MDEV-17096 Pushdown of simple derived tables to storage engines

MDEV-17631 select_handler for a full query pushdown

Interfaces + Proof of Concept for federatedx with test cases.

The interfaces have been developed for integration of ColumnStore engine.

4 files changed, 357 insertions, 1 deletions

diff --git a/storage/federatedx/federatedx_pushdown.cc b/storage/federatedx/federatedx_pushdown.cc
new file mode 100644
index 00000000000..bfe421c8ab2
--- /dev/null
+++ b/storage/federatedx/federatedx_pushdown.cc
@@ -0,0 +1,273 @@
+/*
+   Copyright (c) 2019 MariaDB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+/* !!! For inclusion into ha_federatedx.cc */
+
+static derived_handler*
+create_federatedx_derived_handler(THD* thd, TABLE_LIST *derived)
+{
+  ha_federatedx_derived_handler* handler = NULL;
+  handlerton *ht= 0;
+
+  SELECT_LEX_UNIT *unit= derived->derived;
+
+  for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
+  {
+    if (!(sl->join))
+      return 0;
+    for (TABLE_LIST *tbl= sl->join->tables_list; tbl; tbl= tbl->next_local)
+    {
+      if (!tbl->table)
+	return 0;
+      if (!ht)
+        ht= tbl->table->file->partition_ht();
+      else if (ht != tbl->table->file->partition_ht())
+        return 0;
+    }
+  }
+  
+  handler= new ha_federatedx_derived_handler(thd, derived);
+
+  return handler;
+}
+
+
+/* 
+  Implementation class of the derived_handler interface for FEDERATEDX:
+  class implementation
+*/
+
+ha_federatedx_derived_handler::ha_federatedx_derived_handler(THD *thd,
+                                                             TABLE_LIST *dt)
+  : derived_handler(thd, federatedx_hton),
+    share(NULL), txn(NULL), iop(NULL), stored_result(NULL)
+{
+  derived= dt;
+}
+
+ha_federatedx_derived_handler::~ha_federatedx_derived_handler() {}
+
+int ha_federatedx_derived_handler::init_scan()
+{
+  char query_buff[4096];
+  THD *thd;
+  int rc= 0;
+
+  DBUG_ENTER("ha_federatedx_derived_handler::init_scan");
+
+  TABLE *table= derived->get_first_table()->table;
+  ha_federatedx *h= (ha_federatedx *) table->file;
+  iop= &h->io;
+  share= get_share(table->s->table_name.str, table);
+  thd= table->in_use;
+  txn= h->get_txn(thd);
+  if ((rc= txn->acquire(share, thd, TRUE, iop)))
+    DBUG_RETURN(rc);
+  
+  String derived_query(query_buff, sizeof(query_buff), thd->charset());
+  derived_query.length(0);
+  derived->derived->print(&derived_query, QT_ORDINARY);
+  
+  if ((*iop)->query(derived_query.ptr(), derived_query.length()))
+    goto err;
+
+  stored_result= (*iop)->store_result();
+  if (!stored_result)
+      goto err;
+
+  DBUG_RETURN(0);
+
+err:
+  DBUG_RETURN(HA_FEDERATEDX_ERROR_WITH_REMOTE_SYSTEM);
+}
+      
+int ha_federatedx_derived_handler::next_row()
+{
+  int rc;
+  FEDERATEDX_IO_ROW *row;
+  ulong *lengths;
+  Field **field;
+  int column= 0;
+  Time_zone *saved_time_zone= table->in_use->variables.time_zone;
+  DBUG_ENTER("ha_federatedx_derived_handler::next_row");
+
+  if ((rc= txn->acquire(share, table->in_use, TRUE, iop)))
+    DBUG_RETURN(rc);
+
+  if (!(row= (*iop)->fetch_row(stored_result)))
+    DBUG_RETURN(HA_ERR_END_OF_FILE);
+
+  /* Convert row to internal format */
+  table->in_use->variables.time_zone= UTC;
+  lengths= (*iop)->fetch_lengths(stored_result);
+
+  for (field= table->field; *field; field++, column++)
+  {
+    if ((*iop)->is_column_null(row, column))
+       (*field)->set_null();
+    else
+    {
+      (*field)->set_notnull();
+      (*field)->store((*iop)->get_column_data(row, column),
+                      lengths[column], &my_charset_bin);
+    }
+  }
+  table->in_use->variables.time_zone= saved_time_zone;
+
+  DBUG_RETURN(rc);
+}
+
+int ha_federatedx_derived_handler::end_scan()
+{
+  DBUG_ENTER("ha_federatedx_derived_handler::end_scan");
+
+  (*iop)->free_result(stored_result);
+
+  free_share(txn, share);
+
+  DBUG_RETURN(0);
+}
+
+void ha_federatedx_derived_handler::print_error(int, unsigned long)
+{
+}
+
+
+static select_handler*
+create_federatedx_select_handler(THD* thd, SELECT_LEX *sel)
+{
+  ha_federatedx_select_handler* handler = NULL;
+  handlerton *ht= 0;
+
+  for (TABLE_LIST *tbl= thd->lex->query_tables; tbl; tbl= tbl->next_global)
+  {
+    if (!tbl->table)
+      return 0;
+    if (!ht)
+      ht= tbl->table->file->partition_ht();
+    else if (ht != tbl->table->file->partition_ht())
+      return 0;
+  }
+
+  handler= new ha_federatedx_select_handler(thd, sel);
+
+  return handler;
+}
+
+/* 
+  Implementation class of the select_handler interface for FEDERATEDX:
+  class implementation
+*/
+
+ha_federatedx_select_handler::ha_federatedx_select_handler(THD *thd,
+                                                           SELECT_LEX *sel)
+  : select_handler(thd, federatedx_hton),
+    share(NULL), txn(NULL), iop(NULL), stored_result(NULL) 
+{
+  select= sel;
+}
+
+ha_federatedx_select_handler::~ha_federatedx_select_handler() {}
+
+int ha_federatedx_select_handler::init_scan()
+{
+  int rc= 0;
+
+  DBUG_ENTER("ha_federatedx_select_handler::init_scan");
+
+  TABLE *table= 0;
+  for (TABLE_LIST *tbl= thd->lex->query_tables; tbl; tbl= tbl->next_global)
+  {
+    if (!tbl->table)
+      continue;
+    table= tbl->table;
+    break;
+  }
+  ha_federatedx *h= (ha_federatedx *) table->file;
+  iop= &h->io;
+  share= get_share(table->s->table_name.str, table);
+  txn= h->get_txn(thd);
+  if ((rc= txn->acquire(share, thd, TRUE, iop)))
+    DBUG_RETURN(rc);
+
+  if ((*iop)->query(thd->query(), thd->query_length()))
+    goto err;
+
+  stored_result= (*iop)->store_result();
+  if (!stored_result)
+      goto err;
+
+  DBUG_RETURN(0);
+
+err:
+  DBUG_RETURN(HA_FEDERATEDX_ERROR_WITH_REMOTE_SYSTEM);
+}
+
+int ha_federatedx_select_handler::next_row()
+{
+  int rc= 0;
+  FEDERATEDX_IO_ROW *row;
+  ulong *lengths;
+  Field **field;
+  int column= 0;
+  Time_zone *saved_time_zone= table->in_use->variables.time_zone;
+  DBUG_ENTER("ha_federatedx_select_handler::next_row");
+
+  if ((rc= txn->acquire(share, table->in_use, TRUE, iop)))
+    DBUG_RETURN(rc);
+
+  if (!(row= (*iop)->fetch_row(stored_result)))
+    DBUG_RETURN(HA_ERR_END_OF_FILE);
+
+  /* Convert row to internal format */
+  table->in_use->variables.time_zone= UTC;
+  lengths= (*iop)->fetch_lengths(stored_result);
+
+  for (field= table->field; *field; field++, column++)
+  {
+    if ((*iop)->is_column_null(row, column))
+       (*field)->set_null();
+    else
+    {
+      (*field)->set_notnull();
+      (*field)->store((*iop)->get_column_data(row, column),
+                      lengths[column], &my_charset_bin);
+    }
+  }
+  table->in_use->variables.time_zone= saved_time_zone;
+
+  DBUG_RETURN(rc);
+}
+
+int ha_federatedx_select_handler::end_scan()
+{
+  DBUG_ENTER("ha_federatedx_derived_handler::end_scan");
+
+  free_tmp_table(thd, table);
+  table= 0;
+
+  (*iop)->free_result(stored_result);
+
+  free_share(txn, share);
+
+  DBUG_RETURN(0);
+}
+
+void ha_federatedx_select_handler::print_error(int, unsigned long)
+{
+}
+
+
diff --git a/storage/federatedx/federatedx_pushdown.h b/storage/federatedx/federatedx_pushdown.h
new file mode 100644
index 00000000000..961571b972c
--- /dev/null
+++ b/storage/federatedx/federatedx_pushdown.h
@@ -0,0 +1,63 @@
+/*
+   Copyright (c) 2019 MariaDB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+#include "derived_handler.h"
+#include "select_handler.h"
+
+/* 
+  Implementation class of the derived_handler interface for FEDERATEDX:
+  class declaration
+*/
+
+class ha_federatedx_derived_handler: public derived_handler
+{
+private:
+  FEDERATEDX_SHARE *share;
+  federatedx_txn *txn;
+  federatedx_io **iop;
+  FEDERATEDX_IO_RESULT *stored_result;
+
+public:
+  ha_federatedx_derived_handler(THD* thd_arg, TABLE_LIST *tbl);
+  ~ha_federatedx_derived_handler();
+  int init_scan();
+  int next_row();
+  int end_scan();
+  void print_error(int, unsigned long);
+};
+
+
+/* 
+  Implementation class of the select_handler interface for FEDERATEDX:
+  class declaration
+*/
+
+class ha_federatedx_select_handler: public select_handler
+{
+private:
+  FEDERATEDX_SHARE *share;
+  federatedx_txn *txn;
+  federatedx_io **iop;
+  FEDERATEDX_IO_RESULT *stored_result;
+
+public:
+  ha_federatedx_select_handler(THD* thd_arg, SELECT_LEX *sel);
+  ~ha_federatedx_select_handler();
+  int init_scan();
+  int next_row();
+  int end_scan();
+  void print_error(int, unsigned long);
+};
diff --git a/storage/federatedx/ha_federatedx.cc b/storage/federatedx/ha_federatedx.cc
index 74d547cb674..918fbef711a 100644
--- a/storage/federatedx/ha_federatedx.cc
+++ b/storage/federatedx/ha_federatedx.cc
@@ -319,6 +319,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "sql_analyse.h"                        // append_escaped()
 #include "sql_show.h"                           // append_identifier()
 #include "tztime.h"                             // my_tz_find()
+#include "sql_select.h"
 
 #ifdef I_AM_PARANOID
 #define MIN_PORT 1023
@@ -401,6 +402,12 @@ static void init_federated_psi_keys(void)
 #define init_federated_psi_keys() /* no-op */
 #endif /* HAVE_PSI_INTERFACE */
 
+handlerton* federatedx_hton;
+
+static derived_handler*
+create_federatedx_derived_handler(THD* thd, TABLE_LIST *derived);
+static select_handler*
+create_federatedx_select_handler(THD* thd, SELECT_LEX *sel);
 
 /*
   Initialize the federatedx handler.
@@ -418,7 +425,7 @@ int federatedx_db_init(void *p)
 {
   DBUG_ENTER("federatedx_db_init");
   init_federated_psi_keys();
-  handlerton *federatedx_hton= (handlerton *)p;
+  federatedx_hton= (handlerton *)p;
   federatedx_hton->state= SHOW_OPTION_YES;
   /* Needed to work with old .frm files */
   federatedx_hton->db_type= DB_TYPE_FEDERATED_DB;
@@ -432,6 +439,8 @@ int federatedx_db_init(void *p)
   federatedx_hton->discover_table_structure= ha_federatedx::discover_assisted;
   federatedx_hton->create= federatedx_create_handler;
   federatedx_hton->flags= HTON_ALTER_NOT_SUPPORTED;
+  federatedx_hton->create_derived= create_federatedx_derived_handler;
+  federatedx_hton->create_select= create_federatedx_select_handler;
 
   if (mysql_mutex_init(fe_key_mutex_federatedx,
                        &federatedx_mutex, MY_MUTEX_INIT_FAST))
@@ -3668,6 +3677,7 @@ err1:
   return error;
 }
 
+#include "federatedx_pushdown.cc"
 
 struct st_mysql_storage_engine federatedx_storage_engine=
 { MYSQL_HANDLERTON_INTERFACE_VERSION };
@@ -3689,3 +3699,4 @@ maria_declare_plugin(federatedx)
   MariaDB_PLUGIN_MATURITY_STABLE /* maturity */
 }
 maria_declare_plugin_end;
+
diff --git a/storage/federatedx/ha_federatedx.h b/storage/federatedx/ha_federatedx.h
index 16a1944b172..c6af5f257ef 100644
--- a/storage/federatedx/ha_federatedx.h
+++ b/storage/federatedx/ha_federatedx.h
@@ -1,3 +1,5 @@
+#ifndef HA_FEDERATEDX_INCLUDED
+#define HA_FEDERATEDX_INCLUDED
 /*
 Copyright (c) 2008, Patrick Galbraith
 All rights reserved.
@@ -445,6 +447,9 @@ public:
   int external_lock(THD *thd, int lock_type);
   int reset(void);
   int free_result(void);
+
+  friend class ha_federatedx_derived_handler;
+  friend class ha_federatedx_select_handler;
 };
 
 extern const char ident_quote_char;              // Character for quoting
@@ -460,3 +465,7 @@ extern federatedx_io *instantiate_io_mysql(MEM_ROOT *server_root,
                                            FEDERATEDX_SERVER *server);
 extern federatedx_io *instantiate_io_null(MEM_ROOT *server_root,
                                           FEDERATEDX_SERVER *server);
+
+#include "federatedx_pushdown.h"
+
+#endif /* HA_FEDERATEDX_INCLUDED */