infoschema: show information about table partitions in information_schema.PARTITIONS

infoschema/tables.go

@@ -1785,6 +1785,107 @@ func dataForPseudoProfiling() [][]types.Datum {
 	return rows
 }
 
+func dataForPartitions(ctx sessionctx.Context, schemas []*model.DBInfo) ([][]types.Datum, error) {
+	tableRowsMap, colLengthMap, err := tableStatsCache.get(ctx)
+	if err != nil {
+		return nil, err
+	}
+	checker := privilege.GetPrivilegeManager(ctx)
+	var rows [][]types.Datum
+	createTimeTp := partitionsCols[18].tp
+	for _, schema := range schemas {
+		for _, table := range schema.Tables {
+			if checker != nil && !checker.RequestVerification(ctx.GetSessionVars().ActiveRoles, schema.Name.L, table.Name.L, "", mysql.SelectPriv) {
+				continue
+			}
+			createTime := types.NewTime(types.FromGoTime(table.GetUpdateTime()), createTimeTp, types.DefaultFsp)
+
+			var rowCount, dataLength, indexLength uint64
+			if table.GetPartitionInfo() == nil {
+				rowCount = tableRowsMap[table.ID]
+				dataLength, indexLength = getDataAndIndexLength(table, table.ID, rowCount, colLengthMap)
+				avgRowLength := uint64(0)
+				if rowCount != 0 {
+					avgRowLength = dataLength / rowCount
+				}
+				record := types.MakeDatums(
+					catalogVal,    // TABLE_CATALOG
+					schema.Name.O, // TABLE_SCHEMA
+					table.Name.O,  // TABLE_NAME
+					nil,           // PARTITION_NAME
+					nil,           // SUBPARTITION_NAME
+					nil,           // PARTITION_ORDINAL_POSITION
+					nil,           // SUBPARTITION_ORDINAL_POSITION
+					nil,           // PARTITION_METHOD
+					nil,           // SUBPARTITION_METHOD
+					nil,           // PARTITION_EXPRESSION
+					nil,           // SUBPARTITION_EXPRESSION
+					nil,           // PARTITION_DESCRIPTION
+					rowCount,      // TABLE_ROWS
+					avgRowLength,  // AVG_ROW_LENGTH
+					dataLength,    // DATA_LENGTH
+					nil,           // MAX_DATA_LENGTH
+					indexLength,   // INDEX_LENGTH
+					nil,           // DATA_FREE
+					createTime,    // CREATE_TIME
+					nil,           // UPDATE_TIME
+					nil,           // CHECK_TIME
+					nil,           // CHECKSUM
+					nil,           // PARTITION_COMMENT
+					nil,           // NODEGROUP
+					nil,           // TABLESPACE_NAME
+				)
+				rows = append(rows, record)
+			} else {
+				for i, pi := range table.GetPartitionInfo().Definitions {
+					rowCount = tableRowsMap[pi.ID]
+					dataLength, indexLength = getDataAndIndexLength(table, pi.ID, tableRowsMap[pi.ID], colLengthMap)
+
+					avgRowLength := uint64(0)
+					if rowCount != 0 {
+						avgRowLength = dataLength / rowCount
+					}
+
+					var partitionDesc string
+					if table.Partition.Type == 1 {
+						partitionDesc = pi.LessThan[0]
+					}
+
+					record := types.MakeDatums(
+						catalogVal,                    // TABLE_CATALOG
+						schema.Name.O,                 // TABLE_SCHEMA
+						table.Name.O,                  // TABLE_NAME
+						pi.Name.O,                     // PARTITION_NAME
+						nil,                           // SUBPARTITION_NAME
+						i+1,                           // PARTITION_ORDINAL_POSITION
+						nil,                           // SUBPARTITION_ORDINAL_POSITION
+						table.Partition.Type.String(), // PARTITION_METHOD
+						nil,                           // SUBPARTITION_METHOD
+						table.Partition.Expr,          // PARTITION_EXPRESSION
+						nil,                           // SUBPARTITION_EXPRESSION
+						partitionDesc,                 // PARTITION_DESCRIPTION
+						rowCount,                      // TABLE_ROWS
+						avgRowLength,                  // AVG_ROW_LENGTH
+						dataLength,                    // DATA_LENGTH
+						uint64(0),                     // MAX_DATA_LENGTH
+						indexLength,                   // INDEX_LENGTH
+						uint64(0),                     // DATA_FREE
+						createTime,                    // CREATE_TIME
+						nil,                           // UPDATE_TIME
+						nil,                           // CHECK_TIME
+						nil,                           // CHECKSUM
+						pi.Comment,                    // PARTITION_COMMENT
+						nil,                           // NODEGROUP
+						nil,                           // TABLESPACE_NAME
+					)
+					rows = append(rows, record)
+				}
+			}
+		}
+	}
+	return rows, nil
+}
+
 func dataForKeyColumnUsage(ctx sessionctx.Context, schemas []*model.DBInfo) [][]types.Datum {
 	checker := privilege.GetPrivilegeManager(ctx)
 	rows := make([][]types.Datum, 0, len(schemas)) // The capacity is not accurate, but it is not a big problem.
@@ -2292,6 +2393,7 @@ func (it *infoschemaTable) getRows(ctx sessionctx.Context, cols []*table.Column)
 			fullRows = dataForPseudoProfiling()
 		}
 	case tablePartitions:
+		fullRows, err = dataForPartitions(ctx, dbs)
 	case tableKeyColumn:
 		fullRows = dataForKeyColumnUsage(ctx, dbs)
 	case tableReferConst:

infoschema/tables_test.go

@@ -1079,3 +1079,54 @@ func (s *testTableSuite) TestSelectHiddenColumn(c *C) {
 	colInfo[2].Hidden = true
 	tk.MustQuery("select count(*) from INFORMATION_SCHEMA.COLUMNS where table_name = 'hidden'").Check(testkit.Rows("0"))
 }
+
+func (s *testTableSuite) TestPartitionsTable(c *C) {
+	s.dom.SetStatsUpdating(true)
+	oldExpiryTime := infoschema.TableStatsCacheExpiry
+	infoschema.TableStatsCacheExpiry = 0
+	defer func() { infoschema.TableStatsCacheExpiry = oldExpiryTime }()
+
+	do := s.dom
+	h := do.StatsHandle()
+	h.Clear()
+	is := do.InfoSchema()
+
+	tk := testkit.NewTestKit(c, s.store)
+
+	tk.MustExec("USE test;")
+	tk.MustExec("DROP TABLE IF EXISTS `test_partitions`;")
+	tk.MustExec(`CREATE TABLE test_partitions (a int, b int, c varchar(5), primary key(a), index idx(c)) PARTITION BY RANGE (a) (PARTITION p0 VALUES LESS THAN (6), PARTITION p1 VALUES LESS THAN (11), PARTITION p2 VALUES LESS THAN (16));`)
+	h.HandleDDLEvent(<-h.DDLEventCh())
+	tk.MustExec(`insert into test_partitions(a, b, c) values(1, 2, "c"), (7, 3, "d"), (12, 4, "e");`)
+
+	tk.MustQuery("select PARTITION_NAME, PARTITION_DESCRIPTION from information_schema.PARTITIONS where table_name='test_partitions';").Check(
+		testkit.Rows("" +
+			"p0 6]\n" +
+			"[p1 11]\n" +
+			"[p2 16"))
+
+	tk.MustQuery("select table_rows, avg_row_length, data_length, index_length from information_schema.PARTITIONS where table_name='test_partitions';").Check(
+		testkit.Rows("" +
+			"0 0 0 0]\n" +
+			"[0 0 0 0]\n" +
+			"[0 0 0 0"))
+	c.Assert(h.DumpStatsDeltaToKV(handle.DumpAll), IsNil)
+	c.Assert(h.Update(is), IsNil)
+	tk.MustQuery("select table_rows, avg_row_length, data_length, index_length from information_schema.PARTITIONS where table_name='test_partitions';").Check(
+		testkit.Rows("" +
+			"1 18 18 2]\n" +
+			"[1 18 18 2]\n" +
+			"[1 18 18 2"))
+
+	// Test for table has no partitions.
+	tk.MustExec("DROP TABLE IF EXISTS `test_partitions_1`;")
+	tk.MustExec(`CREATE TABLE test_partitions_1 (a int, b int, c varchar(5), primary key(a), index idx(c));`)
+	h.HandleDDLEvent(<-h.DDLEventCh())
+	tk.MustExec(`insert into test_partitions_1(a, b, c) values(1, 2, "c"), (7, 3, "d"), (12, 4, "e");`)
+	c.Assert(h.DumpStatsDeltaToKV(handle.DumpAll), IsNil)
+	c.Assert(h.Update(is), IsNil)
+	tk.MustQuery("select PARTITION_NAME, TABLE_ROWS, AVG_ROW_LENGTH, DATA_LENGTH, INDEX_LENGTH from information_schema.PARTITIONS where table_name='test_partitions_1';").Check(
+		testkit.Rows("<nil> 3 18 54 6"))
+
+	tk.MustExec("DROP TABLE `test_partitions`;")
+}