Erigon writes tons of data to Caplin/temp with Caplin disabled

[academe-01]

is it a bug or expected behaivor ?

Erigon (with prysm) with disabled caplin writing to caplin/temp tons of data. I do have already 466 GB on initial Sepolia sync!

INFO[01-12|22:45:41.707] Build info                               git_branch=release/2.61 git_tag=v2.61.0-7-g8ed124b git_commit=8ed124b1df235b72eb6795b516b3bac2cdb2afee

erigon --lightclient.discovery.port=4008 --lightclient.discovery.tcpport=4009 --sentinel.port=7779 --authrpc.jwtsecret /Volumes/Sepolia/jwt.hex --torrent.download.rate=200mb --snapshots=false --chain=sepolia --datadir=/Volumes/Sepolia/erigon --port=30309 --http.port=8548 --authrpc.port=8554 --private.api.addr=127.0.0.1:9093 --http --ws --http.api=eth,debug,net,trace,web3,erigon,ots,ots2 --etl.bufferSize=4096MB --batchSize=4096MB --torrent.port=42071 --db.pagesize=16384

From diagnostics:

Very interesting picture in Allocs profile (attached as .svg)

erigon_log.zip

[academe-01]

Update,
after some hours temp mdbx in Caplin dir reached 627 GB and Erigon started
Beginning downloaded blocks insertion stage
so basically the whole content of this tmp/mdbx just got copied into chaindata/mdbx

Therefor maximum space was required 627GB x 2 = 1254 GB and this is only on Sepolia....
I can only imagine mainnet.

After [EngineBlockDownloader] Finished downloading blocks from=0 to=7478214 erigon kept Caplin/mdbx-tmp file
and started to complain Could create temporary mdbx err="stat /Volumes/Sepolia/erigon/temp: no such file or directory"

on restart folder /Volumes/Sepolia/erigon/temp was created
surprising why it was not created at first start (with empty datadir, very first run)