Don't iterate over deleted keys in a transaction

[remcowesterhoud]

Description

When iterating in an open transaction, we would create an iterator containing all entries in the database as well as the entries in the transaction cache. This ensures any keys added in the same transaction are also encountered during iterating.

We do not do anything with the keys that are deleted within the transaction. As a result, when iterating we will go over keys that are already deleted. This is wrong. The keys are deleted, so we should not encounter them anymore during iterating.

Related issues

closes #876

Definition of Done

Not all items need to be done depending on the issue and the pull request.

Code changes:

• The changes are backwards compatibility with previous versions
• If it fixes a bug then PRs are created to backport the fix

Testing:

• There are unit/integration tests that verify all acceptance criterias of the issue
• New tests are written to ensure backwards compatibility with further versions
• The behavior is tested manually

Documentation:

• Javadoc has been written
• The documentation is updated

[github-actions]

Test Results

  47 files  ±0    47 suites  ±0   2m 10s ⏱️ -16s
102 tests +1  102 ✔️ +1  0 💤 ±0  0 ❌ ±0 
329 runs  +3  329 ✔️ +3  0 💤 ±0  0 ❌ ±0 

Results for commit 84be02b. ± Comparison against base commit a71a253.

[nicpuppa]

LGTM, nice one 🚀

[remcowesterhoud]

bors merge

[ghost]

Build succeeded:

• Test summary

[backport-action]

Validation Failed: {"resource":"Issue","code":"custom","message":"must be a collaborator"}

[backport-action]

Validation Failed: {"resource":"Issue","code":"custom","message":"must be a collaborator"}

[backport-action]

Validation Failed: {"resource":"Issue","code":"custom","message":"must be a collaborator"}

[ghost]

Already running a review

[remcowesterhoud]

/backport

[backport-action]

Git push to origin failed for stable/8.1 with exitcode 1

[backport-action]

Git push to origin failed for stable/8.2 with exitcode 1

[backport-action]

Git push to origin failed for stable/8.3 with exitcode 1

[backport-action]

Git push to origin failed for stable/8.1 with exitcode 1

[backport-action]

Git push to origin failed for stable/8.2 with exitcode 1

[backport-action]

Git push to origin failed for stable/8.3 with exitcode 1

[remcowesterhoud]

Manual backports

• Backport 876 stable/8.3 #932
• Backport 876 to stable/8.2 #933
• Backport 876 to stable/8.1 #934