Proposed fix for Bug#4026 "Microseconds part of TIME/DATETIME types

is broken (prepared statements)": fixed date handling in many places 
of prepared statements code.


libmysql/libmysql.c:
  Fix for Bug#4026:
  - now buffer_length is defined for any buffer type. Network buffer 
    preallocation cleaned up.
  - added constants for maximum buffer sizes necessary for MYSQL_TYPE_DATE,
    MYSQL_TYPE_TIME, MYSQL_TYPE_DATETIME types.
  - TIME/DATETIME packing/unpacking functions fixed 
  - now result set metadata is always updated from fields sent to COM_EXECUTE.
    This is necessary to make 'SELECT ?' queries work without conversions.
sql/item.cc:
  - added implementatoin of Item_param::get_date
sql/item.h:
  - added enum_field_types Item_param::param_type. First step for proper
    handling of placeholders.
  - added get_date() implementation to prevent date -> string -> date 
    conversions when MYSQL_TYPE_DATE/DATETIME parameter is used in temporal 
    context.
sql/protocol.cc:
  Fix for Bug#4026:
  - PACKET_BUFFET_EXTRA_ALLOC -> PACKET_BUFFER_EXTRA_ALLOC.
    The define itself was moved to .cc as it's used only in protocol.cc
  - fixed Protocol_prep::store_time() call.
sql/protocol.h:
  - PACKET_BUFFER_EXTRA_ALLOC moved to protocol.cc
sql/sql_prepare.cc:
  Fix for Bug#4026:
  - MYSQL_TYPE_TIME/DATETIME handling fixed.
  - added initialization for Item_param::param_type in 
    setup_one_conversion_function
tests/client_test.c:
  Test case for Bug#4026

libmysql/libmysql.c

@@ -1667,6 +1667,27 @@ static int stmt_read_row_buffered(MYSQL_STMT *stmt, unsigned char **row);
 static int stmt_read_row_no_data(MYSQL_STMT *stmt, unsigned char **row);
 
 
+/*
+  Maximum sizes of MYSQL_TYPE_DATE, MYSQL_TYPE_TIME, MYSQL_TYPE_DATETIME
+  values stored in network buffer.
+*/
+
+/* 1 (length) + 2 (year) + 1 (month) + 1 (day) */
+static const unsigned MAX_DATE_REP_LENGTH= 5;
+
+/*
+  1 (length) + 1 (is negative) + 4 (day count) + 1 (hour)
+  + 1 (minute) + 1 (seconds) + 4 (microseconds)
+*/
+static const unsigned MAX_TIME_REP_LENGTH= 13;
+
+/*
+  1 (length) + 2 (year) + 1 (month) + 1 (day) +
+  1 (hour) + 1 (minute) + 1 (second) + 4 (microseconds)
+*/
+static const unsigned MAX_DATETIME_REP_LENGTH= 12;
+
+
 /**************** Misc utility functions ****************************/
 
 /*
@@ -2030,6 +2051,30 @@ static unsigned int alloc_stmt_fields(MYSQL_STMT *stmt)
   return stmt->field_count;
 }
 
+
+/*
+  Update result set columns metadata if it was sent again in
+  reply to COM_EXECUTE.
+*/
+
+static void update_stmt_fields(MYSQL_STMT *stmt)
+{
+  MYSQL_FIELD *field= stmt->mysql->fields;
+  MYSQL_FIELD *field_end= field + stmt->field_count;
+  MYSQL_FIELD *stmt_field= stmt->fields;
+
+  DBUG_ASSERT(stmt->field_count == stmt->mysql->field_count);
+
+  for (; field < field_end; ++field, ++stmt_field)
+  {
+    stmt_field->charsetnr= field->charsetnr;
+    stmt_field->length   = field->length;
+    stmt_field->type     = field->type;
+    stmt_field->flags    = field->flags;
+    stmt_field->decimals = field->decimals;
+  }
+}
+
 /*
   Returns prepared statement metadata in the form of a result set.
 
@@ -2166,7 +2211,7 @@ static void store_param_double(NET *net, MYSQL_BIND *param)
 static void store_param_time(NET *net, MYSQL_BIND *param)
 {
   MYSQL_TIME *tm= (MYSQL_TIME *) param->buffer;
-  char buff[15], *pos;
+  char buff[MAX_TIME_REP_LENGTH], *pos;
   uint length;
 
   pos= buff+1;
@@ -2177,19 +2222,19 @@ static void store_param_time(NET *net, MYSQL_BIND *param)
   pos[7]= (uchar) tm->second;
   int4store(pos+8, tm->second_part);
   if (tm->second_part)
-    length= 11;
+    length= 12;
   else if (tm->hour || tm->minute || tm->second || tm->day)
     length= 8;
   else
     length= 0;
-  buff[0]= (char) length++;  
+  buff[0]= (char) length++;
   memcpy((char *)net->write_pos, buff, length);
   net->write_pos+= length;
 }
 
 static void net_store_datetime(NET *net, MYSQL_TIME *tm)
 {
-  char buff[12], *pos;
+  char buff[MAX_DATETIME_REP_LENGTH], *pos;
   uint length;
 
   pos= buff+1;
@@ -2280,7 +2325,7 @@ static my_bool store_param(MYSQL_STMT *stmt, MYSQL_BIND *param)
       Param->length should ALWAYS point to the correct length for the type
       Either to the length pointer given by the user or param->buffer_length
     */
-    if ((my_realloc_str(net, 9 + *param->length)))
+    if ((my_realloc_str(net, *param->length)))
     {
       set_stmt_error(stmt, CR_OUT_OF_MEMORY, unknown_sqlstate);
       DBUG_RETURN(1);
@@ -2557,16 +2602,37 @@ int STDCALL mysql_stmt_execute(MYSQL_STMT *stmt)
   */
   if (mysql->methods->stmt_execute(stmt))
     DBUG_RETURN(1);
-  if (!stmt->field_count && mysql->field_count)
+  if (mysql->field_count)
   {
-    /* 
-      This is 'SHOW'/'EXPLAIN'-like query.  Current implementation of
-      prepared statements can't send result set metadata for this queries
-      on prepare stage. Read it now.
-    */
-    alloc_stmt_fields(stmt);
+    /* Server has sent result set metadata */
+    if (stmt->field_count == 0)
+    {
+      /*
+        This is 'SHOW'/'EXPLAIN'-like query. Current implementation of
+        prepared statements can't send result set metadata for these queries
+        on prepare stage. Read it now.
+      */
+      alloc_stmt_fields(stmt);
+    }
+    else
+    {
+      /*
+        Update result set metadata if it for some reason changed between
+        prepare and execute, i.e.:
+        - in case of 'SELECT ?' we don't know column type unless data was
+          supplied to mysql_stmt_execute, so updated column type is sent
+          now.
+        - if data dictionary changed between prepare and execute, for
+          example a table used in the query was altered.
+        Note, that now (4.1.3) we always send metadata in reply to
+        COM_EXECUTE (even if it is not necessary), so either this or
+        previous always branch works.
+        TODO: send metadata only when it's really necessary and add a warning
+        'Metadata changed' when it's sent twice.
+      */
+      update_stmt_fields(stmt);
+    }
   }
-      
   stmt->state= MYSQL_STMT_EXECUTE_DONE;
   if (stmt->field_count)
   {
@@ -2693,15 +2759,17 @@ my_bool STDCALL mysql_stmt_bind_param(MYSQL_STMT *stmt, MYSQL_BIND * bind)
       param->store_param_func= store_param_double;
       break;
     case MYSQL_TYPE_TIME:
-      /* Buffer length ignored for DATE, TIME and DATETIME */
       param->store_param_func= store_param_time;
+      param->buffer_length= MAX_TIME_REP_LENGTH;
       break;
     case MYSQL_TYPE_DATE:
       param->store_param_func= store_param_date;
+      param->buffer_length= MAX_DATE_REP_LENGTH;
       break;
     case MYSQL_TYPE_DATETIME:
     case MYSQL_TYPE_TIMESTAMP:
       param->store_param_func= store_param_datetime;
+      param->buffer_length= MAX_DATETIME_REP_LENGTH;
       break;
     case MYSQL_TYPE_TINY_BLOB:
     case MYSQL_TYPE_MEDIUM_BLOB:
@@ -2859,17 +2927,17 @@ static uint read_binary_time(MYSQL_TIME *tm, uchar **pos)
     set_zero_time(tm);
     return 0;
   }
-  
-  to= *pos;     
-  tm->second_part= (length > 8 ) ? (ulong) sint4korr(to+7): 0;
+
+  to= *pos;
+  tm->neg= (bool) to[0];
 
   tm->day=    (ulong) sint4korr(to+1);
   tm->hour=   (uint) to[5];
   tm->minute= (uint) to[6];
   tm->second= (uint) to[7];
+  tm->second_part= (length > 8) ? (ulong) sint4korr(to+8) : 0;
 
   tm->year= tm->month= 0;
-  tm->neg= (bool)to[0];
   return length;
 }
 
@@ -2878,16 +2946,20 @@ static uint read_binary_datetime(MYSQL_TIME *tm, uchar **pos)
 {
   uchar *to;
   uint  length;
- 
+
   if (!(length= net_field_length(pos)))
   {
     set_zero_time(tm);
     return 0;
   }
-  
-  to= *pos;     
-  tm->second_part= (length > 7 ) ? (ulong) sint4korr(to+7): 0;
-    
+
+  to= *pos;
+
+  tm->neg=    0;
+  tm->year=   (uint) sint2korr(to);
+  tm->month=  (uint) to[2];
+  tm->day=    (uint) to[3];
+
   if (length > 4)
   {
     tm->hour=   (uint) to[4];
@@ -2896,11 +2968,7 @@ static uint read_binary_datetime(MYSQL_TIME *tm, uchar **pos)
   }
   else
     tm->hour= tm->minute= tm->second= 0;
-    
-  tm->year=   (uint) sint2korr(to);
-  tm->month=  (uint) to[2];
-  tm->day=    (uint) to[3];
-  tm->neg=    0;
+  tm->second_part= (length > 7) ? (ulong) sint4korr(to+7) : 0;
   return length;
 }
 
@@ -3159,7 +3227,7 @@ static void send_data_time(MYSQL_BIND *param, MYSQL_TIME ltime,
   }
   }
 }
-                              
+
 
 /* Fetch data to buffers */
 

sql/item.cc

@@ -629,6 +629,7 @@ Item_param::Item_param(unsigned pos_in_query_arg) :
   state(NO_VALUE),
   item_result_type(STRING_RESULT),
   item_type(STRING_ITEM),
+  param_type(MYSQL_TYPE_STRING),
   pos_in_query(pos_in_query_arg),
   set_param_func(default_set_param_func)
 {
@@ -808,6 +809,17 @@ bool Item_param::get_time(TIME *res)
 }
 
 
+bool Item_param::get_date(TIME *res, uint fuzzydate)
+{
+  if (state == TIME_VALUE)
+  {
+    *res= value.time;
+    return 0;
+  }
+  return Item::get_date(res, fuzzydate);
+}
+
+
 double Item_param::val() 
 {
   switch (state) {

sql/item.h

@@ -465,6 +465,16 @@ class Item_param :public Item
   /* Cached values for virtual methods to save us one switch.  */
   enum Item_result item_result_type;
   enum Type item_type;
+
+  /*
+    Used when this item is used in a temporary table.
+    This is NOT placeholder metadata sent to client, as this value
+    is assigned after sending metadata (in setup_one_conversion_function).
+    For example in case of 'SELECT ?' you'll get MYSQL_TYPE_STRING both
+    in result set and placeholders metadata, no matter what type you will
+    supply for this placeholder in mysql_stmt_execute.
+  */
+  enum enum_field_types param_type;
   /*         
     Offset of placeholder inside statement text. Used to create
     no-placeholders version of this statement for the binary log.
@@ -475,12 +485,13 @@ class Item_param :public Item
 
   enum Item_result result_type () const { return item_result_type; }
   enum Type type() const { return item_type; }
-  enum_field_types field_type() const { return MYSQL_TYPE_STRING; }
+  enum_field_types field_type() const { return param_type; }
 
   double val();
   longlong val_int();
   String *val_str(String*);
   bool get_time(TIME *tm);
+  bool get_date(TIME *tm, uint fuzzydate);
   int  save_in_field(Field *field, bool no_conversions);
 
   void set_null();

sql/protocol.cc

@@ -26,6 +26,8 @@
 #include "mysql_priv.h"
 #include <stdarg.h>
 
+static const unsigned int PACKET_BUFFER_EXTRA_ALLOC= 1024;
+
 #ifndef EMBEDDED_LIBRARY
 bool Protocol::net_store_data(const char *from, uint length)
 #else
@@ -687,7 +689,7 @@ bool Protocol_simple::store_null()
 #endif
   char buff[1];
   buff[0]= (char)251;
-  return packet->append(buff, sizeof(buff), PACKET_BUFFET_EXTRA_ALLOC);
+  return packet->append(buff, sizeof(buff), PACKET_BUFFER_EXTRA_ALLOC);
 }
 #endif
 
@@ -990,7 +992,7 @@ bool Protocol_prep::store_tiny(longlong from)
   char buff[1];
   field_pos++;
   buff[0]= (uchar) from;
-  return packet->append(buff, sizeof(buff), PACKET_BUFFET_EXTRA_ALLOC);
+  return packet->append(buff, sizeof(buff), PACKET_BUFFER_EXTRA_ALLOC);
 }
 
 
@@ -1002,7 +1004,7 @@ bool Protocol_prep::store_short(longlong from)
         field_types[field_pos] == MYSQL_TYPE_YEAR);
 #endif
   field_pos++;
-  char *to= packet->prep_append(2, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(2, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   int2store(to, (int) from);
@@ -1018,7 +1020,7 @@ bool Protocol_prep::store_long(longlong from)
 	      field_types[field_pos] == MYSQL_TYPE_LONG);
 #endif
   field_pos++;
-  char *to= packet->prep_append(4, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(4, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   int4store(to, from);
@@ -1033,7 +1035,7 @@ bool Protocol_prep::store_longlong(longlong from, bool unsigned_flag)
 	      field_types[field_pos] == MYSQL_TYPE_LONGLONG);
 #endif
   field_pos++;
-  char *to= packet->prep_append(8, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(8, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   int8store(to, from);
@@ -1048,7 +1050,7 @@ bool Protocol_prep::store(float from, uint32 decimals, String *buffer)
 	      field_types[field_pos] == MYSQL_TYPE_FLOAT);
 #endif
   field_pos++;
-  char *to= packet->prep_append(4, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(4, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   float4store(to, from);
@@ -1063,7 +1065,7 @@ bool Protocol_prep::store(double from, uint32 decimals, String *buffer)
 	      field_types[field_pos] == MYSQL_TYPE_DOUBLE);
 #endif
   field_pos++;
-  char *to= packet->prep_append(8, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(8, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   float8store(to, from);
@@ -1112,7 +1114,7 @@ bool Protocol_prep::store(TIME *tm)
   else
     length=0;
   buff[0]=(char) length;			// Length is stored first
-  return packet->append(buff, length+1, PACKET_BUFFET_EXTRA_ALLOC);
+  return packet->append(buff, length+1, PACKET_BUFFER_EXTRA_ALLOC);
 }
 
 bool Protocol_prep::store_date(TIME *tm)
@@ -1129,7 +1131,7 @@ bool Protocol_prep::store_time(TIME *tm)
   DBUG_ASSERT(field_types == 0 ||
 	      field_types[field_pos] == MYSQL_TYPE_TIME);
 #endif
-  char buff[15],*pos;
+  char buff[13], *pos;
   uint length;
   field_pos++;
   pos= buff+1;
@@ -1140,13 +1142,13 @@ bool Protocol_prep::store_time(TIME *tm)
   pos[7]= (uchar) tm->second;
   int4store(pos+8, tm->second_part);
   if (tm->second_part)
-    length=11;
+    length=12;
   else if (tm->hour || tm->minute || tm->second || tm->day)
     length=8;
   else
     length=0;
   buff[0]=(char) length;			// Length is stored first
-  return packet->append(buff, length+1, PACKET_BUFFET_EXTRA_ALLOC);
+  return packet->append(buff, length+1, PACKET_BUFFER_EXTRA_ALLOC);
 }
 
 #ifdef EMBEDDED_LIBRARY

sql/protocol.h

@@ -18,7 +18,6 @@
 #pragma interface			/* gcc class implementation */
 #endif
 
-#define PACKET_BUFFET_EXTRA_ALLOC	1024
 
 class i_string;
 class THD;

sql/sql_prepare.cc

@@ -332,20 +332,19 @@ static void set_param_time(Item_param *param, uchar **pos, ulong len)
   {
     uchar *to= *pos;
     TIME  tm;
-    
-    /* TODO: why length is compared with 8 here? */
-    tm.second_part= (length > 8 ) ? (ulong) sint4korr(to+7): 0;
 
+    tm.neg= (bool) to[0];
+    day= (uint) sint4korr(to+1);
     /*
       Note, that though ranges of hour, minute and second are not checked
       here we rely on them being < 256: otherwise
       we'll get buffer overflow in make_{date,time} functions,
       which are called when time value is converted to string.
     */
-    day= (uint) sint4korr(to+1);
     tm.hour=   (uint) to[5] + day * 24;
     tm.minute= (uint) to[6];
     tm.second= (uint) to[7];
+    tm.second_part= (length > 8) ? (ulong) sint4korr(to+8) : 0;
     if (tm.hour > 838)
     {
       /* TODO: add warning 'Data truncated' here */
@@ -354,7 +353,6 @@ static void set_param_time(Item_param *param, uchar **pos, ulong len)
       tm.second= 59;
     }
     tm.day= tm.year= tm.month= 0;
-    tm.neg= (bool)to[0];
 
     param->set_time(&tm, TIMESTAMP_TIME,
                     MAX_TIME_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
@@ -365,14 +363,16 @@ static void set_param_time(Item_param *param, uchar **pos, ulong len)
 static void set_param_datetime(Item_param *param, uchar **pos, ulong len)
 {
   uint length;
- 
+
   if ((length= get_param_length(pos, len)) >= 4)
   {
     uchar *to= *pos;
     TIME  tm;
-    
-    tm.second_part= (length > 7 ) ? (ulong) sint4korr(to+7): 0;
-    
+
+    tm.neg=    0;
+    tm.year=   (uint) sint2korr(to);
+    tm.month=  (uint) to[2];
+    tm.day=    (uint) to[3];
     /*
       Note, that though ranges of hour, minute and second are not checked
       here we rely on them being < 256: otherwise
@@ -386,11 +386,8 @@ static void set_param_datetime(Item_param *param, uchar **pos, ulong len)
     }
     else
       tm.hour= tm.minute= tm.second= 0;
-    
-    tm.year=   (uint) sint2korr(to);
-    tm.month=  (uint) to[2];
-    tm.day=    (uint) to[3];
-    tm.neg=    0;
+
+    tm.second_part= (length > 7) ? (ulong) sint4korr(to+7) : 0;
 
     param->set_time(&tm, TIMESTAMP_DATETIME, 
                     MAX_DATETIME_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
@@ -585,6 +582,7 @@ static void setup_one_conversion_function(THD *thd, Item_param *param,
       param->item_result_type= STRING_RESULT;
     }
   }
+  param->param_type= (enum enum_field_types) param_type;
 }
 
 #ifndef EMBEDDED_LIBRARY

tests/client_test.c

@@ -9802,6 +9802,73 @@ static void test_bug3796()
   myquery(rc);
 }
 
+
+static void test_bug4026()
+{
+  MYSQL_STMT *stmt;
+  MYSQL_BIND bind[2];
+  MYSQL_TIME time_in, time_out;
+  MYSQL_TIME datetime_in, datetime_out;
+  const char *stmt_text;
+  int rc;
+
+  myheader("test_bug4026");
+
+  /* Check that microseconds are inserted and selected successfully */
+
+  /* Create a statement handle and prepare it with select */
+  stmt= mysql_stmt_init(mysql);
+  stmt_text= "SELECT ?, ?";
+
+  rc= mysql_stmt_prepare(stmt, stmt_text, strlen(stmt_text));
+  check_execute(stmt, rc);
+
+  /* Bind input buffers */
+  bzero(bind, sizeof(bind));
+  bzero(&time_in, sizeof(time_in));
+  bzero(&time_out, sizeof(time_out));
+  bzero(&datetime_in, sizeof(datetime_in));
+  bzero(&datetime_out, sizeof(datetime_out));
+
+  bind[0].buffer_type= MYSQL_TYPE_TIME;
+  bind[0].buffer= (char*) &time_in;
+  bind[1].buffer_type= MYSQL_TYPE_DATETIME;
+  bind[1].buffer= (char*) &datetime_in;
+
+  time_in.hour= 23;
+  time_in.minute= 59;
+  time_in.second= 59;
+  time_in.second_part= 123456;
+
+  datetime_in= time_in;
+  datetime_in.year= 2003;
+  datetime_in.month= 12;
+  datetime_in.day= 31;
+
+  mysql_stmt_bind_param(stmt, bind);
+
+  /* Execute the select statement */
+  rc= mysql_stmt_execute(stmt);
+  check_execute(stmt, rc);
+
+  bind[0].buffer= (char*) &time_out;
+  bind[1].buffer= (char*) &datetime_out;
+
+  mysql_stmt_bind_result(stmt, bind);
+
+  rc= mysql_stmt_fetch(stmt);
+  assert(rc == 0);
+  printf("%d:%d:%d.%lu\n", time_out.hour, time_out.minute, time_out.second,
+                           time_out.second_part);
+  printf("%d-%d-%d %d:%d:%d.%lu\n", datetime_out.year, datetime_out.month,
+                                    datetime_out.day, datetime_out.hour,
+                                    datetime_out.minute, datetime_out.second,
+                                    datetime_out.second_part);
+  assert(memcmp(&time_in, &time_out, sizeof(time_in)) == 0);
+  assert(memcmp(&datetime_in, &datetime_out, sizeof(datetime_in)) == 0);
+  mysql_stmt_close(stmt);
+}
+
 /*
   Read and parse arguments and MySQL options from my.cnf
 */
@@ -10094,6 +10161,7 @@ int main(int argc, char **argv)
                                (Bug #3686 */
     test_ps_i18n();         /* test for i18n support in binary protocol */
     test_bug3796();         /* test for select concat(?, <string>) */
+    test_bug4026();         /* test microseconds precision of time types */
     /*
       XXX: PLEASE RUN THIS PROGRAM UNDER VALGRIND AND VERIFY THAT YOUR TEST
       DOESN'T CONTAIN WARNINGS/ERRORS BEFORE YOU PUSH.