krakenuniq-build error and krakenuniq results are unclassified

[QuietgraceH]

Hi, thanks for creating such a useful tool!
When I use krakenuniq(version 1.0.4), I download the database first by code:

krakenuniq-download -db /data/bacteria2 --threads 10 refseq/bacteria
krakenuniq-build --db /data/krakenuniq_db/bacteria2--kmer-len 31 --threads 20 --taxids-for-genomes --taxids-for-sequences --jellyfish-bin /data/biosoft/soft2024/jellyfish/jellyfish_1.1.12/bin/jellyfish  --work-on-disk --jellyfish-hash-size 6500000000000

When run krakenuniq-build I get this error message:

Kraken build set to minimize RAM usage.
Found 37484 sequence files (*.{fna,fa,ffn,fasta,fsa}) in the library directory.
Skipping step 1, k-mer set already exists.
Skipping step 2, no database reduction requested.
Sorting k-mer set (step 3 of 6)...
db_sort: Getting database into memory ...Loaded database with 38712964423 keys with k of 31 [val_len 4, key_len 8].
Loaded database with 38712964423 keys with k of 31 [val_len 4, key_len 8].
db_sort: Sorting ...terminate called after throwing an instance of 'std::bad_alloc'
what(): std::bad_alloc
/data/anaconda3/envs/krakenuniq/share/krakenuniq-1.0.4-1/libexec/build_db.sh: Line 46: 832010 Abandoned db_sort -z -t 20 -n 15 -d database.jdb
-o database0.kdb.tmp -i database.idx

So I gave up building it myself and used the built database. But the running result was unclassified.(https://benlangmead.github.io/aws-indexes/k2)

krakenuniq -db /data/krakenuniq_db/bacteria2 --report-file test_report  /data/pbmc_meta/C_0.fq.gz --output test_output

When run krakenuniq I get this error message:

/data/anaconda3/envs/krakenuniq/share/krakenuniq-1.0.4-1/libexec/classify -d /data/krakenuniq_db/bacteria2/database.kdb -i /data/krakenuniq_db/bacteria2/database.idx -o test_output -r test_report -a /data/krakenuniq_db/bacteria2/taxDB -p 12
Database /data/krakenuniq_db/bacteria2/database.kdb
Loaded database with 34335766180 keys with k of 31 [val_len 4, key_len 8].
Reading taxonomy index from /data/krakenuniq_db/bacteria2/taxDB. Done.
Writing Kraken output to test_output
^M Processed 7878 sequences (0.00% classified)^M Processed 15787 sequences (0.00% classified)^M Processed 23742 sequences (0.00% classified)^M Processed 31647 sequences (0.00% classified)^M Processed 39494 sequences (0.00% classified)^M Processed 47357 sequences (0.00% classified)^M Processed 55221 sequences (0.00% classified)^M Processed 63130 sequences (0.00% classified)^M Processed 71019 sequences (0.00% classified)^M Processed 78871 sequences (0.00% classified)^M Processed 86737 sequences (0.00% classified)^M Processed 94560 sequences (0.00% classified)

• can you help point out the reason why the build failed?

• Secondly, I hope you can point out why when downloading the built database and running it, all the results are unclassified.

Thank you very much.