Cannot delete blocks

[heliosVII-tech]

For a particular reason I want to delete blocks. But when I call rawdb.DeleteBlock it doesn't actually delete the old block. For example, the code below prints the same value for blockBefore and blockAfter (sans pointer differences). How do I actually delete blocks to save disk space?

func (bc *BlockChain) GetBlockByNumber(number uint64) *types.Block {
	hash := rawdb.ReadCanonicalHash(bc.db, number)
	if hash == (common.Hash{}) {
		return nil
	}

	if number == 1000 {
		blockBefore := bc.GetBlock(hash, number)

                 // clear from cache
		present := bc.blockCache.Remove(hash)
                 bc.blockCache.Purge()

                // try this way
		rawdb.DeleteBlock(bc.db, hash, number)

                // try using batches
		batch := bc.db.NewBatch()
		i := 0
		for _, hash := range rawdb.ReadAllHashes(bc.db, number) {
			i++
			rawdb.DeleteBlock(batch, hash, number)
		}
		if err := batch.Write(); err != nil {
			log.Error("Batch write got error", "err", err.Error())
		}

		blockAfter := bc.GetBlock(hash, number)
		log.Info("GetHeader", "number", number, "blockBefore", blockBefore, "blockAfter", blockAfter, "present", present, "i", i)
	}

	return bc.GetBlock(hash, number)
}

Is there something obvious missing here? I see that sidechains are deleted in a similar manner.

[s1na]

I'm guessing the block is somewhat old and hence stored in the freezer (not in leveldb). And right now freezer doesn't support deletion. But that feature is not far off: #23954

[karalabe]

We don't support deleting blocks.

[maurodelazeri]

@karalabe I exported a range of blocks in an archive node with geth export and im trying to import this range in a read-only full node that I want to have this range of blocks with archive data... is this possible? while I import I get this message

INFO [12-05|02:35:21.235] Skipping batch as all blocks present batch=60 first=99299a..1a532a last=25ac15..f65ff1