[FLINK-20226] Temporal Table Functions cannot be created with a view reference

• Type: Bug
• Status: Open
• Priority: Not a Priority
• Resolution: Unresolved
• Affects Version/s: 1.12.0
• Component/s: Table SQL / API
• Labels: auto-deprioritized-major auto-deprioritized-minor
• Assignee: Unassigned
• Reporter: Benoît Paris
• Created: 18/Nov/20 19:09
• Updated: 26/Nov/21 10:39

Description

Temporal Table Functions fail to be created if the history side `Table` is obtained through `StreamTableEnvironment.from`.

With:

 

CREATE VIEW datagen_history_v AS
SELECT 
 f_random_str,
 COALESCE(ts, null) AS ts,
 f_random + 1 AS f_random
FROM datagen_history

 

This will create a Temporal Table Function that fail while being queried later on:

Table historyTable = tEnv.from("datagen_history_v");

TemporalTableFunction temporalTable = historyTable.createTemporalTableFunction( $("ts"), $("f_random_str"));
tEnv.registerFunction("datagen_ttf", temporalTable);

 

There is a simple workaround: If the view is obtained through a query referencing it, it will succeed later on:

 

Table historyTable = tEnv.sqlQuery("SELECT * FROM datagen_history_v");

TemporalTableFunction temporalTable = historyTable.createTemporalTableFunction( $("ts"), $("f_random_str"));
tEnv.registerFunction("datagen_ttf", temporalTable);

 

---

Included for reproduction: a pom.xml, one succeeding java case, one failing java case, and the associated failing stacktrace.

It seems to be that the view reference has been made physical as a side effect of the query; as opposed to still being a view reference when `from` has been used.

Calcite's `Relbuilder` will need an `ExpandingPreparingTable` that is a `QueryOperationCatalogViewTable`, and instead is getting a `SqlCatalogViewTable`.

Now, as to knowing where and how the runtime could operate that conversion, I wouldn't know.