We are using BODS 12.2.3.3 and we have more than 8 jobs running for every 5 minutes as a result the metadata tables are growing rapidly
the Al_statistics metadata has more than 9000000 records.
Yes, you can delete the data in that table. However, it may be that your jobs make use of that data.
I have truncated that table in some environments without any problems. At the very least, make sure that no jobs are running when you truncate that table.