WL#3337 (Events new architecture)

Cut number 6. Move code from sql_show.cc to event_db_repository.cc
that more belongs to the latter.


sql/event_db_repository.cc:
  move code that works with mysql.event from sql_show.cc to 
  event_db_repository.cc . Route through Event_db_repository's interface
  which is proxied by class Events. The code relies on a function from
  sql_show.cc which does the actual storage in the schema table. I think
  it's better to leave the function there because the structure of 
  I_S.EVENTS is defined in sql_show.cc
sql/event_db_repository.h:
  I_S / SHOW EVENTS handling hooks
sql/event_scheduler.cc:
  use the pointer to db_repository which Event_scheduler already has
sql/events.cc:
  Put a comment to get_instance
sql/events.h:
  callback for I_S (sql_show.cc)
sql/sql_show.cc:
  move code that belongs more to Event_db_repository than to here.
  Use a callback of class Events. Only 1 function is left here, because
  it copies data into the actual rows of I_S.EVENTS and belongs to this file.
sql/sql_show.h:
  export this function will be called from event_db_repository.cc

sql/event_db_repository.cc

@@ -20,6 +20,7 @@
 #include "sp_head.h"
 #include "sp.h"
 #include "events.h"
+#include "sql_show.h"
 
 #define EVEX_DB_FIELD_LEN 64
 #define EVEX_NAME_FIELD_LEN 64
@@ -188,8 +189,7 @@ evex_fill_row(THD *thd, TABLE *table, Event_timed *et, my_bool is_update)
   if (et->expression)
   {
     table->field[ET_FIELD_INTERVAL_EXPR]->set_notnull();
-    table->field[ET_FIELD_INTERVAL_EXPR]->
-                                          store((longlong)et->expression, true);
+    table->field[ET_FIELD_INTERVAL_EXPR]->store((longlong)et->expression, true);
 
     table->field[ET_FIELD_TRANSIENT_INTERVAL]->set_notnull();
     /*
@@ -276,16 +276,181 @@ evex_db_find_event_by_name(THD *thd, const LEX_STRING dbname,
 }
 
 
+/*
+  Performs an index scan of event_table (mysql.event) and fills schema_table.
+
+  Synopsis
+    Event_db_repository::index_read_for_db_for_i_s()
+      thd          Thread
+      schema_table The I_S.EVENTS table
+      event_table  The event table to use for loading (mysql.event)
+
+  Returns
+    0  OK
+    1  Error
+*/
+
+int
+Event_db_repository::index_read_for_db_for_i_s(THD *thd, TABLE *schema_table,
+                                               TABLE *event_table, char *db)
+{
+  int ret=0;
+  CHARSET_INFO *scs= system_charset_info;
+  KEY *key_info;
+  uint key_len;
+  byte *key_buf= NULL;
+  LINT_INIT(key_buf);
+
+  DBUG_ENTER("Event_db_repository::index_read_for_db_for_i_s");
+
+  DBUG_PRINT("info", ("Using prefix scanning on PK"));
+  event_table->file->ha_index_init(0, 1);
+  event_table->field[ET_FIELD_DB]->store(db, strlen(db), scs);
+  key_info= event_table->key_info;
+  key_len= key_info->key_part[0].store_length;
+
+  if (!(key_buf= (byte *)alloc_root(thd->mem_root, key_len)))
+  {
+    ret= 1;
+    /* don't send error, it would be done by sql_alloc_error_handler() */
+  }
+  else
+  {
+    key_copy(key_buf, event_table->record[0], key_info, key_len);
+    if (!(ret= event_table->file->index_read(event_table->record[0], key_buf,
+                                             key_len, HA_READ_PREFIX)))
+    {
+      DBUG_PRINT("info",("Found rows. Let's retrieve them. ret=%d", ret));
+      do
+      {
+        ret= copy_event_to_schema_table(thd, schema_table, event_table);
+        if (ret == 0)
+          ret= event_table->file->index_next_same(event_table->record[0],
+                                                  key_buf, key_len); 
+      } while (ret == 0);
+    }
+    DBUG_PRINT("info", ("Scan finished. ret=%d", ret));
+  }
+  event_table->file->ha_index_end(); 
+  /*  ret is guaranteed to be != 0 */
+  if (ret == HA_ERR_END_OF_FILE || ret == HA_ERR_KEY_NOT_FOUND)
+    DBUG_RETURN(0);
+  DBUG_RETURN(1);
+}
+
+
+/*
+  Performs a table scan of event_table (mysql.event) and fills schema_table.
+
+  Synopsis
+    Events_db_repository::table_scan_all_for_i_s()
+      thd          Thread
+      schema_table The I_S.EVENTS in memory table
+      event_table  The event table to use for loading.
+
+  Returns
+    0  OK
+    1  Error
+*/
+
+int
+Event_db_repository::table_scan_all_for_i_s(THD *thd, TABLE *schema_table,
+                                            TABLE *event_table)
+{
+  int ret;
+  READ_RECORD read_record_info;
+
+  DBUG_ENTER("Event_db_repository::table_scan_all_for_i_s");
+  init_read_record(&read_record_info, thd, event_table, NULL, 1, 0);
+
+  /*
+    rr_sequential, in read_record(), returns 137==HA_ERR_END_OF_FILE,
+    but rr_handle_error returns -1 for that reason. Thus, read_record()
+    returns -1 eventually.
+  */
+  do
+  {
+    ret= read_record_info.read_record(&read_record_info);
+    if (ret == 0)
+      ret= copy_event_to_schema_table(thd, schema_table, event_table);
+  }
+  while (ret == 0);
+
+  DBUG_PRINT("info", ("Scan finished. ret=%d", ret));
+  end_read_record(&read_record_info);
+
+  /*  ret is guaranteed to be != 0 */
+  DBUG_RETURN(ret == -1? 0:1);
+}
+
+
+/*
+  Fills I_S.EVENTS with data loaded from mysql.event. Also used by
+  SHOW EVENTS
+
+  Synopsis
+    Event_db_repository::fill_schema_events()
+      thd     Thread
+      tables  The schema table
+      db      If not NULL then get events only from this schema
+
+  Returns
+    0  OK
+    1  Error
+*/
+
+int
+Event_db_repository::fill_schema_events(THD *thd, TABLE_LIST *tables, char *db)
+{
+  TABLE *schema_table= tables->table;
+  TABLE *event_table= NULL;
+  Open_tables_state backup;
+  int ret= 0;
+
+  DBUG_ENTER("Event_db_repository::fill_schema_events");
+  DBUG_PRINT("info",("db=%s", db? db:"(null)"));
+
+  thd->reset_n_backup_open_tables_state(&backup);
+  if (open_event_table(thd, TL_READ, &event_table))
+  {
+    sql_print_error("Table mysql.event is damaged.");
+    thd->restore_backup_open_tables_state(&backup);
+    DBUG_RETURN(1);
+  }
+
+  /*
+    1. SELECT I_S => use table scan. I_S.EVENTS does not guarantee order
+                     thus we won't order it. OTOH, SHOW EVENTS will be
+                     ordered.
+    2. SHOW EVENTS => PRIMARY KEY with prefix scanning on (db)
+       Reasoning: Events are per schema, therefore a scan over an index
+                  will save use from doing a table scan and comparing
+                  every single row's `db` with the schema which we show.
+  */
+  if (db)
+    ret= index_read_for_db_for_i_s(thd, schema_table, event_table, db);
+  else
+    ret= table_scan_all_for_i_s(thd, schema_table, event_table);
+
+  close_thread_tables(thd);
+  thd->restore_backup_open_tables_state(&backup);
+
+  DBUG_PRINT("info", ("Return code=%d", ret));
+  DBUG_RETURN(ret);
+}
+
+
 /*
   Looks for a named event in mysql.event and in case of success returns
   an object will data loaded from the table.
 
   SYNOPSIS
-    db_find_event()
+    Event_db_repository::find_event()
       thd      THD
       name     the name of the event to find
       ett      event's data if event is found
       tbl      TABLE object to use when not NULL
+      root     On which root to load the event
 
   NOTES
     1) Use sp_name for look up, return in **ett if found
@@ -308,7 +473,7 @@ Event_db_repository::find_event(THD *thd, sp_name *name, Event_timed **ett,
 
   if (tbl)
     table= tbl;
-  else if (Events::get_instance()->db_repository.open_event_table(thd, TL_READ, &table))
+  else if (open_event_table(thd, TL_READ, &table))
   {
     my_error(ER_EVENT_OPEN_TABLE_FAILED, MYF(0));
     ret= EVEX_GENERAL_ERROR;

sql/event_db_repository.h

@@ -43,6 +43,17 @@ evex_db_find_event_by_name(THD *thd, const LEX_STRING dbname,
                            const LEX_STRING ev_name,
                            TABLE *table);
 
+int
+events_table_index_read_for_db(THD *thd, TABLE *schema_table,
+                               TABLE *event_table);
+
+int
+events_table_scan_all(THD *thd, TABLE *schema_table, TABLE *event_table);
+
+int
+fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */);
+
+
 class Event_queue_element;
 
 class Event_db_repository
@@ -57,9 +68,6 @@ class Event_db_repository
   void
   deinit_repository();
 
-  int
-  open_event_table(THD *thd, enum thr_lock_type lock_type, TABLE **table);
-
   int
   create_event(THD *thd, Event_timed *et, my_bool create_if_not,
               uint *rows_affected);
@@ -86,11 +94,23 @@ class Event_db_repository
 
   int
   find_event_by_name(THD *thd, LEX_STRING db, LEX_STRING name, TABLE *table);
-private:
 
+  int
+  open_event_table(THD *thd, enum thr_lock_type lock_type, TABLE **table);
+
+  int
+  fill_schema_events(THD *thd, TABLE_LIST *tables, char *db);
+
+private:
   int
   drop_events_by_field(THD *thd, enum enum_events_table_field field,
                        LEX_STRING field_value);
+  int
+  index_read_for_db_for_i_s(THD *thd, TABLE *schema_table, TABLE *event_table,
+                            char *db);
+
+  int
+  table_scan_all_for_i_s(THD *thd, TABLE *schema_table, TABLE *event_table);
 
   MEM_ROOT repo_root;
 

sql/event_scheduler.cc

@@ -2159,7 +2159,7 @@ Event_scheduler::load_events_from_db(THD *thd)
     DBUG_RETURN(EVEX_GENERAL_ERROR);
   }
 
-  if ((ret= Events::get_instance()->open_event_table(thd, TL_READ, &table)))
+  if ((ret= db_repository->open_event_table(thd, TL_READ, &table)))
   {
     sql_print_error("SCHEDULER: Table mysql.event is damaged. Can not open.");
     DBUG_RETURN(EVEX_OPEN_TABLE_FAILED);

sql/events.cc

@@ -88,6 +88,15 @@ int sortcmp_lex_string(LEX_STRING s, LEX_STRING t, CHARSET_INFO *cs)
                                   (unsigned char *) t.str,t.length, 0);
 }
 
+/*
+  Accessor for the singleton instance.
+
+  SYNOPSIS
+    Events::get_instance()
+
+  RETURN VALUE
+    address  
+*/
 
 Events *
 Events::get_instance()
@@ -110,7 +119,7 @@ Events::get_instance()
       interval - the interval type (for instance YEAR_MONTH)
       expression - the value in the lowest entity
 
-  RETURNS
+  RETURN VALUE
    0 - OK
    1 - Error
 */
@@ -562,6 +571,42 @@ Events::dump_internal_status(THD *thd)
 }
 
 
+/*
+  Proxy for Event_db_repository::fill_schema_events.
+  Callback for I_S from sql_show.cc
+
+  SYNOPSIS
+    Events::fill_schema_events()
+      thd     Thread
+      tables  The schema table
+      cond    Unused
+
+  RETURN VALUE
+    0  OK
+    !0 Error
+*/
+
+int
+Events::fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */)
+{
+  char *db= NULL;
+  DBUG_ENTER("Events::fill_schema_events");
+  /*
+    If it's SHOW EVENTS then thd->lex->select_lex.db is guaranteed not to
+    be NULL. Let's do an assert anyway.
+  */
+  if (thd->lex->orig_sql_command == SQLCOM_SHOW_EVENTS)
+  {
+    DBUG_ASSERT(thd->lex->select_lex.db);
+    if (check_access(thd, EVENT_ACL, thd->lex->select_lex.db, 0, 0, 0,
+                     is_schema_db(thd->lex->select_lex.db)))
+      DBUG_RETURN(1);
+    db= thd->lex->select_lex.db;
+  }
+  DBUG_RETURN(get_instance()->db_repository.fill_schema_events(thd, tables, db));
+}
+
+
 /*
   Inits Events mutexes
 

sql/events.h

@@ -91,6 +91,9 @@ class Events
   int
   drop_schema_events(THD *thd, char *db);
 
+  static int
+  fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */);
+  
   int
   dump_internal_status(THD *thd);
 

sql/sql_show.cc

@@ -4160,7 +4160,7 @@ extern LEX_STRING interval_type_to_name[];
     1  Error
 */
 
-static int
+int
 copy_event_to_schema_table(THD *thd, TABLE *sch_table, TABLE *event_table)
 {
   const char *wild= thd->lex->wild ? thd->lex->wild->ptr() : NullS;
@@ -4295,183 +4295,6 @@ copy_event_to_schema_table(THD *thd, TABLE *sch_table, TABLE *event_table)
 }
 
 
-/*
-  Performs an index scan of event_table (mysql.event) and fills schema_table.
-
-  Synopsis
-    events_table_index_read_for_db()
-      thd          Thread
-      schema_table The I_S.EVENTS table
-      event_table  The event table to use for loading (mysql.event)
-
-  Returns
-    0  OK
-    1  Error
-*/
-
-static
-int events_table_index_read_for_db(THD *thd, TABLE *schema_table,
-                                TABLE *event_table)
-{
-  int ret=0;
-  CHARSET_INFO *scs= system_charset_info;
-  KEY *key_info;
-  uint key_len;
-  byte *key_buf= NULL;
-  LINT_INIT(key_buf);
-
-  DBUG_ENTER("schema_events_do_index_scan");
-
-  DBUG_PRINT("info", ("Using prefix scanning on PK"));
-  event_table->file->ha_index_init(0, 1);
-  event_table->field[ET_FIELD_DB]->
-        store(thd->lex->select_lex.db, strlen(thd->lex->select_lex.db), scs);
-  key_info= event_table->key_info;
-  key_len= key_info->key_part[0].store_length;
-
-  if (!(key_buf= (byte *)alloc_root(thd->mem_root, key_len)))
-  {
-    ret= 1;
-    /* don't send error, it would be done by sql_alloc_error_handler() */
-  }
-  else
-  {
-    key_copy(key_buf, event_table->record[0], key_info, key_len);
-    if (!(ret= event_table->file->index_read(event_table->record[0], key_buf,
-                                             key_len, HA_READ_PREFIX)))
-    {
-      DBUG_PRINT("info",("Found rows. Let's retrieve them. ret=%d", ret));
-      do
-      {
-        ret= copy_event_to_schema_table(thd, schema_table, event_table);
-        if (ret == 0)
-          ret= event_table->file->index_next_same(event_table->record[0],
-                                                  key_buf, key_len); 
-      } while (ret == 0);
-    }
-    DBUG_PRINT("info", ("Scan finished. ret=%d", ret));
-  }
-  event_table->file->ha_index_end(); 
-  /*  ret is guaranteed to be != 0 */
-  if (ret == HA_ERR_END_OF_FILE || ret == HA_ERR_KEY_NOT_FOUND)
-    DBUG_RETURN(0);
-  DBUG_RETURN(1);
-}
-
-
-/*
-  Performs a table scan of event_table (mysql.event) and fills schema_table.
-
-  Synopsis
-    events_table_scan_all()
-      thd          Thread
-      schema_table The I_S.EVENTS in memory table
-      event_table  The event table to use for loading.
-
-  Returns
-    0  OK
-    1  Error
-*/
-
-static
-int events_table_scan_all(THD *thd, TABLE *schema_table,
-                                TABLE *event_table)
-{
-  int ret;
-  READ_RECORD read_record_info;
-
-  DBUG_ENTER("schema_events_do_table_scan");
-  init_read_record(&read_record_info, thd, event_table, NULL, 1, 0);
-
-  /*
-    rr_sequential, in read_record(), returns 137==HA_ERR_END_OF_FILE,
-    but rr_handle_error returns -1 for that reason. Thus, read_record()
-    returns -1 eventually.
-  */
-  do
-  {
-    ret= read_record_info.read_record(&read_record_info);
-    if (ret == 0)
-      ret= copy_event_to_schema_table(thd, schema_table, event_table);
-  }
-  while (ret == 0);
-
-  DBUG_PRINT("info", ("Scan finished. ret=%d", ret));
-  end_read_record(&read_record_info);
-
-  /*  ret is guaranteed to be != 0 */
-  DBUG_RETURN(ret == -1? 0:1);
-}
-
-
-/*
-  Fills I_S.EVENTS with data loaded from mysql.event. Also used by
-  SHOW EVENTS
-
-  Synopsis
-    fill_schema_events()
-      thd     Thread
-      tables  The schema table
-      cond    Unused
-
-  Returns
-    0  OK
-    1  Error
-*/
-
-int fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */)
-{
-  TABLE *schema_table= tables->table;
-  TABLE *event_table= NULL;
-  Open_tables_state backup;
-  int ret= 0;
-
-  DBUG_ENTER("fill_schema_events");
-  /*
-    If it's SHOW EVENTS then thd->lex->select_lex.db is guaranteed not to
-    be NULL. Let's do an assert anyway.
-  */
-  if (thd->lex->orig_sql_command == SQLCOM_SHOW_EVENTS)
-  {
-    DBUG_ASSERT(thd->lex->select_lex.db);
-    if (check_access(thd, EVENT_ACL, thd->lex->select_lex.db, 0, 0, 0,
-                     is_schema_db(thd->lex->select_lex.db)))
-      DBUG_RETURN(1);
-  }
-
-  DBUG_PRINT("info",("db=%s", thd->lex->select_lex.db?
-              thd->lex->select_lex.db:"(null)"));
-
-  thd->reset_n_backup_open_tables_state(&backup);
-  if (Events::get_instance()->open_event_table(thd, TL_READ, &event_table))
-  {
-    sql_print_error("Table mysql.event is damaged.");
-    thd->restore_backup_open_tables_state(&backup);
-    DBUG_RETURN(1);
-  }
-
-  /*
-    1. SELECT I_S => use table scan. I_S.EVENTS does not guarantee order
-                     thus we won't order it. OTOH, SHOW EVENTS will be
-                     ordered.
-    2. SHOW EVENTS => PRIMARY KEY with prefix scanning on (db)
-       Reasoning: Events are per schema, therefore a scan over an index
-                  will save use from doing a table scan and comparing
-                  every single row's `db` with the schema which we show.
-  */
-  if (thd->lex->orig_sql_command == SQLCOM_SHOW_EVENTS)
-    ret= events_table_index_read_for_db(thd, schema_table, event_table);
-  else
-    ret= events_table_scan_all(thd, schema_table, event_table);
-
-  close_thread_tables(thd);
-  thd->restore_backup_open_tables_state(&backup);
-
-  DBUG_PRINT("info", ("Return code=%d", ret));
-  DBUG_RETURN(ret);
-}
-
-
 int fill_open_tables(THD *thd, TABLE_LIST *tables, COND *cond)
 {
   DBUG_ENTER("fill_open_tables");
@@ -5568,7 +5391,7 @@ ST_SCHEMA_TABLE schema_tables[]=
   {"ENGINES", engines_fields_info, create_schema_table,
    fill_schema_engines, make_old_format, 0, -1, -1, 0},
   {"EVENTS", events_fields_info, create_schema_table,
-   fill_schema_events, make_old_format, 0, -1, -1, 0},
+   Events::fill_schema_events, make_old_format, 0, -1, -1, 0},
   {"FILES", files_fields_info, create_schema_table,
    fill_schema_files, 0, 0, -1, -1, 0},
   {"KEY_COLUMN_USAGE", key_column_usage_fields_info, create_schema_table,

sql/sql_show.h

@@ -14,4 +14,6 @@ int store_create_info(THD *thd, TABLE_LIST *table_list, String *packet,
                       HA_CREATE_INFO  *create_info_arg);
 int view_store_create_info(THD *thd, TABLE_LIST *table, String *buff);
 
+int copy_event_to_schema_table(THD *thd, TABLE *sch_table, TABLE *event_table);
+
 #endif /* SQL_SHOW_H */