table checksum background:

my_checksum() mysys function
   NISAM checksum code moved from mysys to isam/ - it's obsolete
   MyISAM checksum code moved to mysys
   table's checksum accessible from sql layer
   SHOW TABLE STATUS shows checksum (WL#646)
code cleanup

include/my_sys.h

@@ -507,6 +507,8 @@ typedef struct st_keycache
   ulonglong size;
 } KEY_CACHE;
 
+typedef uint32 ha_checksum;
+
 #include <my_alloc.h>
 
 	/* Prototypes for mysys and my_func functions */
@@ -749,7 +751,7 @@ extern void print_defaults(const char *conf_file, const char **groups);
 extern my_bool my_compress(byte *, ulong *, ulong *);
 extern my_bool my_uncompress(byte *, ulong *, ulong *);
 extern byte *my_compress_alloc(const byte *packet, ulong *len, ulong *complen);
-extern ulong checksum(const byte *mem, uint count);
+extern ha_checksum my_checksum(ha_checksum crc, const byte *mem, uint count);
 extern uint my_bit_log2(ulong value);
 uint my_count_bits(ulonglong v);
 extern void my_sleep(ulong m_seconds);

include/myisam.h

@@ -53,8 +53,6 @@ extern "C" {
 
 #define mi_portable_sizeof_char_ptr 8
 
-typedef uint32 ha_checksum;
-
 	/* Param to/from mi_info */
 
 typedef struct st_mi_isaminfo		/* Struct from h_info */

isam/isamchk.c

@@ -1328,7 +1328,7 @@ int extend;
 	print_error("Found wrong record at %lu",(ulong) start_recpos);
 	got_error=1;
       }
-      crc^=checksum(record,info->s->base.reclength);
+      crc^=_nisam_checksum(record,info->s->base.reclength);
       link_used+=info->s->pack.ref_length;
       used+=block_info.rec_len+info->s->pack.ref_length;
     }

isam/isamdef.h

@@ -358,6 +358,7 @@ extern int _nisam_read_pack_record(N_INFO *info,ulong filepos,byte *buf);
 extern int _nisam_read_rnd_pack_record(N_INFO*, byte *,ulong, int);
 extern int _nisam_pack_rec_unpack(N_INFO *info,byte *to,byte *from,
 			       uint reclength);
+extern ulong _nisam_checksum(const byte *mem, uint count);
 
 typedef struct st_sortinfo {
   uint key_length;

isam/open.c

@@ -453,3 +453,22 @@ static void setup_key_functions(register N_KEYDEF *keyinfo)
   }
   return;
 }
+
+/*
+  Calculate a long checksum for a memoryblock. Used to verify pack_isam
+
+  SYNOPSIS
+    checksum()
+      mem	Pointer to memory block
+      count	Count of bytes
+*/
+
+ulong _nisam_checksum(const byte *mem, uint count)
+{
+  ulong crc;
+  for (crc= 0; count-- ; mem++)
+    crc= ((crc << 1) + *((uchar*) mem)) +
+      test(crc & ((ulong) 1L << (8*sizeof(ulong)-1)));
+  return crc;
+}
+

isam/pack_isam.c

@@ -738,7 +738,7 @@ static int get_statistic(MRG_INFO *mrg,HUFF_COUNTS *huff_counts)
   {
     if (! error)
     {
-      crc^=checksum(record,reclength);
+      crc^=_nisam_checksum(record,reclength);
       for (pos=record,count=huff_counts ;
 	   count < end_count ;
 	   count++,

myisam/mi_checksum.c

@@ -28,30 +28,29 @@ ha_checksum mi_checksum(MI_INFO *info, const byte *buf)
   {
     const byte *pos;
     const byte *end;
+    ulong length;
     switch (rec->type) {
     case FIELD_BLOB:
     {
-      ulong length=_mi_calc_blob_length(rec->length-
+      length=_mi_calc_blob_length(rec->length-
 					mi_portable_sizeof_char_ptr,
 					buf);
       memcpy((char*) &pos, buf+rec->length- mi_portable_sizeof_char_ptr,
 	     sizeof(char*));
-      end=pos+length;
       break;
     }
     case FIELD_VARCHAR:
     {
-      uint length;
       length=uint2korr(buf);
-      pos=buf+2; end=pos+length;
+      pos=buf+2;
       break;
     }
     default:
-      pos=buf; end=buf+rec->length;
+      length=rec->length;
+      pos=buf;
       break;
     }
-    for ( ; pos != end ; pos++)
+    crc=my_checksum(crc, pos, length);
-      crc=((crc << 8) + *((uchar*) pos)) + (crc >> (8*sizeof(ha_checksum)-8));
   }
   return crc;
 }
@@ -59,9 +58,5 @@ ha_checksum mi_checksum(MI_INFO *info, const byte *buf)
 
 ha_checksum mi_static_checksum(MI_INFO *info, const byte *pos)
 {
-  ha_checksum crc;
+  return my_checksum(0, pos, info->s->base.reclength);
-  const byte *end=pos+info->s->base.reclength;
-  for (crc=0; pos != end; pos++)
-      crc=((crc << 8) + *((uchar*) pos)) + (crc >> (8*sizeof(ha_checksum)-8));
-  return crc;
 }

mysys/checksum.c

@@ -19,19 +19,20 @@
 #include "my_sys.h"
 
 /*
-  Calculate a long checksum for a memoryblock. Used to verify pack_isam 
+  Calculate a long checksum for a memoryblock.
 
   SYNOPSIS
-    checksum()
+    my_checksum()
-      mem	Pointer to memory block
+      crc       start value for crc
-      count	Count of bytes 
+      pos       pointer to memory block
+      length    length of the block
 */
 
-ulong checksum(const byte *mem, uint count)
+ha_checksum my_checksum(ha_checksum crc, const byte *pos, uint length)
 {
-  ulong crc;
+  const byte *end=pos+length;
-  for (crc= 0; count-- ; mem++)
+  for ( ; pos != end ; pos++)
-    crc= ((crc << 1) + *((uchar*) mem)) +
+    crc=((crc << 8) + *((uchar*) pos)) + (crc >> (8*sizeof(ha_checksum)-8));
-      test(crc & ((ulong) 1L << (8*sizeof(ulong)-1)));
   return crc;
 }
+

sql/ha_myisam.cc

@@ -236,6 +236,8 @@ int ha_myisam::open(const char *name, int mode, uint test_if_locked)
     VOID(mi_extra(file, HA_EXTRA_WAIT_LOCK, 0));
   if (!table->db_record_offset)
     int_table_flags|=HA_REC_NOT_IN_SEQ;
+  if (file->s->options & (HA_OPTION_CHECKSUM | HA_OPTION_COMPRESS_RECORD))
+    int_table_flags|=HA_HAS_CHECKSUM;
   return (0);
 }
 
@@ -1398,3 +1400,9 @@ int ha_myisam::ft_read(byte * buf)
   table->status=error ? STATUS_NOT_FOUND: 0;
   return error;
 }
+
+uint ha_myisam::checksum() const
+{
+  return (uint)file->s->state.checksum;
+}
+

sql/ha_myisam.h

@@ -64,6 +64,7 @@ class ha_myisam: public handler
   uint max_keys()          const { return MI_MAX_KEY; }
   uint max_key_parts()     const { return MAX_REF_PARTS; }
   uint max_key_length()    const { return MI_MAX_KEY_LENGTH; }
+  uint checksum() const;
 
   int open(const char *name, int mode, uint test_if_locked);
   int close(void);

sql/handler.h

@@ -42,38 +42,39 @@
 #define HA_ADMIN_INVALID         -5
 
 /* Bits in table_flags() to show what database can do */
-#define HA_READ_RND_SAME	1	/* Read RND-record to KEY-record
+#define HA_READ_RND_SAME        1       /* Read RND-record to KEY-record
-					   (To update with RND-read)	   */
+                                           (To update with RND-read)       */
-#define HA_KEYPOS_TO_RNDPOS	2	/* ha_info gives pos to record */
+#define HA_KEYPOS_TO_RNDPOS     2       /* ha_info gives pos to record */
-#define HA_TABLE_SCAN_ON_INDEX  4	/* No separate data/index file */
+#define HA_TABLE_SCAN_ON_INDEX  4       /* No separate data/index file */
-#define HA_REC_NOT_IN_SEQ	8	/* ha_info don't return recnumber;
+#define HA_REC_NOT_IN_SEQ       8       /* ha_info don't return recnumber;
-					   It returns a position to ha_r_rnd */
+                                           It returns a position to ha_r_rnd */
-#define HA_HAS_GEOMETRY 	16
+#define HA_HAS_GEOMETRY        (1 << 4)
-#define HA_NO_INDEX		32	/* No index needed for next/prev */
+#define HA_NO_INDEX            (1 << 5) /* No index needed for next/prev */
-#define HA_KEY_READ_WRONG_STR	64	/* keyread returns converted strings */
+#define HA_KEY_READ_WRONG_STR  (1 << 6) /* keyread returns converted strings */
-#define HA_NULL_KEY		128	/* One can have keys with NULL */
+#define HA_NULL_KEY            (1 << 7) /* One can have keys with NULL */
-#define HA_DUPP_POS		256	/* ha_position() gives dupp row */
+#define HA_DUPP_POS            (1 << 8) /* ha_position() gives dupp row */
-#define HA_NO_BLOBS		512	/* Doesn't support blobs */
+#define HA_NO_BLOBS            (1 << 9) /* Doesn't support blobs */
-#define HA_BLOB_KEY		(HA_NO_BLOBS*2) /* key on blob */
+#define HA_BLOB_KEY            (1 << 10) /* key on blob */
-#define HA_AUTO_PART_KEY	(HA_BLOB_KEY*2)
+#define HA_AUTO_PART_KEY       (1 << 11)
-#define HA_REQUIRE_PRIMARY_KEY	(HA_AUTO_PART_KEY*2)
+#define HA_REQUIRE_PRIMARY_KEY (1 << 12)
-#define HA_NOT_EXACT_COUNT	(HA_REQUIRE_PRIMARY_KEY*2)
+#define HA_NOT_EXACT_COUNT     (1 << 13)
-#define HA_NO_WRITE_DELAYED	(HA_NOT_EXACT_COUNT*2)
+#define HA_NO_WRITE_DELAYED    (1 << 14)
-#define HA_PRIMARY_KEY_IN_READ_INDEX (HA_NO_WRITE_DELAYED*2)
+#define HA_PRIMARY_KEY_IN_READ_INDEX (1 << 15)
-#define HA_DROP_BEFORE_CREATE	(HA_PRIMARY_KEY_IN_READ_INDEX*2)
+#define HA_DROP_BEFORE_CREATE  (1 << 16)
-#define HA_NOT_READ_AFTER_KEY	(HA_DROP_BEFORE_CREATE*2)
+#define HA_NOT_READ_AFTER_KEY  (1 << 17)
-#define HA_NOT_DELETE_WITH_CACHE (HA_NOT_READ_AFTER_KEY*2)
+#define HA_NOT_DELETE_WITH_CACHE (1 << 18)
-#define HA_NO_TEMP_TABLES       (HA_NOT_DELETE_WITH_CACHE*2)
+#define HA_NO_TEMP_TABLES      (1 << 19)
-#define HA_NO_PREFIX_CHAR_KEYS	(HA_NO_TEMP_TABLES*2) 
+#define HA_NO_PREFIX_CHAR_KEYS (1 << 20)
-#define HA_CAN_FULLTEXT         (HA_NO_PREFIX_CHAR_KEYS*2)
+#define HA_CAN_FULLTEXT        (1 << 21)
-#define HA_CAN_SQL_HANDLER      (HA_CAN_FULLTEXT*2)
+#define HA_CAN_SQL_HANDLER     (1 << 22)
-#define HA_NO_AUTO_INCREMENT	(HA_CAN_SQL_HANDLER*2)
+#define HA_NO_AUTO_INCREMENT   (1 << 23)
+#define HA_HAS_CHECKSUM        (1 << 24)
 
 /*
   Next record gives next record according last record read (even
   if database is updated after read).  Not used at this point.
 */
-#define HA_LASTKEY_ORDER	(HA_NO_AUTO_INCREMENT*2)
+#define HA_LASTKEY_ORDER	(1 << 25)
 
 
 /* bits in index_flags(index_number) for what you can do with index */
@@ -304,8 +305,8 @@ public:
   virtual bool check_and_repair(THD *thd) {return 1;}
   virtual int optimize(THD* thd,HA_CHECK_OPT* check_opt);
   virtual int analyze(THD* thd, HA_CHECK_OPT* check_opt);
-  virtual int backup(THD* thd, HA_CHECK_OPT* check_opt);
   virtual int preload_keys(THD* thd, HA_CHECK_OPT* check_opt);
+  virtual int backup(THD* thd, HA_CHECK_OPT* check_opt);
   /*
     restore assumes .frm file must exist, and that generate_table() has been
     called; It will just copy the data file and run repair.
@@ -340,6 +341,7 @@ public:
   virtual uint max_key_part_length() { return 255; }
   virtual uint min_record_length(uint options) const { return 1; }
   virtual bool low_byte_first() const { return 1; }
+  virtual uint checksum() const { return 0; }
   virtual bool is_crashed() const  { return 0; }
   virtual bool auto_repair() const { return 0; }
 
@@ -354,12 +356,11 @@ public:
   /* Type of table for caching query */
   virtual uint8 table_cache_type() { return HA_CACHE_TBL_NONTRANSACT; }
   /*
-    Is query with this cable cachable (have sense only for ASKTRANSACT 
+    Is query with this table cachable (have sense only for ASKTRANSACT
     tables)
   */
   static bool caching_allowed(THD* thd, char* table_key,
 			      uint key_length, uint8 cahe_type);
-
 };
 
 	/* Some extern variables used with handlers */

sql/sql_lex.h

@@ -447,15 +447,21 @@ typedef struct st_lex
   SELECT_LEX *all_selects_list;
   uchar *ptr,*tok_start,*tok_end,*end_of_query;
   char *length,*dec,*change,*name;
+  char *help_arg;
   char *backup_dir;				/* For RESTORE/BACKUP */
   char* to_log;                                 /* For PURGE MASTER LOGS TO */
   time_t purge_time;                            /* For PURGE MASTER LOGS BEFORE */
   char* x509_subject,*x509_issuer,*ssl_cipher;
   char* found_colon;                            /* For multi queries - next query */
-  enum SSL_type ssl_type;			/* defined in violite.h */
   String *wild;
   sql_exchange *exchange;
   select_result *result;
+  Item *default_value, *comment;
+  LEX_USER *grant_user;
+  gptr yacc_yyss,yacc_yyvs;
+  THD *thd;
+  CHARSET_INFO *charset;
+  SQL_LIST *gorder_list;
 
   List<key_part_spec> col_list;
   List<key_part_spec> ref_list;
@@ -473,11 +479,6 @@ typedef struct st_lex
   SQL_LIST	      proc_list, auxilliary_table_list;
   TYPELIB	      *interval;
   create_field	      *last_field;
-  Item *default_value, *comment;
-  uint uint_geom_type;
-  LEX_USER *grant_user;
-  gptr yacc_yyss,yacc_yyvs;
-  THD *thd;
   udf_func udf;
   HA_CHECK_OPT   check_opt;			// check/repair options
   HA_CREATE_INFO create_info;
@@ -486,6 +487,7 @@ typedef struct st_lex
   ulong thread_id,type;
   enum_sql_command sql_command;
   thr_lock_type lock_option;
+  enum SSL_type ssl_type;			/* defined in violite.h */
   enum my_lex_states next_state;
   enum enum_duplicates duplicates;
   enum enum_tx_isolation tx_isolation;
@@ -493,17 +495,15 @@ typedef struct st_lex
   enum ha_rkey_function ha_rkey_mode;
   enum enum_enable_or_disable alter_keys_onoff;
   enum enum_var_type option_type;
+  uint uint_geom_type;
   uint grant, grant_tot_col, which_columns;
   uint fk_delete_opt, fk_update_opt, fk_match_option;
   uint param_count;
+  uint slave_thd_opt;
   bool drop_primary, drop_if_exists, drop_temporary, local_file;
   bool in_comment, ignore_space, verbose, simple_alter, no_write_to_binlog;
   bool derived_tables, describe;
   bool safe_to_cache_query;
-  uint slave_thd_opt;
-  CHARSET_INFO *charset;
-  char *help_arg;
-  SQL_LIST *gorder_list;
   st_lex() {}
   inline void uncacheable()
   {

sql/sql_select.cc

@@ -2349,7 +2349,7 @@ static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array)
       Constant tables are ignored.
       To avoid bad matches, we don't make ref_table_rows less than 100.
     */
-    keyuse->ref_table_rows= ~(table_map) 0;	// If no ref
+    keyuse->ref_table_rows= ~(ha_rows) 0;	// If no ref
     if (keyuse->used_tables &
 	(map= (keyuse->used_tables & ~join->const_table_map &
 	       ~OUTER_REF_TABLE_BIT)))

sql/sql_show.cc

@@ -503,6 +503,8 @@ int mysqld_extend_show_tables(THD *thd,const char *db,const char *wild)
   item->maybe_null=1;
   field_list.push_back(item=new Item_empty_string("Charset",32));
   item->maybe_null=1;
+  field_list.push_back(item=new Item_int("Checksum",(longlong) 1,21));
+  item->maybe_null=1;
   field_list.push_back(item=new Item_empty_string("Create_options",255));
   item->maybe_null=1;
   field_list.push_back(item=new Item_empty_string("Comment",80));
@@ -588,6 +590,10 @@ int mysqld_extend_show_tables(THD *thd,const char *db,const char *wild)
       }
       str= (table->table_charset ? table->table_charset->name : "default");
       protocol->store(str, system_charset_info);
+      if (file->table_flags() & HA_HAS_CHECKSUM)
+        protocol->store((ulonglong)file->checksum());
+      else
+        protocol->store_null(); // Checksum
       {
         char option_buff[350],*ptr;
         ptr=option_buff;

sql/sql_yacc.yy

@@ -730,17 +730,19 @@ verb_clause:
 	| describe
 	| do
 	| drop
-	| grant
-	| insert
 	| flush
+	| grant
+	| handler
+	| help
+	| insert
+	| kill
 	| load
 	| lock
-	| kill
 	| optimize
 	| preload
 	| purge
 	| rename
-        | repair
+	| repair
 	| replace
 	| reset
 	| restore
@@ -748,15 +750,14 @@ verb_clause:
 	| rollback
 	| select
 	| set
+	| show
 	| slave
 	| start
-	| show
 	| truncate
-	| handler
 	| unlock
 	| update
 	| use
-	| help;
+        ;
 
 /* help */
 
@@ -3327,7 +3328,7 @@ do:	DO_SYM
 */
 
 drop:
-	DROP opt_temporary TABLE_SYM if_exists table_list opt_restrict
+	DROP opt_temporary table_or_tables if_exists table_list opt_restrict
 	{
 	  LEX *lex=Lex;
 	  lex->sql_command = SQLCOM_DROP_TABLE;
@@ -4851,7 +4852,7 @@ grant_privilege_list:
 	| grant_privilege_list ',' grant_privilege;
 
 grant_privilege:
-	SELECT_SYM 	{ Lex->which_columns = SELECT_ACL;} opt_column_list {}
+	SELECT_SYM	{ Lex->which_columns = SELECT_ACL;} opt_column_list {}
 	| INSERT	{ Lex->which_columns = INSERT_ACL;} opt_column_list {}
 	| UPDATE_SYM	{ Lex->which_columns = UPDATE_ACL; } opt_column_list {}
 	| REFERENCES	{ Lex->which_columns = REFERENCES_ACL;} opt_column_list {}
@@ -5228,3 +5229,4 @@ subselect_end:
 	  LEX *lex=Lex;
 	  lex->current_select = lex->current_select->return_after_parsing();
 	};
+