Style: partitioning, sysvars, handler fixes

* Sys_var_vers_asof formatting
* Vers_field_stats renamed to Vers_min_max_stats
* Item_temporal_literal::set_lower()/set_higher() replaced by operator>()/operator<()
* handler API comments

sql/handler.h

@@ -1392,9 +1392,41 @@ struct handlerton
    /*
      System Versioning
    */
+  /**
+    Query VTQ by TRX_ID.
+    @param[in]   thd       MySQL thread
+    @param[out]  out       field value or whole record returned by query (selected by `field`)
+    @param[in]   in_trx_id query parameter TRX_ID
+    @param[in]   field     field to get in `out` or VTQ_ALL for whole record (vtq_record_t)
+    @return                TRUE if record is found, FALSE otherwise */
    bool (*vers_query_trx_id)(THD* thd, void *out, ulonglong trx_id, vtq_field_t field);
-   bool (*vers_query_commit_ts)(THD* thd, void *out, const MYSQL_TIME &commit_ts, vtq_field_t field, bool backwards);
-   bool (*vers_trx_sees)(THD *thd, bool &result, ulonglong trx_id1, ulonglong trx_id0, ulonglong commit_id1, uchar iso_level1, ulonglong commit_id0);
+
+   /** Query VTQ by COMMIT_TS.
+    @param[in]    thd       MySQL thread
+    @param[out]   out       field value or whole record returned by query (selected by `field`)
+    @param[in]    commit_ts query parameter COMMIT_TS
+    @param[in]    field     field to get in `out` or VTQ_ALL for whole record (vtq_record_t)
+    @param[in]    backwards direction of VTQ search
+    @return                 TRUE if record is found, FALSE otherwise */
+   bool (*vers_query_commit_ts)(THD* thd, void *out, const MYSQL_TIME &commit_ts,
+                                vtq_field_t field, bool backwards);
+
+  /** Check if transaction TX1 sees transaction TX0.
+    @param[in]    thd         MySQL thread
+    @param[out]   result      true if TX1 sees TX0
+    @param[in]    trx_id1     TX1 TRX_ID
+    @param[in]    trx_id0     TX0 TRX_ID
+    @param[in]    commit_id1  TX1 COMMIT_ID
+    @param[in]    iso_level1  TX1 isolation level
+    @param[in]    commit_id0  TX0 COMMIT_ID
+    @return                   FALSE if there is no trx_id1 in VTQ, otherwise TRUE */
+   bool (*vers_trx_sees)(THD *thd, bool &result, ulonglong trx_id1, ulonglong trx_id0,
+                         ulonglong commit_id1, uchar iso_level1, ulonglong commit_id0);
+
+  /** Upgrade InnoDB table handler to InnoDB partitioning handler.
+    @param[in]    hnd         InnoDB table handler
+    @param[in]    mem_root    mem_root for resulting handler
+    @return                   InnoDB partitioning handler or NULL on error */
    handler *(*vers_upgrade_handler)(handler *hnd, MEM_ROOT *mem_root);
 };
 

sql/item.cc

@@ -6983,26 +6983,26 @@ bool Item_temporal_literal::eq(const Item *item, bool binary_cmp) const
                      &((Item_temporal_literal *) item)->cached_time);
 }
 
-bool Item_temporal_literal::set_lower(MYSQL_TIME * ltime)
+bool Item_temporal_literal::operator<(const MYSQL_TIME &ltime) const
 {
-  if (my_time_compare(ltime, &cached_time) < 0)
-  {
-    cached_time= *ltime;
+  if (my_time_compare(&cached_time, &ltime) < 0)
     return true;
-  }
   return false;
 }
 
-bool Item_temporal_literal::set_higher(MYSQL_TIME * ltime)
+bool Item_temporal_literal::operator>(const MYSQL_TIME &ltime) const
 {
-  if (my_time_compare(ltime, &cached_time) > 0)
-  {
-    cached_time= *ltime;
+  if (my_time_compare(&cached_time, &ltime) > 0)
     return true;
-  }
   return false;
 }
 
+bool Item_temporal_literal::operator==(const MYSQL_TIME &ltime) const
+{
+  if (my_time_compare(&cached_time, &ltime) == 0)
+    return true;
+  return false;
+}
 
 void Item_date_literal::print(String *str, enum_query_type query_type)
 {

sql/item.h

@@ -3878,8 +3878,9 @@ class Item_temporal_literal :public Item_basic_constant
   {
     cached_time= *ltime;
   }
-  bool set_lower(MYSQL_TIME *ltime);
-  bool set_higher(MYSQL_TIME *ltime);
+  bool operator>(const MYSQL_TIME &ltime) const;
+  bool operator<(const MYSQL_TIME &ltime) const;
+  bool operator==(const MYSQL_TIME &ltime) const;
 };
 
 

sql/partition_element.h

@@ -90,7 +90,9 @@ typedef struct p_elem_val
 
 struct st_ddl_log_memory_entry;
 
-class Vers_field_stats : public Sql_alloc
+/* Used for collecting MIN/MAX stats on sys_trx_end for doing pruning
+   in SYSTEM_TIME partitiong. */
+class Vers_min_max_stats : public Sql_alloc
 {
   static const uint buf_size= 4 + (TIME_SECOND_PART_DIGITS + 1) / 2;
   uchar min_buf[buf_size];
@@ -100,7 +102,7 @@ class Vers_field_stats : public Sql_alloc
   mysql_rwlock_t lock;
 
 public:
-  Vers_field_stats(const char *field_name, TABLE_SHARE *share) :
+  Vers_min_max_stats(const char *field_name, TABLE_SHARE *share) :
     min_value(min_buf, NULL, 0, Field::NONE, field_name, share, 6),
     max_value(max_buf, NULL, 0, Field::NONE, field_name, share, 6)
   {
@@ -108,7 +110,7 @@ class Vers_field_stats : public Sql_alloc
     memset(max_buf, 0, buf_size);
     mysql_rwlock_init(key_rwlock_LOCK_vers_stats, &lock);
   }
-  ~Vers_field_stats()
+  ~Vers_min_max_stats()
   {
     mysql_rwlock_destroy(&lock);
   }

sql/partition_info.cc

@@ -926,8 +926,8 @@ bool partition_info::vers_setup_1(THD * thd, uint32 added)
   if (added)
   {
     DBUG_ASSERT(partitions.elements > added + 1);
-    Vers_field_stats** old_array= table->s->stat_trx;
-    table->s->stat_trx= static_cast<Vers_field_stats**>(
+    Vers_min_max_stats** old_array= table->s->stat_trx;
+    table->s->stat_trx= static_cast<Vers_min_max_stats**>(
       alloc_root(&table->s->mem_root, sizeof(void *) * partitions.elements * num_columns));
     memcpy(table->s->stat_trx, old_array, sizeof(void *) * (partitions.elements - added) * num_columns);
   }
@@ -961,8 +961,8 @@ bool partition_info::vers_setup_1(THD * thd, uint32 added)
       if (el->id == UINT32_MAX || el->type == partition_element::AS_OF_NOW)
       {
         DBUG_ASSERT(table && table->s);
-        Vers_field_stats *stat_trx_end= new (&table->s->mem_root)
-          Vers_field_stats(table->s->vers_end_field()->field_name, table->s);
+        Vers_min_max_stats *stat_trx_end= new (&table->s->mem_root)
+          Vers_min_max_stats(table->s->vers_end_field()->field_name, table->s);
         table->s->stat_trx[id * num_columns + STAT_TRX_END]= stat_trx_end;
         el->id= id++;
         if (el->type == partition_element::AS_OF_NOW)
@@ -1107,7 +1107,7 @@ void partition_info::vers_update_col_vals(THD *thd, partition_element *el0, part
   my_time_t ts;
   part_column_list_val *col_val;
   Item_datetime_literal *val_item;
-  Vers_field_stats *stat_trx_x;
+  Vers_min_max_stats *stat_trx_x;
   for (uint i= 0; i < num_columns; ++i)
   {
     stat_trx_x= table->s->stat_trx[idx + i];
@@ -1118,9 +1118,12 @@ void partition_info::vers_update_col_vals(THD *thd, partition_element *el0, part
       col_val= &el0->get_col_val(i);
       val_item= static_cast<Item_datetime_literal*>(col_val->item_expression);
       DBUG_ASSERT(val_item);
-      if (val_item->set_lower(&t))
+      if (*val_item > t)
+      {
+        val_item->set_time(&t);
         col_val->fixed= 0;
       }
+    }
     col_val= &el1->get_col_val(i);
     if (!col_val->max_value)
     {
@@ -1128,10 +1131,13 @@ void partition_info::vers_update_col_vals(THD *thd, partition_element *el0, part
       thd->variables.time_zone->gmt_sec_to_TIME(&t, ts);
       val_item= static_cast<Item_datetime_literal*>(col_val->item_expression);
       DBUG_ASSERT(val_item);
-      if (val_item->set_higher(&t))
+      if (*val_item < t)
+      {
+        val_item->set_time(&t);
         col_val->fixed= 0;
       }
     }
+  }
 }
 
 
@@ -1162,7 +1168,7 @@ bool partition_info::vers_setup_2(THD * thd, bool is_create_table_ind)
     if (!table->s->stat_trx)
     {
       DBUG_ASSERT(partitions.elements > 1);
-      table->s->stat_trx= static_cast<Vers_field_stats**>(
+      table->s->stat_trx= static_cast<Vers_min_max_stats**>(
         alloc_root(&table->s->mem_root, sizeof(void *) * partitions.elements * num_columns));
       dont_stat= false;
     }
@@ -1183,8 +1189,8 @@ bool partition_info::vers_setup_2(THD * thd, bool is_create_table_ind)
       }
 
       {
-        Vers_field_stats *stat_trx_end= new (&table->s->mem_root)
-          Vers_field_stats(table->s->vers_end_field()->field_name, table->s);
+        Vers_min_max_stats *stat_trx_end= new (&table->s->mem_root)
+          Vers_min_max_stats(table->s->vers_end_field()->field_name, table->s);
         table->s->stat_trx[el->id * num_columns + STAT_TRX_END]= stat_trx_end;
       }
 

sql/partition_info.h

@@ -478,14 +478,14 @@ class partition_info : public Sql_alloc
     // TODO: cache thread-shared part_recs and increment on INSERT
     return table->file->part_records(part) >= vers_info->limit;
   }
-  Vers_field_stats& vers_stat_trx(stat_trx_field fld, uint32 part_element_id)
+  Vers_min_max_stats& vers_stat_trx(stat_trx_field fld, uint32 part_element_id)
   {
     DBUG_ASSERT(table && table->s && table->s->stat_trx);
-    Vers_field_stats* res= table->s->stat_trx[part_element_id * num_columns + fld];
+    Vers_min_max_stats* res= table->s->stat_trx[part_element_id * num_columns + fld];
     DBUG_ASSERT(res);
     return *res;
   }
-  Vers_field_stats& vers_stat_trx(stat_trx_field fld, partition_element *part)
+  Vers_min_max_stats& vers_stat_trx(stat_trx_field fld, partition_element *part)
   {
     DBUG_ASSERT(part);
     return vers_stat_trx(fld, part->id);

sql/sys_vars.ic

@@ -2495,32 +2495,11 @@ public:
 class Sys_var_vers_asof: public sys_var
 {
 public:
-  Sys_var_vers_asof(
-    const char *name_arg,
-    const char *comment,
-    int flag_args,
-    ptrdiff_t off,
-    size_t size,
-    CMD_LINE getopt,
-    enum charset_enum is_os_charset_arg,
-    const char *def_val,
-    on_check_function on_check_func=0,
-    on_update_function on_update_func=0) :
-  sys_var(
-    &all_sys_vars,
-    name_arg,
-    comment,
-    flag_args,
-    off,
-    getopt.id,
-    getopt.arg_type,
-    SHOW_CHAR,
-    (intptr) def_val,
-    0,
-    VARIABLE_NOT_IN_BINLOG,
-    on_check_func,
-    on_update_func,
-    0)
+  Sys_var_vers_asof(const char *name_arg, const char *comment, int flag_args,
+    ptrdiff_t off, size_t size, CMD_LINE getopt, enum charset_enum is_os_charset_arg,
+    const char *def_val, on_check_function on_check_func=0, on_update_function on_update_func=0) :
+  sys_var(&all_sys_vars, name_arg, comment, flag_args, off, getopt.id, getopt.arg_type,
+    SHOW_CHAR, (intptr) def_val, 0, VARIABLE_NOT_IN_BINLOG, on_check_func, on_update_func, 0)
   {
     option.var_type|= GET_STR;
     if (global_update(def_val))
@@ -2534,31 +2513,18 @@ public:
 
   bool update(String &in, st_vers_current_time &out)
   {
-    if (in.length() == 3 &&
-      0 == my_strcasecmp(
-        in.charset(),
-        "ALL",
-        in.ptr()))
+    if (in.length() == 3 && 0 == my_strcasecmp(in.charset(), "ALL", in.ptr()))
     {
       out.type= FOR_SYSTEM_TIME_ALL;
     }
-    else if (in.length() == 3 &&
-      0 == my_strcasecmp(
-        in.charset(),
-        "NOW",
-        in.ptr()))
+    else if (in.length() == 3 && 0 == my_strcasecmp(in.charset(), "NOW", in.ptr()))
     {
       out.type= FOR_SYSTEM_TIME_UNSPECIFIED;
     }
     else
     {
       MYSQL_TIME_STATUS status;
-      if (str_to_datetime(
-            in.ptr(),
-            in.length(),
-            &out.ltime,
-            flags,
-            &status) ||
+      if (str_to_datetime(in.ptr(), in.length(), &out.ltime, flags, &status) ||
           out.ltime.time_type != MYSQL_TIMESTAMP_DATETIME ||
           (status.warnings & ~MYSQL_TIME_NOTE_TRUNCATED) != 0)
       {

sql/table.h

@@ -561,7 +561,7 @@ struct TABLE_STATISTICS_CB
   bool histograms_are_read;   
 };
 
-class Vers_field_stats;
+class Vers_min_max_stats;
 
 #ifndef UINT32_MAX
 #define UINT32_MAX             (4294967295U)
@@ -755,7 +755,7 @@ struct TABLE_SHARE
   uint16 row_start_field;
   uint16 row_end_field;
   uint32 hist_part_id;
-  Vers_field_stats** stat_trx;
+  Vers_min_max_stats** stat_trx;
   ulonglong stat_serial; // guards check_range_constants() updates
 
   bool busy_rotation;