News

This page collects news and announcements about the development of Secondo. For a structured list of the changes per release, see the Release Notes.

26.06.2026 – Optimizer Integration

The SECONDO Optimizer has now been integrated into the SECONDO kernel, functioning as a first-class component. As a result, the OptServer has been removed, along with the old hybrid SECONDO binaries such as SecondoPLTTY, SecondoPLTTYCS, and SecondoPLTTYNT. The standard SECONDO binaries now support the optimizer and can be used for all applications. Additionally, the Java GUI has been adapted to work with the new optimizer interface. The option for custom optimizer connection settings has been removed.

SQL Queries like select count(*) from plz as p where [p:plz > 40000]; are directly supported by SecondoTTYBDB and SecondoTTYCS. By prefixing a query with optimize, the optimizer returns the best plan for the query.

Using showOptions();, setOption(xxx);, and delOption(xxx);, the user can configure the optimizer. By executing updateCatalog();, the knowledge base of the optimizer is updated.

19.06.2026 – Project Improvements

During the last days, the network, process management, and BDB stack of Secondo was improved:

Support for newer distributions
- Ubuntu 26.04 is supported.
- OS X 15 / 26 are supported.
  - No OS X SDK is needed anymore; Secondo now natively compiles on OS X.
  - The self-test for OS X is fixed and passes now.
  - Support for the Apple Silicon architecture was improved. BDB page sizes are now stable across different CPU architectures.
- A lot of logic/memory bugs were removed to support the newer compilers.
- .y files are updated to work with newer Yacc versions.
- The Debian package building infrastructure has been renovated, and packages for Ubuntu 22.04/24.04/26.04 are available.
- New auto-detection script $SECONDO_BUILD_DIR/CM-Scripts/secondo-detect.sh to determine the environment automatically.
- The installation instructions are rewritten entirely.
- Note: nlohmann-json3 is now a new installation dependency. Secondo now uses the distribution version of the library instead of a vendored version.
Improved build times
- Parallel make -j .. was repaired.
- make can now build algebras concurrently (so far, each algebra was built sequentially, with concurrent support for the files of the algebra).
- .java files are now compiled with one javac call instead of compiling each file individually.
- .dep files are generated by the main compiler run, no need for a second compiler pass on each .cpp file.
- ccache is now supported for caching build artifacts.
CI Improvements
- The OptServer is now tested in CI.
- Secondo could handle more than 25 parallel clients (verified by CI).
- The CI now builds also on OS X.
- A GitHub workflow is used now to build the .deb packages.
Stability
- All mallocs in the signal handlers are removed; crashing processes now crash and do not deadlock.
- In the server mode, processes have the ability to terminate gracefully instead of being killed by signal handlers right in BDB code.
- A lot of bugs in the BDB usage were removed:
  - Modified pages are marked as dirty.
  - Custom file usage tracking removed.
  - Cursor leaks are fixed.
  - Errors are propagated.
  - Race conditions are eliminated.
  - Deadlocks on catalog access are removed by using the proper tx context.
  - The BDB now refuses to start when not all components are initialized properly.
- Network sockets are hardened:
  - No lingering for faster server shutdowns.
  - Keepalive is set to detect gone clients.
  - OS return codes are honored properly.
  - Failing operations are retried if needed.
  - Errors are classified, and a lot of potential 100% CPU spin loops in the error case are removed.
- The SecondoRegistrar now uses a modern poll() based infrastructure. Multiple clients can be served; one blocking client can no longer stall the entire connection handling.
- The SecondoMonitor now monitors subprocesses – crashes are directly reported.
- Show log in the monitor now works and uses a bounded log buffer.
- The SecondoCheckpoint checks now periodically for lock pressure; a lock shortage will be reported.
- Subprocesses are properly terminated when their parent dies (e.g., CTRL+C cannot be used to terminate the monitor, all connections, and processes).
- Shutdown logic now distributes signals properly to child processes and gives them a chance to terminate.
- Use sigaction instead of signal to have a predictable contract.
- Use close_range when possible to free parent fd's. Saves ~524288 syscalls/550ms CPU time per network connection.
Misc
- Introduce SECONDO_NO_SIGNAL_HANDLERS to be able to skip Secondo's custom signal/crash handlers to get proper core dumps.
- Removed unused readline environment variable.
- .deb packages are now hosted by GitHub.

11.02.2022 – Development migrated to git/GitHub

So far, Secondo was developed in a self-hosted CVS repository. This project here was only a read-only mirror of the CVS repository. We have now completed the migration to git, and this repository is used for the development.

03.09.2021 – SECONDO 4.3.0 released

We are happy to announce the release of Secondo 4.3.0. See the Release Notes for more information.

23.08.2021 – Parallel building

The current version of Secondo supports the parallelization of the building process (e.g., make -j 32). This allows to build Secondo much faster. We measured a building time of 13 minutes (parallel) vs. 71 minutes (sequential) on our test system.

01.08.2021 – Debian 11 is supported

We are happy to announce that Debian 11 is now supported by Secondo.

10.03.2021 – M1 (ARM64) based Apple computers are now a supported platform

Secondo now supports Apple computers with an M1 (ARM64) CPU as platform. See the Install Guide for more information. Please note that no manual download of the BerkeleyDB or SWI-Prolog is required anymore. All dependencies on macOS are now managed by Homebrew.

20.01.2021 – Ubuntu 20.10 is supported

We are happy to announce that Ubuntu 20.10 is now supported by Secondo. The source code can now be built by gcc 10 and SWI-Prolog 8.2 is supported.

18.12.2020 – SECONDO source code available on GitHub

The Secondo source code is available on GitHub. The repository was originally a read-only mirror of the CVS repository; the project has since retired CVS and switched completely to this repository.

11.12.2020 – New article about debugging SECONDO on macOS

A new article about the debugging of Secondo on macOS is available.

03.12.2020 – Website is available on GitHub

The website of the project is now available on https://secondo-database.github.io/.

15.11.2020 – macOS 11 Big Sur – SECONDO SDK available

An SDK for macOS 11 (Big Sur) is now available for download.

01.10.2020 – Bison 3.0 deprecation warnings

All Bison 3.0 deprecation warnings (warning: deprecated directive) are fixed in the current version of the software.

24.09.2020 – C++17

We have changed the used C++ standard in the project to C++17. This means that you can use these new language features in your code. Please note that you have to run make clean to re-build the complete project.

23.09.2020 – Removal of the '-D_GLIBCPP_DEPRECATED' compiler flag

Until now, Secondo was built with the flag -D_GLIBCPP_DEPRECATED to get access to some deprecated functions in the glibc. The code base was updated and these functions are not used anymore. Therefore, the compiler flag was removed.

22.09.2020 – Build server is upgraded to openSUSE Leap 15.2

We have successfully upgraded the build- and CVS-server to openSUSE Leap 15.2; the system is now up and running.

Last Changed: 2026-07-21 (JNI)