloc(unsigned int size) { return alloc_root(&mem_root,size); }
  inline gptr calloc(unsigned int size)
  {
    gptr ptr;
    if ((ptr=alloc_root(&mem_root,size)))
      bzero((char*) ptr,size);
    return ptr;
  }
  inline char *strdup(const char *str)
  { return strdup_root(&mem_root,str); }
  inline char *strmake(const char *str, uint size)
  { return strmake_root(&mem_root,str,size); }
  inline char *memdup(const char *str, uint size)
  { return memdup_root(&mem_root,str,size); }
  inline char *memdup_w_gap(const char *str, uint size, uint gap)
  {
    gptr ptr;
    if ((ptr=alloc_root(&mem_root,size+gap)))
      memcpy(ptr,str,size);
    return ptr;
  }
  inline gptr trans_alloc(unsigned int size) 
  { 
    return alloc_root(&transaction.mem_root,size);
  }
  void add_changed_table(TABLE *table);
  void add_changed_table(const char *key, long key_length);
  CHANGED_TABLE_LIST * changed_table_dup(const char *key, long key_length);
  int send_explain_fields(select_result *result);
#ifndef EMBEDDED_LIBRARY
  inline void clear_error()
  {
    net.last_error[0]= 0;
    net.last_errno= 0;
    net.report_error= 0;
  }
#else
  void clear_error();
#endif
  inline void fatal_error()
  {
    is_fatal_error= 1;
    net.report_error= 1; 
    DBUG_PRINT("error",("Fatal error set"));
  }
  inline CHARSET_INFO *charset() { return variables.character_set_client; }
};

/*
  Used to hold information about file and file structure in exchainge 
  via non-DB file (...INTO OUTFILE..., ...LOAD DATA...)
*/
class sql_exchange :public Sql_alloc
{
public:
  char *file_name;
  String *field_term,*enclosed,*line_term,*line_start,*escaped;
  bool opt_enclosed;
  bool dumpfile;
  uint skip_lines;
  sql_exchange(char *name,bool dumpfile_flag);
  ~sql_exchange() {}
};

#include "log_event.h"

/*
  This is used to get result from a select
*/

class JOIN;

void send_error(THD *thd, uint sql_errno=0, const char *err=0);

class select_result :public Sql_alloc {
protected:
  THD *thd;
  SELECT_LEX_UNIT *unit;
public:
  select_result();
  virtual ~select_result() {};
  virtual int prepare(List<Item> &list, SELECT_LEX_UNIT *u)
  {
    unit= u;
    return 0;
  }
  virtual bool send_fields(List<Item> &list,uint flag)=0;
  virtual bool send_data(List<Item> &items)=0;
  virtual bool initialize_tables (JOIN *join=0) { return 0; }
  virtual void send_error(uint errcode,const char *err)
  {
    my_message(errcode, err, MYF(0));
  }
  virtual bool send_eof()=0;
  virtual void abort() {}
};


class select_send :public select_result {
public:
  select_send() {}
  bool send_fields(List<Item> &list,uint flag);
  bool send_data(List<Item> &items);
  bool send_eof();
};


class select_export :public select_result {
  sql_exchange *exchange;
  File file;
  IO_CACHE cache;
  ha_rows row_count;
  uint field_term_length;
  int field_sep_char,escape_char,line_sep_char;
  bool fixed_row_size;
public:
  select_export(sql_exchange *ex) :exchange(ex),file(-1),row_count(0L) {}
  ~select_export();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list,
		   uint flag) { return 0; }
  bool send_data(List<Item> &items);
  void send_error(uint errcode,const char *err);
  bool send_eof();
};


class select_dump :public select_result {
  sql_exchange *exchange;
  File file;
  IO_CACHE cache;
  ha_rows row_count;
  char path[FN_REFLEN];
public:
  select_dump(sql_exchange *ex) :exchange(ex),file(-1),row_count(0L)
  { path[0]=0; }
  ~select_dump();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list,
		   uint flag) { return 0; }
  bool send_data(List<Item> &items);
  void send_error(uint errcode,const char *err);
  bool send_eof();
};


class select_insert :public select_result {
 public:
  TABLE *table;
  List<Item> *fields;
  ulonglong last_insert_id;
  COPY_INFO info;

  select_insert(TABLE *table_par,List<Item> *fields_par,enum_duplicates duplic)
    :table(table_par),fields(fields_par), last_insert_id(0)
  {
    bzero((char*) &info,sizeof(info));
    info.handle_duplicates=duplic;
  }
  ~select_insert();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list, uint flag)
  { return 0; }
  bool send_data(List<Item> &items);
  void send_error(uint errcode,const char *err);
  bool send_eof();
};


class select_create: public select_insert {
  ORDER *group;
  const char *db;
  const char *name;
  List<create_field> *extra_fields;
  List<Key> *keys;
  HA_CREATE_INFO *create_info;
  MYSQL_LOCK *lock;
  Field **field;
public:
  select_create (const char *db_name, const char *table_name,
		 HA_CREATE_INFO *create_info_par,
		 List<create_field> &fields_par,
		 List<Key> &keys_par,
		 List<Item> &select_fields,enum_duplicates duplic)
    :select_insert (NULL, &select_fields, duplic), db(db_name),
    name(table_name), extra_fields(&fields_par),keys(&keys_par),
    create_info(create_info_par),
    lock(0)
    {}
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_data(List<Item> &values);
  bool send_eof();
  void abort();
};

#include <myisam.h>

/* Param to create temporary tables when doing SELECT:s */

class TMP_TABLE_PARAM :public Sql_alloc
{
 public:
  List<Item> copy_funcs;
  List<Item> save_copy_funcs;
  List_iterator_fast<Item> copy_funcs_it;
  Copy_field *copy_field, *copy_field_end;
  Copy_field *save_copy_field, *save_copy_field_end;
  byte	    *group_buff;
  Item	    **items_to_copy;			/* Fields in tmp table */
  MI_COLUMNDEF *recinfo,*start_recinfo;
  KEY *keyinfo;
  ha_rows end_write_records;
  uint	field_count,sum_func_count,func_count;
  uint  hidden_field_count;
  uint	group_parts,group_length,group_null_parts;
  uint	quick_group;
  bool  using_indirect_summary_function;

  TMP_TABLE_PARAM()
    :copy_funcs_it(copy_funcs), copy_field(0), group_parts(0),
    group_length(0), group_null_parts(0)
  {}
  ~TMP_TABLE_PARAM()
  {
    cleanup();
  }
  inline void cleanup(void)
  {
    if (copy_field)				/* Fix for Intel compiler */
    {
      delete [] copy_field;
      copy_field=0;
    }
  }
};

class select_union :public select_result {
 public:
  TABLE *table;
  COPY_INFO info;
  TMP_TABLE_PARAM tmp_table_param;
  bool not_describe;

  select_union(TABLE *table_par);
  ~select_union();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list, uint flag)
  { return 0; }
  bool send_data(List<Item> &items);
  bool send_eof();
  bool flush();
};

/* Base subselect interface class */
class select_subselect :public select_result
{
protected:
  Item_subselect *item;
public:
  select_subselect(Item_subselect *item);
  bool send_fields(List<Item> &list, uint flag) { return 0; };
  bool send_data(List<Item> &items)=0;
  bool send_eof() { return 0; };

  friend class Ttem_subselect;
};

/* Single value subselect interface class */
class select_singlerow_subselect :public select_subselect
{
public:
  select_singlerow_subselect(Item_subselect *item):select_subselect(item){}
  bool send_data(List<Item> &items);
};

/* EXISTS subselect interface class */
class select_exists_subselect :public select_subselect
{
public:
  select_exists_subselect(Item_subselect *item):select_subselect(item){}
  bool send_data(List<Item> &items);
};

/* Structs used when sorting */

typedef struct st_sort_field {
  Field *field;				/* Field to sort */
  Item	*item;				/* Item if not sorting fields */
  uint	 length;			/* Length of sort field */
  Item_result result_type;		/* Type of item */
  bool reverse;				/* if descending sort */
  bool need_strxnfrm;			/* If we have to use strxnfrm() */
} SORT_FIELD;


typedef struct st_sort_buffer {
  uint index;					/* 0 or 1 */
  uint sort_orders;
  uint change_pos;				/* If sort-fields changed */
  char **buff;
  SORT_FIELD *sortorder;
} SORT_BUFFER;


/* Structure for db & table in sql_yacc */

class Table_ident :public Sql_alloc
{
 public:
  LEX_STRING db;
  LEX_STRING table;
  SELECT_LEX_UNIT *sel;
  inline Table_ident(THD *thd, LEX_STRING db_arg, LEX_STRING table_arg,
		     bool force)
    :table(table_arg), sel((SELECT_LEX_UNIT *)0)
  {
    if (!force && (thd->client_capabilities & CLIENT_NO_SCHEMA))
      db.str=0;
    else
      db= db_arg;
  }
  inline Table_ident(LEX_STRING table_arg) 
    :table(table_arg), sel((SELECT_LEX_UNIT *)0)
  {
    db.str=0;
  }
  inline Table_ident(SELECT_LEX_UNIT *s) : sel(s) 
  {
    /* We must have a table name here as this is used with add_table_to_list */
    db.str=0; table.str= internal_table_name; table.length=1;
  }
  inline void change_db(char *db_name)
  {
    db.str= db_name; db.length= (uint) strlen(db_name);
  }
};

// this is needed for user_vars hash
class user_var_entry
{
 public:
  LEX_STRING name;
  char *value;
  ulong length, update_query_id, used_query_id;
  Item_result type;
  DTCollation collation;
};

/* Class for unique (removing of duplicates) */

class Unique :public Sql_alloc
{
  DYNAMIC_ARRAY file_ptrs;
  ulong max_elements, max_in_memory_size;
  IO_CACHE file;
  TREE tree;
  byte *record_pointers;
  bool flush();

public:
  ulong elements;
  Unique(qsort_cmp2 comp_func, void * comp_func_fixed_arg,
	 uint size, ulong max_in_memory_size_arg);
  ~Unique();
  inline bool unique_add(gptr ptr)
  {
    if (tree.elements_in_tree > max_elements && flush())
      return 1;
    return !tree_insert(&tree, ptr, 0, tree.custom_arg);
  }

  bool get(TABLE *table);

  friend int unique_write_to_file(gptr key, element_count count, Unique *unique);
  friend int unique_write_to_ptrs(gptr key, element_count count, Unique *unique);
};

class multi_delete : public select_result
{
  TABLE_LIST *delete_tables, *table_being_deleted;
  Unique  **tempfiles;
  THD *thd;
  ha_rows deleted;
  uint num_of_tables;
  int error;
  bool do_delete, transactional_tables, log_delayed, normal_tables;
public:
  multi_delete(THD *thd, TABLE_LIST *dt, uint num_of_tables);
  ~multi_delete();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list,
 		   uint flag) { return 0; }
  bool send_data(List<Item> &items);
  bool initialize_tables (JOIN *join);
  void send_error(uint errcode,const char *err);
  int  do_deletes (bool from_send_error);
  bool send_eof();
};


class multi_update : public select_result
{
  TABLE_LIST *all_tables, *update_tables, *table_being_updated;
  THD *thd;
  TABLE **tmp_tables, *main_table, *table_to_update;
  TMP_TABLE_PARAM *tmp_table_param;
  ha_rows updated, found;
  List <Item> *fields, *values;
  List <Item> **fields_for_table, **values_for_table;
  uint table_count;
  Copy_field *copy_field;
  enum enum_duplicates handle_duplicates;
  bool do_update, trans_safe, transactional_tables, log_delayed;

public:
  multi_update(THD *thd_arg, TABLE_LIST *ut, List<Item> *fields,
	       List<Item> *values, enum_duplicates handle_duplicates);
  ~multi_update();
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list, uint flag) { return 0; }
  bool send_data(List<Item> &items);
  bool initialize_tables (JOIN *join);
  void send_error(uint errcode,const char *err);
  int  do_updates (bool from_send_error);
  bool send_eof();
};


class select_dumpvar :public select_result {
  ha_rows row_count;
public:
  List<LEX_STRING> var_list;
  List<Item_func_set_user_var> vars;
  select_dumpvar(void)  { var_list.empty(); vars.empty(); row_count=0;}
  ~select_dumpvar() {}
  int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
  bool send_fields(List<Item> &list, uint flag) {return 0;}
  bool send_data(List<Item> &items);
  bool send_eof();
};