Rails 8.1 support #2480

andynu · 2025-10-23T20:10:03Z

This PR brings full Rails 8.1 compatibility to the Oracle Enhanced adapter, building on excellent work by @akostadinov (Aleksandar N. Kostadinov) in PR #2471.

I've added only two additional fixes:

CLOB insertion with disabled prepared statements,
removal of the obsolete ExplainSubscriber reference that Rails 8.1 refactored away.

Credits

The vast majority of this work was done by Aleksandar N. Kostadinov (@akostadinov) and Daria Mayorova (@mayorova). Their comprehensive compatibility updates fixed nearly all Rails 8.1 issues.

Changes from @akostadinov's PR #2471

Core Rails 8.1 API Compatibility

Column constructor signature change (Eliminate queries loading dumped model schema on Postgres rails/rails#54333)
- Updated OracleEnhanced::Column.new to accept cast_type as second parameter
- Modified schema_statements.rb and schema_creation.rb to call lookup_cast_type and pass cast types to column
  constructors
- Updated tests to use new column constructor signature
Schema dumping method rename
- Changed dump_schema_information → dump_schema_versions throughout codebase
- Updated method calls and comments in schema_statements.rb and test specs
Native database types refactoring
- Moved native_database_types to class method to support Rails 8.1's static type resolution
- Instance method now delegates to class method
- Maintains backward compatibility with emulate_booleans_from_strings setting
Distinct column API changes (by @mayorova)
- Updated distinct_relation_for_primary_key to use Rails 7.1+ distinct column API
- Changed internal method call from previous API to distinct(column_name)

Test Infrastructure & Coverage

Rails 7.1 composite primary key tests
- Added comprehensive test suite for composite primary keys (composite_spec.rb)
- Tests unique constraints, validations, and composite key behavior
- 84 lines of new test coverage
Test reliability improvements
- Fixed emulate_booleans test to properly clear type map and re-establish connections
- Changed from instance variable @conn to leased connections for thread safety
- Added proper connection cleanup in test teardown
Schema enhancement follow-up (Remove `OracleEnhancedAdapter.default_tablespaces[native_database_typ… #1544)
- Updated create_sequence call to use proper keyword arguments
- Modernized sequence creation syntax

My Contributions (this PR)

CLOB Insertion Fix

Fixed CLOB/BLOB insertion when prepared_statements: false (commit 0a4ad58)
- Added before_create and after_create callbacks to LOB module
- Previously only had after_update callbacks, causing data loss on insert
- When prepared_statements is disabled, SQL uses empty_clob()/empty_blob() literals
- Now properly writes LOB data after record creation
- Added 51 lines of test coverage in type/text_spec.rb
- Fixes CLOB/BLOB Inserts Fail When prepared_statements: false (which happens when config.active_record.query_log_tags_enabled = true) #2477
- Uses ROWID for clob update statements to avoid issues with missing primary keys and/or composite primary keys. (e4b0156)

Rails 8.1 ExplainSubscriber Removal

Removed obsolete ActiveRecord::ExplainSubscriber reference (commit 85618af)
- Rails 8.1 removed ExplainSubscriber class
  (rails/rails@f488878)
- ExplainSubscriber functionality refactored into ExplainRegistry with lazy subscription
- Rails 8.1 now subscribes only when .explain is first called
- Removed manual subscription line from spec_helper.rb that was causing NameError

Testing

All tests pass against Rails 8.1 (8-1-stable branch).

yahonda · 2025-12-09T12:10:46Z

Would you drop these commits from this pull request? They should be for 8.0, not 8.1.

f34d8d6
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andynu · 2025-12-09T14:55:25Z

Certainly. Dropped.

Add after_create callbacks to LOB module to handle CLOB/BLOB writing when using empty_clob()/empty_blob() placeholders in INSERT statements. Previously, the LOB module only had after_update callbacks, causing CLOB data to be lost when records were created with prepared_statements disabled (which generates SQL with empty_clob() literals instead of bind parameters). Changes: - Add before_create :record_lobs_for_create callback - Add after_create :enhanced_write_lobs callback - Add record_lobs_for_create method to track non-nil LOB columns on create - Add tests for CLOB creation with prepared_statements disabled This fixes the issue where CLOBs would be empty after creation in environments where prepared_statements defaults to false. Issue rsim#2477

Rails 8.1 removed the ExplainSubscriber class (commit f488878f1bc), causing test failures with: NameError: uninitialized constant ActiveRecord::ExplainSubscriber The ExplainSubscriber functionality was refactored into ExplainRegistry with lazy subscription - instead of subscribing at initialization, Rails 8.1 now subscribes only when .explain is first called via ExplainRegistry.start. The spec_helper.rb line that manually subscribed to ExplainSubscriber is no longer needed or valid. Rails 8.1 handles the subscription automatically and lazily. Related Rails commit: - f488878f1bc "Refactor ExplainRegistry to only be subscribed once used" - Author: Jean Boussier - Date: Thu Sep 25 10:37:09 2025 +0200 - Link: rails/rails@f488878

Switch from pre-release alpha constraint to stable release constraint for ActiveRecord 8.1.0 dependency, following Rails 8.1 stable release.

Document Rails 8.1 support with installation instructions, including the gem version constraint for activerecord-oracle_enhanced-adapter 8.1.

Add ability to write LOB data to tables that don't have a primary key by: 1. Exposing cursor.rowid method in OCI connection wrapper 2. Capturing ROWID after INSERT in exec_insert (@last_insert_rowid) 3. Using ROWID in write_lobs WHERE clause when no PK is available 4. Supporting composite primary keys (Array) in write_lobs The ROWID approach works because: - Ruby-oci8's cursor.rowid returns the ROWID of the last inserted row - ROWID uniquely identifies any row regardless of table structure - The after_create callback fires immediately after INSERT on same connection Also includes ORA-01741 diagnostic logging for empty column detection.

andynu · 2025-12-09T15:34:06Z

Better. Rather than dropping, I just rebased this on top of master again. Since those commits were from earlier.

akostadinov · 2025-12-21T17:31:36Z

Amazing work @andynu!

I just want to point your attention also to #2483 as a big improvement of performance and memory usage for workloads involving LOBs. Basically I remove this write_lobs stuff altogether because it is completely redundant. This also allows much more efficient LOB reading from the server. IDK if you would want to amend your LOB fixes or maybe it can be merged/discussed further after this PR is merged. But wanted to point out to you. Or if you prefer I can create a pull request to your branch with it. Will be happy to get your feedback in either case.

…ents This spec clearly demonstrates the critical difference between LOB handling with prepared statements (bind parameters) vs without (raw SQL with empty_clob()). Key points demonstrated: - With prepared_statements: true, LOB data flows through type_cast() which creates OCI8::CLOB temp LOBs. Data is populated BEFORE INSERT. - With prepared_statements: false, SQL contains empty_clob() literals. The write_lobs callback is REQUIRED to populate LOB data after INSERT. This test suite will FAIL if the lob.rb callbacks are removed, proving they are necessary for backwards compatibility with prepared_statements: false. Related to: rsim#2483

When prepared_statements is enabled (the default), LOB data is already written during INSERT via temporary LOB binding in type_cast(). The write_lobs callback was redundantly writing the same data again via SELECT FOR UPDATE. This change skips the callback in the prepared statements path while preserving it for the unprepared path, where empty_clob()/empty_blob() literals require the callback to populate LOB data after INSERT. Fixes the double-write issue identified in rsim#2483.

akostadinov · 2025-12-30T16:23:06Z

lib/active_record/connection_adapters/oracle_enhanced/lob.rb

          # After setting large objects to empty, select the OCI8::LOB
          # and write back the data.
+          before_create :record_lobs_for_create
+          after_create :enhanced_write_lobs


For create, shouldn't it just write all non-empty and non-null lobs instead of tracking them?

But anyway, I think this LOB callback writing stuff needs to go unless there are non-easily adaptable use-cases for disabling prepared statements as discussed in #2483

P.S. adding this here, doesn't it mean write_lobs was not used for a long time on create already? And that people just use prepared statements and don't need this?

andynu force-pushed the rails-8-1-support branch from f942020 to e834b46 Compare October 23, 2025 21:16

andynu force-pushed the rails-8-1-support branch 2 times, most recently from 72a17f3 to e4b0156 Compare December 2, 2025 19:29

andynu added the dependencies Pull requests that update a dependency file label Dec 3, 2025

This was referenced Dec 3, 2025

Fix CLOB/BLOB insert failure when prepared_statements disabled (release80) #2479

Closed

Fix CLOB/BLOB insert failure when prepared_statements disabled (master) #2478

Closed

andynu force-pushed the rails-8-1-support branch from e4b0156 to 29a404c Compare December 9, 2025 14:52

andynu force-pushed the rails-8-1-support branch 2 times, most recently from 43de9c7 to e458c74 Compare December 9, 2025 15:26

andynu and others added 14 commits December 9, 2025 10:29

Switch to Rails 8.1 (8-1-stable branch) for compatibility testing

b45baa5

just a bit of troubleshooting info

7cbb567

Rails 8.1 API compatibility with rails/rails#54333

da3f6d4

activerecord 7.1 distinct column api change

3c15a11

test rails 7.1 composite indices

fb3bc00

follow through on rsim#1544

3b47d19

Rails compat - #native_database_types

48674a3

Rails #dump_schema_information -> #dump_schema_versions

fe2c703

emulate_booleans test reliable on newer Rails

9a2bc5a

Update ActiveRecord dependency to stable 8.1.0 release

b3b4969

Switch from pre-release alpha constraint to stable release constraint for ActiveRecord 8.1.0 dependency, following Rails 8.1 stable release.

Add Rails 8.1 installation section to README

3b56a8e

Document Rails 8.1 support with installation instructions, including the gem version constraint for activerecord-oracle_enhanced-adapter 8.1.

andynu force-pushed the rails-8-1-support branch from e458c74 to e3e858a Compare December 9, 2025 15:29

This was referenced Dec 16, 2025

Preliminary Rails 8.1 support #2471

Closed

No double writing of lobs #2483

Open

andynu added 2 commits December 27, 2025 14:45

akostadinov reviewed Dec 30, 2025

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Rails 8.1 support #2480

Rails 8.1 support #2480

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andynu commented Oct 23, 2025 •

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Credits

Changes from @akostadinov's PR #2471

My Contributions (this PR)

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