core: warm key TransactionIndexTail by writing

[buddh0]

Description

core: warm key TransactionIndexTail by writing

Rationale

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Example

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Changes

Notable changes:

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[Copilot]

Pull Request Overview

This PR introduces a warm-up mechanism for the TransactionIndexTail key by performing a dummy write if the key exists in cold SST files, thereby optimizing future read performance.

• Removed the previous inline assignment for lastTail.
• Added a new code block to perform a dummy write using a batch operation if lastTail is non-nil.

[Copilot]

[nitpick] Consider extracting the warm-up write logic into a separate function for improved readability and maintainability in case this behavior needs to be reused or extended.

Suggested change

	lastTail := rawdb.ReadTxIndexTail(indexer.db)
	if lastTail != nil {
	// NOTE: The "TransactionIndexTail" key may exist only in cold SST files.
	// Without a recent write, the key won't be in the memtable or block cache,
	// causing every Get to trigger expensive readBlock + CRC checks.
	//
	// This dummy write forces the key into the memtable (and later SST),
	// ensuring future reads are fast (from memory or block cache).
	batch := indexer.db.NewBatch()
	rawdb.WriteTxIndexTail(batch, *lastTail)
	if err := batch.Write(); err != nil {
	log.Crit("Failed to write TransactionIndexTail warm-up", "error", err)
	return
	}
	lastTail := indexer.warmUpTxIndexTail()
	if lastTail == nil {
	return

[octavio12345300]

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