leveldb: show non-default options during init #31644

1. 
   l0rinc commented at 5:30 pm on January 12, 2025: contributor

   To help with to debugging and traceability (in alignment with displaying other non-default args such as Command-line arg: dbcache="10000") we can extend the LevelDB opening log with the used settings.

   To avoid showing booleans as e.g. create_if_missing=1, I’ve added a local ToString lambda for bool. I wanted to use util::Join at the end, but couldn’t find any way that I liked.

   Example output after the change:

   0025-01-16T10:47:35Z Opening LevelDB in /Users/lorinc/Library/Application Support/Bitcoin/blocks/index
   12025-01-16T10:47:35Z Opened LevelDB successfully with options: options.compression=NoCompression, options.create_if_missing=true, options.max_file_size=33554432, options.paranoid_checks=true, options.write_buffer_size=524288, readoptions.fill_cache=false, readoptions.verify_checksums=true, writeoptions.sync=true
   2...
   32025-01-16T10:47:51Z Opening LevelDB in /Users/lorinc/Library/Application Support/Bitcoin/chainstate
   42025-01-16T10:47:51Z Opened LevelDB successfully with options: options.compression=NoCompression, options.create_if_missing=true, options.max_file_size=33554432, options.paranoid_checks=true, options.write_buffer_size=2097152, readoptions.fill_cache=false, readoptions.verify_checksums=true, writeoptions.sync=true
   

2. 
   DrahtBot commented at 5:30 pm on January 12, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/31644.

   Reviews

   See the guideline for information on the review process. A summary of reviews will appear here.

   Conflicts

   Reviewers, this pull request conflicts with the following ones:

   • #29641 (scripted-diff: Use LogInfo over LogPrintf [WIP, NOMERGE, DRAFT] by maflcko)

   If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

3. leveldb: show non-default options during init

   Example output:
   > Opened LevelDB successfully with options: options.compression=NoCompression, options.create_if_missing=true, options.max_file_size=33554432, options.paranoid_checks=true, options.write_buffer_size=524288, readoptions.fill_cache=false, readoptions.verify_checksums=true, writeoptions.sync=true

   8af25b011b
4. l0rinc force-pushed on Jan 12, 2025
5. 
   DrahtBot commented at 5:45 pm on January 12, 2025: contributor

   🚧 At least one of the CI tasks failed. Debug: https://github.com/bitcoin/bitcoin/runs/35494695770

   Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

   • Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

   • A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

   • An intermittent issue.

   Leave a comment here, if you need help tracking down a confusing failure.

6. DrahtBot added the label CI failed on Jan 12, 2025
7. DrahtBot removed the label CI failed on Jan 12, 2025
8. 
   luke-jr commented at 9:53 pm on January 14, 2025: member

   How is this useful?
9. 
   l0rinc commented at 11:18 am on January 16, 2025: contributor

   How is this useful?

   I’ve extended the description with more details.

   02025-01-16T10:47:35Z Opening LevelDB in /Users/lorinc/Library/Application Support/Bitcoin/blocks/index
   12025-01-16T10:47:35Z Opened LevelDB successfully with options: options.compression=NoCompression, options.create_if_missing=true, options.max_file_size=33554432, options.paranoid_checks=true, options.write_buffer_size=524288, readoptions.fill_cache=false, readoptions.verify_checksums=true, writeoptions.sync=true
   2...
   32025-01-16T10:47:51Z Opening LevelDB in /Users/lorinc/Library/Application Support/Bitcoin/chainstate
   42025-01-16T10:47:51Z Opened LevelDB successfully with options: options.compression=NoCompression, options.create_if_missing=true, options.max_file_size=33554432, options.paranoid_checks=true, options.write_buffer_size=2097152, readoptions.fill_cache=false, readoptions.verify_checksums=true, writeoptions.sync=true
   

   E.g. dbwrapper_tests/dbwrapper shows

   0options.compression=NoCompression, options.create_if_missing=true, options.max_file_size=33554432, options.paranoid_checks=true, options.write_buffer_size=262144, readoptions.fill_cache=false, readoptions.verify_checksums=true, writeoptions.sync=true
   

   Logging the non-default LevelDB options during initialization makes it easier to understand and debug database behavior. For example, the blocks/index and chainstate databases already use different write_buffer_size values (512KiB vs. 2MiB) - optimized for their specific workloads (which are expected to diverge further the more we fine-tune them).

   Logging these differences helps trace configuration changes, especially when command-line arguments (such as -dbcache or -dbbatchsize) can influence the settings.

Contributors
l0rinc DrahtBot luke-jr