Struct LastFileReader 

pub struct LastFileReader<F: LogFileAccess> { /* private fields */ }

Tracks the last occurrence of specific log entry types.

Used during recovery to find checkpoint entries, etc.

Implementations

impl<F: LogFileAccess> LastFileReader<F>

pub fn new(file_access: F, read_buffer_size: usize) -> Result<Self>

Create a LastFileReader.

Automatically positions at the last good file with a complete header.

Arguments

• file_access - File I/O interface
• read_buffer_size - Size of read buffer

pub fn set_target_type(&mut self, entry_type: u8)

Register an entry type to track.

When entries of this type are encountered, their LSN will be recorded.

pub fn set_halt_on_commit_after_checksum(&mut self, halt: bool)

Enable/disable halt-on-committed-txn-after-checksum behavior.

Recovery wires this from the config param noxu.haltOnCommitAfterChecksumException (HALT_ON_COMMIT_AFTER_CHECKSUMEXCEPTION). When enabled, a checksum failure during end-of-log discovery triggers a forward scan for a TxnCommit entry; if one is found, read_next_entry returns the fatal NoxuLogError::FoundCommittedTxn rather than silently truncating.

Faithful to JE LastFileReader.readNextEntry (LastFileReader.java:313).

pub fn get_last_seen(&self, entry_type: u8) -> Lsn

Get the last LSN seen for a tracked entry type.

Returns NULL_LSN if the type was not seen.

pub fn get_end_of_log(&self) -> Lsn

Get the end-of-log LSN.

This is the LSN to use for the next log entry.

pub fn get_last_valid_lsn(&self) -> Lsn

Get the last valid LSN.

This is the LSN of the last successfully validated entry.

pub fn get_prev_offset(&self) -> u64

Get the previous offset from the last entry.

pub fn get_entry_type(&self) -> u8

Get the type of the last entry processed.

pub fn read_next_entry(&mut self) -> Result<bool>

Read the next entry.

This method stops at bad entries (checksum failures) and reports them as the end of the log, rather than throwing an error.

Returns Ok(true) if an entry was read, Ok(false) at end.