CLX-14 This commit adds support for pushed conditions for table API.

mysql-test/suite/xpand/pushdown_conditions.result

+CREATE DATABASE xpd;
+USE xpd;
+DROP TABLE IF EXISTS cx1;
+CREATE TABLE cx1(i BIGINT, i2 BIGINT, t TEXT)ENGINE=xpand;
+INSERT INTO cx1 VALUES (41, 43, 'some1'), (42, 42, 'some2'), (43, 41, 'some3');
+SELECT * FROM cx1 ORDER BY i;
+i	i2	t
+41	43	some1
+42	42	some2
+43	41	some3
+SET xpand_select_handler=OFF;
+SELECT * FROM cx1 WHERE i>41 AND i2>41;
+i	i2	t
+42	42	some2
+EXPLAIN SELECT * FROM cx1 WHERE i>41 AND i2>41;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	cx1	ALL	NULL	NULL	NULL	NULL	10000	Using where with pushed condition
+SELECT * FROM cx1 WHERE i>41 AND i2>41 AND t='some2';
+i	i2	t
+42	42	some2
+EXPLAIN SELECT * FROM cx1 WHERE i>41 AND i2>41 AND t='some2';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	cx1	ALL	NULL	NULL	NULL	NULL	10000	Using where with pushed condition
+SELECT * FROM cx1 WHERE i>i2+1;
+i	i2	t
+43	41	some3
+EXPLAIN SELECT * FROM cx1 WHERE i>i2+1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	cx1	ALL	NULL	NULL	NULL	NULL	10000	Using where with pushed condition
+SET @@optimizer_switch='derived_merge=OFF';
+SELECT * FROM (SELECT * FROM cx1 WHERE i>i2+1) a1 ORDER BY i;
+i	i2	t
+43	41	some3
+EXPLAIN SELECT * FROM (SELECT * FROM cx1 WHERE i>i2+1) a1 ORDER BY i;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	10000	Using filesort
+2	PUSHED DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+SET xpand_derived_handler=OFF;
+SELECT * FROM (SELECT * FROM cx1 WHERE i>i2+1) a1 ORDER BY i;
+i	i2	t
+43	41	some3
+EXPLAIN SELECT * FROM (SELECT * FROM cx1 WHERE i>i2+1) a1 ORDER BY i;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	10000	Using filesort
+2	DERIVED	cx1	ALL	NULL	NULL	NULL	NULL	10000	Using where with pushed condition
+USE test;
+DROP DATABASE xpd;

mysql-test/suite/xpand/pushdown_conditions.test

+CREATE DATABASE xpd;
+USE xpd;
+
+--disable_warnings
+DROP TABLE IF EXISTS cx1;
+--enable_warnings
+CREATE TABLE cx1(i BIGINT, i2 BIGINT, t TEXT)ENGINE=xpand;
+
+INSERT INTO cx1 VALUES (41, 43, 'some1'), (42, 42, 'some2'), (43, 41, 'some3');
+
+SELECT * FROM cx1 ORDER BY i;
+SET xpand_select_handler=OFF;
+
+SELECT * FROM cx1 WHERE i>41 AND i2>41;
+EXPLAIN SELECT * FROM cx1 WHERE i>41 AND i2>41;
+SELECT * FROM cx1 WHERE i>41 AND i2>41 AND t='some2';
+EXPLAIN SELECT * FROM cx1 WHERE i>41 AND i2>41 AND t='some2';
+SELECT * FROM cx1 WHERE i>i2+1;
+EXPLAIN SELECT * FROM cx1 WHERE i>i2+1;
+
+# The plugin doesn't use pushdown conditions for DH as of 10.5.1
+# but it is worth to test memory leaks.
+SET @@optimizer_switch='derived_merge=OFF';
+SELECT * FROM (SELECT * FROM cx1 WHERE i>i2+1) a1 ORDER BY i;
+EXPLAIN SELECT * FROM (SELECT * FROM cx1 WHERE i>i2+1) a1 ORDER BY i;
+SET xpand_derived_handler=OFF;
+SELECT * FROM (SELECT * FROM cx1 WHERE i>i2+1) a1 ORDER BY i;
+EXPLAIN SELECT * FROM (SELECT * FROM cx1 WHERE i>i2+1) a1 ORDER BY i;
+
+# SELECT * FROM (SELECT i FROM cx1 WHERE i=42)a1,(SELECT i FROM cx1 WHERE i =42)a2 WHERE a1.i=a2.i;
+# EXPLAIN SELECT * FROM (SELECT i FROM cx1 WHERE i=42)a1,(SELECT i FROM cx1 WHERE i =42)a2 WHERE a1.i=a2.i;
+
+USE test;
+DROP DATABASE xpd;

storage/xpand/ha_xpand.cc

@@ -593,6 +593,7 @@ int ha_xpand::reset()
   upsert_flag &= ~XPAND_HAS_UPSERT;
   upsert_flag &= ~XPAND_UPSERT_SENT;
   xpd_lock_type = XPAND_NO_LOCKS;
+  pushdown_cond_list.empty();
   return 0;
 }
 
@@ -1079,8 +1080,25 @@ int ha_xpand::rnd_init(bool scan)
   bitmap_set_all(&scan_fields);
 #endif
 
+  String* pushdown_cond_sql = nullptr;
+  if (pushdown_cond_list.elements) {
+    pushdown_cond_sql = new String();
+    while (pushdown_cond_list.elements > 0) {
+      COND* cond = pushdown_cond_list.pop();
+      String sql_predicate;
+      cond->print_for_table_def(&sql_predicate);
+      pushdown_cond_sql->append(sql_predicate);
+      if ( pushdown_cond_list.elements > 0)
+        pushdown_cond_sql->append(" AND ");
+    }
+  }
+ 
   error_code = trx->scan_table(xpand_table_oid, xpd_lock_type, &scan_fields,
-                               THDVAR(thd, row_buffer), &scan_cur);
+                               THDVAR(thd, row_buffer), &scan_cur,
+                               pushdown_cond_sql);
+
+  if (pushdown_cond_sql != nullptr)
+    delete pushdown_cond_sql;
 
   if (error_code == HA_ERR_TABLE_DEF_CHANGED)
     xpand_mark_table_for_discovery(table);
@@ -1255,11 +1273,17 @@ int ha_xpand::external_lock(THD *thd, int lock_type)
 
 const COND *ha_xpand::cond_push(const COND *cond)
 {
-  return cond;
+  THD *thd= ha_thd();
+  if (!thd->lex->describe) {
+    pushdown_cond_list.push_front(const_cast<COND*>(cond));
+  }
+
+  return NULL;
 }
 
 void ha_xpand::cond_pop()
 {
+  pushdown_cond_list.pop();
 }
 
 int ha_xpand::info_push(uint info_type, void *info)

storage/xpand/ha_xpand.h

@@ -68,6 +68,8 @@ class ha_xpand : public handler
   } xpd_upsert_flags_t;
   int upsert_flag;
 
+  List<COND> pushdown_cond_list;
+
   Xpand_share *get_share(); ///< Get the share
 
 public:

storage/xpand/xpand_connection.cc

@@ -83,6 +83,7 @@ enum xpand_commands {
   XPAND_UPDATE_QUERY,
   XPAND_COMMIT,
   XPAND_ROLLBACK,
+  XPAND_SCAN_TABLE_COND,
 };
 
 /****************************************************************************
@@ -732,7 +733,8 @@ int xpand_connection::allocate_cursor(MYSQL *xpand_net, ulong buffer_size,
 int xpand_connection::scan_table(ulonglong xpand_table_oid,
                                  xpand_lock_mode_t lock_mode,
                                  MY_BITMAP *read_set, ushort row_req,
-                                 xpand_connection_cursor **scan)
+                                 xpand_connection_cursor **scan,
+                                 String* pushdown_cond_sql)
 {
   int error_code;
   command_length = 0;
@@ -741,8 +743,13 @@ int xpand_connection::scan_table(ulonglong xpand_table_oid,
   if (trans_flags & XPAND_TRANS_AUTOCOMMIT)
     return HA_ERR_INTERNAL_ERROR;
 
-  if ((error_code = begin_command(XPAND_SCAN_TABLE)))
+  if (pushdown_cond_sql != nullptr) {
+    if ((error_code= begin_command(XPAND_SCAN_TABLE_COND)))
+      return error_code;
+  } else {
+    if ((error_code= begin_command(XPAND_SCAN_TABLE)))
       return error_code;
+  }
 
   if ((error_code = add_command_operand_ushort(row_req)))
     return error_code;
@@ -756,6 +763,14 @@ int xpand_connection::scan_table(ulonglong xpand_table_oid,
   if ((error_code = add_command_operand_bitmap(read_set)))
     return error_code;
 
+  if (pushdown_cond_sql != nullptr) {
+    if ((error_code= add_command_operand_str(
+      reinterpret_cast<const uchar*>(pushdown_cond_sql->ptr()),
+      pushdown_cond_sql->length()))) {
+      return error_code;
+    }
+  }
+
   if ((error_code = send_command()))
     return error_code;
 

storage/xpand/xpand_connection.h

@@ -91,7 +91,7 @@ class xpand_connection
   int scan_table(ulonglong xpand_table_oid,
                  xpand_lock_mode_t lock_mode,
                  MY_BITMAP *read_set, ushort row_req,
-                 xpand_connection_cursor **scan);
+                 xpand_connection_cursor **scan, String* pushdown_cond_sql);
   int scan_query(String &stmt, uchar *fieldtype, uint fields, uchar *null_bits,
                  uint null_bits_size, uchar *field_metadata,
                  uint field_metadata_size, ushort row_req, ulonglong *oids,