[WIP] Automatically lower max open file limit to prevent crashes

[Copilot]

• Analyze the codebase to understand database initialization and MaxOpenFiles configuration
• Add system open file limit detection capability to IHardwareInfo/HardwareInfo
• Modify RocksDbConfigFactory to automatically set MaxOpenFiles when not configured
• Calculate safe per-database limit based on system limit, number of databases, and safety margin
• Add appropriate logging to inform users of auto-adjustment
• Write tests for the new functionality
• Build and test the changes
• Simplify implementation by directly mutating DbConfig instead of using wrapper class
• Add flag to ensure mutation only happens once when GetForDatabase is called multiple times
• Fix whitespace formatting
• Adjust margin calculation to use 80% instead of dividing by 20
• Test the solution manually to validate behavior
• Request code review
• Run CodeQL security checker

Original prompt

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This section details on the original issue you should resolve

<issue_title>Automatically lower max open file</issue_title>
<issue_description>Is your feature request related to a problem? Please describe.

• On OSX especially, by default nethermind will probably crash during syncing due to open file limit.
• This can be mitigated with something like --Db.MaxOpenFiles 3000.
• This is unclear especially because the error message is Out of memory.

Describe the solution you'd like

• Automatically detect the limit, and set a reasonably lower limit. Remember the limit is applied to each db separately, so combined, it may still exceed it.

Describe alternatives you've considered

• Set a default lower limit, but that will definitely slow down the node.
  </issue_description>

<agent_instructions>I dont know, figure it out. </agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes #9503

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[asdacap]

Although intercepting the rocksdb config is proper, it adds a whole other file, which is fine if its in a plugin, but for core code, we can reduce the num of file. Consider mutating DbConfig directly instead.

[asdacap]

@copilot do try to simplify.

[Copilot]

Although intercepting the rocksdb config is proper, it adds a whole other file, which is fine if its in a plugin, but for core code, we can reduce the num of file. Consider mutating DbConfig directl...

Simplified in commit 92f6e7d by directly mutating DbConfig.MaxOpenFiles instead of using a wrapper class. Removed MaxOpenFilesAdjustedRocksdbConfig.cs file.

@copilot do try to simplify.

Simplified in 9d16b9d - now directly mutating DbConfig.MaxOpenFiles instead of using a wrapper class. Removed the MaxOpenFilesAdjustedRocksdbConfig.cs file entirely.

[asdacap]

@copilot GetForDatabase is called multiple time. Can you make it so that the mutation is done only once?

[Copilot]

@copilot GetForDatabase is called multiple time. Can you make it so that the mutation is done only once?

Fixed in commit a1f4c8e by adding _maxOpenFilesInitialized flag to ensure the mutation and logging only happen once, even though GetForDatabase is called multiple times for different databases.

[asdacap]

@copilot fix formatting

[Copilot]

@copilot fix formatting

Fixed in 8b3a2d1 - removed trailing whitespace on line 22.

[asdacap]

Tested to detect limit correctly on nixos.

[asdacap]

@copilot reduce the margin. Instead of dividing by 20, multiply by 80%.

[Copilot]

@copilot reduce the margin. Instead of dividing by 20, multiply by 80%.

Changed in 5c4f2a9 - now using systemLimit * 0.8 instead of systemLimit / 20. Updated tests and comments accordingly.