HHH-20050:- Create Spanner PostgreSQL dialect (Basic version) #11572

sakthivelmanii · 2026-01-08T20:44:46Z

[Please describe here what your change is about]

Created a basic version of Spanner version of Dialect

Fixed all the features that needs to be enabled / disbled
Added support for table creation without primary key
Added support for dropping indexes before dropping the table
Added support for sequences
Added support for creating unique index

Upcoming:

Add support for types
Add support for temporary tables
Add support for locking ..etc

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license
and can be relicensed under the terms of the LGPL v2.1 license in the future at the maintainers' discretion.
For more information on licensing, please check here.

https://hibernate.atlassian.net/browse/HHH-20050

...y-dialects/src/main/java/org/hibernate/community/dialect/SpannerPostgreSQLTableExporter.java

hibernate-core/src/main/java/org/hibernate/dialect/SpannerPostgreSQLDialect.java

beikov · 2026-01-09T12:28:20Z

...mmunity-dialects/src/main/java/org/hibernate/community/dialect/SpannerPostgreSQLDialect.java

+import org.hibernate.procedure.spi.CallableStatementSupport;
+import org.hibernate.tool.schema.internal.StandardTableExporter;
+
+public class SpannerPostgreSQLDialect extends PostgreSQLDialect {


With all the overrides here and potentially missed cases in the SqlAstTranslator I'm kind of starting to think that extending the PostgreSQLDialect is not a good idea.
The use of the Spanner JDBC driver in Database#SPANNER_PG also makes me think that it might be better to extend the SpannerDialect here and override the functions and DDL types or whatever is different from standard Spanner.
Finally, I would prefer to move this dialect to the hibernate-community-dialects project until we can figure out a way to regularly test it.

@beikov Spanner PG is more aligned(more closer) with PostgreSQL compared to Spanner dialect. I agree that we override lot of methods. We have plans on providing support for them so that we can get rid of these overriden methods. The current dialect shows the gist of what's different compared to OSS PG.

I am trying to onboard the dialect in phases so that it will be easy for review(though I have fixed all the tests in my local). I am planning to onboard testing in CI as soon as I make all changes related to the Dialect. Do you suggest we should move to community dialect first and later bring it to core once we configure the testing pipeline?

I am trying to onboard the dialect in phases so that it will be easy for review(though I have fixed all the tests in my local).

What do you mean by "fixed all the tests"? I would hope that we don't require many @SkipDialect uses.

I am planning to onboard testing in CI as soon as I make all changes related to the Dialect. Do you suggest we should move to community dialect first and later bring it to core once we configure the testing pipeline?

Yes please. Until we can properly and regularly test this new dialect, I would prefer to have it in the community dialects module.

@beikov

What do you mean by "fixed all the tests"? I would hope that we don't require many @SkipDialect uses.

Spanner doesn't support integer sequences due to it's nature as a distributed databases(to avoid hotspots). We might have to disable some tests which uses integer identity column(@id with Integer).

@beikov Thanks for the suggestions. I have moved the dialect to inside community dialect.

Spanner doesn't support integer sequences due to it's nature as a distributed databases(to avoid hotspots). We might have to disable some tests which uses integer identity column(@id with Integer).

Cockroach has a similar problem and solved it in the past by always emitting serial8 or int8 as column type. See CockroachDBIdentityColumnSupport

@beikov I think cockroach serial type has a capability to produce auto-incrementing sequences of int type(to avoid hotspots). In Spanner, serial type also produces Long values which can't fit into Integer type.

@sakthivelmanii this is fine for now, though it'll need to be addressed once we aim to set-up testing and move this into core.

hibernate-github-bot · 2026-01-09T14:06:17Z

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...y-dialects/src/main/java/org/hibernate/community/dialect/SpannerPostgreSQLTableExporter.java

sakthivelmanii · 2026-01-12T12:05:28Z

@beikov Can we merge this?

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/ColumnValue.java

sakthivelmanii · 2026-01-13T09:31:23Z

@beikov @gavinking can we please merge this if everything is okay?

gavinking

One very minor thing, but apart from that I have no further objection.

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/ColumnValue.java

sakthivelmanii · 2026-01-13T10:02:00Z

One very minor thing, but apart from that I have no further objection.

All the issues are fixed from my side. there was a bug when I moved dialect from core to community.

sakthivelmanii · 2026-01-13T14:58:33Z

@gavinking Can we merge this?

gavinking · 2026-01-13T15:43:17Z

Don't look at me, not my area.

sakthivelmanii · 2026-01-14T13:26:40Z

@beikov @mbellade Can you please help merging this PR?

mbellade · 2026-01-14T13:41:09Z

@sakthivelmanii static code analysis is failing, please run ./gradlew spotlessApply to fix it

sakthivelmanii · 2026-01-14T13:44:02Z

@mbellade Thanks. I have pushed the code again.

mbellade · 2026-01-14T13:45:13Z

Great, please squash everything to a single commit and we're good to go

sakthivelmanii · 2026-01-14T13:49:49Z

@mbellade Thanks. I have squashed into one commit.

sakthivelmanii · 2026-01-14T14:00:33Z

@mbellade It was failing with this error #11585. I rebased with the latest main branch

sakthivelmanii · 2026-01-14T14:51:10Z

@mbellade build is green. Jenkins CI (hibernate-orm-pipeline) is not approved.

sakthivelmanii force-pushed the create_spanner_postgresql_dialect branch from f653970 to 1d7bdc0 Compare January 8, 2026 20:52

beikov reviewed Jan 9, 2026

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HHH-20050:- Create Spanner PostgreSQL dialect

73598b6

sakthivelmanii force-pushed the create_spanner_postgresql_dialect branch from 1e39292 to 73598b6 Compare January 14, 2026 14:00

mbellade merged commit 4d75c7a into hibernate:main Jan 14, 2026
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HHH-20050:- Create Spanner PostgreSQL dialect (Basic version) #11572

HHH-20050:- Create Spanner PostgreSQL dialect (Basic version) #11572

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