evaluated and simply selecting a column does not trigger the computation but it returns a Column Expression instance. [15]: from pyflink.table.expressions import col type(table.id)==type(col('id')) [15]: Expressions can be used to select the columns from a Table. For example, Table.select() takes the column Expression instances that returns another Table. [16]: table.select(table.id).to_pandas() [16]: id 0 1 1 1 2 [17]: table.select(col('id')).to_pandas() [17]: id 0 1 1 2 Assign new Column Expression instance. [18]: table.add_columns(col('data').upper_case.alias('upper_data')).to_pandas() [18]: id data

evaluated and simply selecting a column does not trigger the computation but it returns a Column Expression instance. [15]: from pyflink.table.expressions import col type(table.id)==type(col('id')) [15]: Expressions can be used to select the columns from a Table. For example, Table.select() takes the column Expression instances that returns another Table. [16]: table.select(table.id).to_pandas() [16]: id 0 1 1 1 2 [17]: table.select(col('id')).to_pandas() [17]: id 0 1 1 2 Assign new Column Expression instance. [18]: table.add_columns(col('data').upper_case.alias('upper_data')).to_pandas() [18]: id data

print()
 env.execute("Compute max sensor temperature”)
 }
 } Flink programs are defined in regular Scala/Java methods Set up the execution environment: local, cluster, I/O, time semantics,

State backends 7 Vasiliki Kalavri | Boston University 2020 MemoryStateBackend • Stores state as regular objects on TaskManager’s heap • Low read/write latencies • OutOfMemoryError if large grows too large

parameters either continuously or by running the system for a designated period of time, prior to regular query execution. 10 ??? Vasiliki Kalavri | Boston University 2020 Estimating cost and selectivity

acknowledges the checkpoint to the JobManager. After all barriers are sent out, the source continues its regular operations. ??? Vasiliki Kalavri | Boston University 2020 46 • When a task receives a checkpoint