SQL: SELECT from archive table [closes #127]

mysql-test/suite/versioning/r/vtmd.result

@@ -86,7 +86,15 @@ ERROR HY000: VTMD error: `test.t0_vtmd` exists and not empty!
 drop table t0_vtmd;
 create table t0 (y int) with system versioning;
 create or replace table t0 (x int) with system versioning;
+insert into t0 values (1);
+set @t0= now(6);
 alter table t0 add column (y int);
+select * from t0 for system_time as of @t0;
+x
+1
+select * from t0;
+x	y
+1	NULL
 call check_vtmd('t0_vtmd');
 @start > 0 and @start < @inf
 1

mysql-test/suite/versioning/t/vtmd.test

@@ -86,7 +86,11 @@ create table t0 (y int) with system versioning;
 create or replace table t0 (x int) with system versioning;
 
 # alter
+insert into t0 values (1);
+set @t0= now(6);
 alter table t0 add column (y int);
+select * from t0 for system_time as of @t0;
+select * from t0;
 call check_vtmd('t0_vtmd');
 
 call drop_archives('t0_vtmd');

sql/sql_parse.cc

@@ -113,6 +113,7 @@
 
 #include "wsrep_mysqld.h"
 #include "wsrep_thd.h"
+#include "vtmd.h"
 
 static void wsrep_mysql_parse(THD *thd, char *rawbuf, uint length,
                               Parser_state *parser_state,
@@ -6373,6 +6374,21 @@ static bool execute_sqlcom_select(THD *thd, TABLE_LIST *all_tables)
   if (check_dependencies_in_with_clauses(lex->with_clauses_list))
     return 1;
 
+  if (thd->variables.vers_alter_history == VERS_ALTER_HISTORY_SURVIVE)
+  {
+    for (TABLE_LIST *table= all_tables; table; table= table->next_local)
+    {
+      if (table->vers_conditions)
+      {
+        VTMD_exists vtmd(*table);
+        if (vtmd.check_exists(thd))
+          return 1;
+        if (vtmd.exists && vtmd.setup_select(thd))
+          return 1;
+      }
+    }
+  }
+
   if (!(res= open_and_lock_tables(thd, all_tables, TRUE, 0)))
   {
     if (lex->describe)

sql/sql_show.cc

@@ -1280,12 +1280,15 @@ mysqld_show_create(THD *thd, TABLE_LIST *table_list)
     if (vtmd.find_archive_name(thd, archive_name))
       goto exit;
 
-    archive.init_one_table(table_list->db, table_list->db_length, archive_name.ptr(),
-                      archive_name.length(), archive_name.ptr(), TL_READ);
+    if (archive_name.length() > 0)
+    {
+      archive.init_one_table(table_list->db, table_list->db_length, archive_name.ptr(),
+                        archive_name.length(), archive_name.ptr(), TL_READ);
 
-    archive.alias= table_list->table_name;
-    archive.vers_force_alias= true;
-    table_list= &archive;
+      archive.alias= table_list->table_name;
+      archive.vers_force_alias= true;
+      table_list= &archive;
+    }
   }
 
   if (mysqld_show_create_get_fields(thd, table_list, &field_list, &buffer))

sql/vtmd.cc

@@ -7,6 +7,8 @@
 #include "table_cache.h" // tdc_remove_table()
 #include "key.h"
 #include "sql_show.h"
+#include "sql_parse.h"
+#include "sql_lex.h"
 
 LString VERS_VTMD_TEMPLATE(C_STRING_WITH_LEN("vtmd_template"));
 
@@ -546,8 +548,6 @@ VTMD_table::find_archive_name(THD *thd, String &out)
     if (select->skip_record(thd) > 0)
     {
       vtmd.table->field[FLD_ARCHIVE_NAME]->val_str(&out);
-      if (out.length() == 0) // Handle AS OF NOW or RENAME TABLE case
-        out.set(about.table_name, about.table_name_length, system_charset_info);
       break;
     }
   }
@@ -644,3 +644,20 @@ VTMD_table::get_archive_tables(THD *thd, const char *db, size_t db_length,
 
   return false;
 }
+
+bool VTMD_table::setup_select(THD* thd)
+{
+  SString archive_name;
+  if (find_archive_name(thd, archive_name))
+    return true;
+
+  if (archive_name.length() == 0)
+    return false;
+
+  about.table_name= (char *) thd->memdup(archive_name.c_ptr_safe(), archive_name.length() + 1);
+  about.table_name_length= archive_name.length();
+  DBUG_ASSERT(!about.mdl_request.ticket);
+  about.mdl_request.init(MDL_key::TABLE, about.db, about.table_name,
+                         about.mdl_request.type, about.mdl_request.duration);
+  return false;
+}

sql/vtmd.h

@@ -52,7 +52,7 @@ class VTMD_table
 
 protected:
   TABLE_LIST vtmd;
-  const TABLE_LIST &about;
+  TABLE_LIST &about;
   SString_t vtmd_name;
 
 private: