Incremental Player Save

A mod to eliminate MSPT spikes caused by player data auto-save on Minecraft servers.

What It Does

Minecraft's auto-save calls net.minecraft.server.PlayerManager.saveAllPlayerData() once per save interval, writing every online player's data to disk in a single tick. On servers with many players or with a lot of player data, this can cause a large MSPT spike.

Incremental Player Save fixes this by spreading player saves across multiple ticks, saving a small batch of players per tick rather than all at once. This mod was inspired by Paper's incremental player saving feature.

Who This Is For

Install this mod if you see any of the following:

• Regular MSPT spikes every auto-save interval (default: every 6000 ticks / 5 minutes)
• net.minecraft.server.PlayerManager.saveAllPlayerData appearing in Spark profiler results during spikes

This mod targets only player .dat file writes. It will not reduce spikes from chunk saving or other auto-save work.

Configuration

All options are in the mod's config file in config/incrementalplayersave.json

Option	Description	Default
ticksBetweenSaveAttempts	How often (in ticks) the mod checks which players are due for a save	20
ticksBetweenSavesPerPlayer	Minimum ticks between saves for any individual player	6000
maxPlayersSavedPerAttempt	Maximum number of players saved per attempt. Controls per-tick save cost	3
enableDebugLog	Log save actions to console	false

Other Notes

• Some optimization mods may include similar functionality. Use Spark to confirm whether saveAllPlayerData still appears in your profiles before installing. On my server with many optimization mods like Lithium, none of them alleviated the tick spike caused by PlayerManager.saveAllPlayerData().

• net.minecraft.server.PlayerManager.saveAllPlayerData() is net.minecraft.server.players.PlayerList.saveAll() in Mojang Mappings.