[MC-147854] Frequent lag spikes (that seem to happen after playing in a single world long enough)

Lag spikes became increasingly common as I played in a world, until the game temporarily froze every second. I crashed the game while there was a lag spike in this crash report. The countdown messages didn't even appear when the game was freezing.

---- Minecraft Crash Report ----
// Surprise! Haha. Well, this is awkward.

Time: 4/10/19 8:23 PM
Description: Manually triggered debug crash

java.lang.Throwable
	at cuz.b(SourceFile:528)
	at cva.n(SourceFile:1466)
	at cva.d(SourceFile:917)
	at cva.b(SourceFile:410)
	at net.minecraft.client.main.Main.main(SourceFile:154)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Client thread
Stacktrace:
	at cuz.b(SourceFile:528)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [djm['gaspoweredpick'/209, l='MpServer', x=-23031.01, y=69.00, z=-19159.89]]
	Chunk stats: MultiplayerChunkCache: 729, 469
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: {}
	Level spawn location: World: (28,65,13), Chunk: (at 12,4,13 in 1,0; contains blocks 16,0,0 to 31,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 278008 game time, 302008 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: true), thunder time: 0 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at dhc.a(SourceFile:420)
	at cva.b(SourceFile:1912)
	at cva.b(SourceFile:418)
	at net.minecraft.client.main.Main.main(SourceFile:154)

-- System Details --
Details:
	Minecraft Version: 1.14 Pre-Release 1
	Operating System: Mac OS X (x86_64) version 10.12.6
	Java Version: 1.8.0_74, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 406978408 bytes (388 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB)
	JVM Flags: 8 total; -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
	Launched Version: 1.14 Pre-Release 1
	LWJGL: 3.2.1 build 12
	OpenGL: NVIDIA GeForce GT 640M OpenGL Engine GL version 2.1 NVIDIA-10.17.5 355.10.05.45f01, NVIDIA Corporation
	GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because ARB_framebuffer_object is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

	Using VBOs: Yes
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: vanilla
	Current Language: English (US)
	CPU: 4x Intel(R) Core(TM) i5-3330S CPU @ 2.70GHz