Hi Ramin, Thank you for for driving this topic.
I have a couple of questions about this proposal： 1. Could we elaborate a bit more on when users would typically need this feature? It will be helpful to have a few concrete scenarios illustrating. 2. Since the proposal supports converting a CatalogTable to a CatalogMaterializedTable, should we also consider the reverse direction? I'd appreciate your thoughts on this. Kui.Yuan Ramin Gharib <[email protected]> 于2026年5月13日周三 18:57写道： > Hi everyone, > > I'd like to start a discussion on FLIP-578: In-place Table to Materialized > Table conversion. [1] > Flink's catalog DDL has no way to change a table's kind. Converting a > regular CREATE TABLE to a materialized table today requires creating a new > MT under a different name, repointing downstream consumers, and dropping > the old one — breaking references, doubling storage during cutover, and > offering no atomic rename. > > The FLIP proposes to allow CREATE OR ALTER MATERIALIZED TABLE > <existing_table> AS <query> against an existing regular table, converting > it in place. Identity and storage are preserved, and the conversion > surfaces as a distinct Operation subtype. > > Highlights: > 1. Gated by a new opt-in config option, > table.materialized-table.conversion-from-table.enabled (default false). > Existing workflows are unchanged. > 2. A new Catalog method convertTableToMaterializedTable(...) is added with > a default that throws UnsupportedOperationException, so existing catalogs > remain source- and binary-compatible. > 3. Validation reuses the existing ALTER MATERIALIZED TABLE machinery > (schema reconciliation, options merge, freshness / refresh-mode). The > CREATE OR ALTER keyword (FLIP-546 [2]) is idempotent and inherits FLIP-492 > query evolution for free. > > Looking forward to your feedback. > > Best, > Ramin Gharib [1] > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-578%3A+In-place+Table+to+Materialized+Table+conversion > [2] > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-546%3A+Introduce+CREATE+OR+ALTER+for+Materialized+Tables >
