From f79c4469ff8a17dee54f41786b76197dc2e17626 Mon Sep 17 00:00:00 2001
From: Eugene Kosov <claprix@yandex.ru>
Date: Mon, 25 Sep 2017 11:29:16 +0300
Subject: [PATCH] SQL: helpers to get archive tables list [closes #199]

---
 sql/sql_show.cc |  2 +-
 sql/sql_show.h  |  3 +++
 sql/vtmd.cc     | 71 +++++++++++++++++++++++++++++++++++++++++++++++++
 sql/vtmd.h      |  4 +++
 4 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index 30fd1b43e4c..ac340892505 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -4218,7 +4218,7 @@ int schema_tables_add(THD *thd, Dynamic_array<LEX_STRING*> *files,
     @retval       2           Not fatal error; Safe to ignore this file list
 */
 
-static int
+int
 make_table_name_list(THD *thd, Dynamic_array<LEX_STRING*> *table_names,
                      LEX *lex, LOOKUP_FIELD_VALUES *lookup_field_vals,
                      LEX_STRING *db_name)
diff --git a/sql/sql_show.h b/sql/sql_show.h
index e93b855450c..03ff539e959 100644
--- a/sql/sql_show.h
+++ b/sql/sql_show.h
@@ -199,6 +199,9 @@ typedef struct st_lookup_field_values
   bool wild_table_value;
 } LOOKUP_FIELD_VALUES;  
 
+int make_table_name_list(THD *thd, Dynamic_array<LEX_STRING *> *table_names,
+                         LEX *lex, LOOKUP_FIELD_VALUES *lookup_field_vals,
+                         LEX_STRING *db_name);
 
 /*
   INFORMATION_SCHEMA: Execution plan for get_all_tables() call
diff --git a/sql/vtmd.cc b/sql/vtmd.cc
index 58d9bb311bb..aa9245570f4 100644
--- a/sql/vtmd.cc
+++ b/sql/vtmd.cc
@@ -6,6 +6,7 @@
 #include "sql_select.h"
 #include "table_cache.h" // tdc_remove_table()
 #include "key.h"
+#include "sql_show.h"
 
 LString VERS_VTMD_TEMPLATE(C_STRING_WITH_LEN("vtmd_template"));
 
@@ -573,3 +574,73 @@ err:
   close_log_table(thd, &open_tables_backup);
   return error ? true : false;
 }
+
+Dynamic_array<String> VTMD_table::get_archive_tables(THD *thd)
+{
+  Dynamic_array<String> result;
+
+  Dynamic_array<LEX_STRING *> vtmd_tables= get_vtmd_tables(thd);
+  for (uint i= 0; i < vtmd_tables.elements(); i++)
+  {
+    LEX_STRING table_name= *vtmd_tables.at(i);
+
+    Open_tables_backup open_tables_backup;
+    TABLE_LIST table_list;
+    // Assume VTMD tables belongs to current db.
+    table_list.init_one_table(thd->db, strlen(thd->db),
+                              LEX_STRING_WITH_LEN(table_name), table_name.str,
+                              TL_READ);
+
+    TABLE *table= open_log_table(thd, &table_list, &open_tables_backup);
+    if (!table)
+      return result;
+
+    READ_RECORD read_record;
+    int error= 0;
+    SQL_SELECT *sql_select= make_select(table, 0, 0, NULL, NULL, 0, &error);
+    if (error)
+      goto error1;
+    if (error = init_read_record(&read_record, thd, table, sql_select, NULL, 1, 1,
+                         false))
+      goto error2;
+
+    while (!(error= read_record.read_record(&read_record)))
+    {
+      Field *field= table->field[FLD_ARCHIVE_NAME];
+      if (field->is_null())
+        continue;
+
+      String archive_name;
+      field->val_str(&archive_name);
+      archive_name.set_ascii(strmake_root(thd->mem_root, archive_name.c_ptr(),
+                                          archive_name.length()),
+                             archive_name.length());
+      result.push(archive_name);
+    }
+
+    end_read_record(&read_record);
+  error2:
+    delete sql_select;
+  error1:
+    close_log_table(thd, &open_tables_backup);
+
+    if (error)
+      break;
+  }
+
+  return result;
+}
+
+Dynamic_array<LEX_STRING *> get_vtmd_tables(THD *thd)
+{
+  // Note function retrieves table names from current db only.
+  LOOKUP_FIELD_VALUES lookup_field_values= {
+      *thd->make_lex_string(thd->db, strlen(thd->db)),
+      *thd->make_lex_string(C_STRING_WITH_LEN("%_vtmd")), false, true};
+
+  Dynamic_array<LEX_STRING *> table_names;
+  make_table_name_list(thd, &table_names, thd->lex, &lookup_field_values,
+                       &lookup_field_values.db_value);
+
+  return table_names;
+}
diff --git a/sql/vtmd.h b/sql/vtmd.h
index 8588462f83f..8a838dc2f88 100644
--- a/sql/vtmd.h
+++ b/sql/vtmd.h
@@ -87,8 +87,12 @@ public:
   }
 
   bool find_archive_name(THD *thd, String &out);
+
+  static Dynamic_array<String> get_archive_tables(THD *thd);
 };
 
+Dynamic_array<LEX_STRING *> get_vtmd_tables(THD *thd);
+
 class VTMD_exists : public VTMD_table
 {
 protected: