如何使用 Datastax 批量加载程序（Ubuntu）将数据加载到 Apache Cassandra？

Question

When I want to upload data to my "Test Cluster" into Apache Cassandra I open the terminal and then:

export PATH=/home/mypc/dsbulk-1.7.0/bin:$PATH

source ~/.bashrc

dsbulk load -url /home/mypc/Desktop/test/file.csv -k keyspace_test -t table_test

But...

At least 1 record does not match the provided schema.mapping or schema.query. Please check that the connector configuration and the schema configuration are correct.
Operation LOAD_20201105-103000-577734 aborted: Too many errors, the maximum allowed is 100.

total | failed | rows/s | p50ms | p99ms | p999ms | batches
  104 |    104 |      0 |  0,00 |  0,00 |   0,00 |    0,00

Rejected records can be found in the following file(s): mapping.bad
Errors are detailed in the following file(s): mapping-errors.log
Last processed positions can be found in positions.txt

What does it means? Why I can't load?

Thank you!

Answer 1

The error is that you're not providing the mapping between CSV data & table. It could be done 2 ways:

1. If CSV file has header with column names matching to the column names in Cassandra, then use -header true
2. Provide mapping explicitly using the -m option (see docs ) - you need to map CSV columns into Cassandra columns.

There is a very good series of the blog posts about different aspects of DSBulk usage:

• https://www.datastax.com/blog/2019/03/datastax-bulk-loader-introduction-and-loading
• https://www.datastax.com/blog/2019/04/datastax-bulk-loader-more-loading
• https://www.datastax.com/blog/2019/04/datastax-bulk-loader-common-settings
• https://www.datastax.com/blog/2019/06/datastax-bulk-loader-unloading
• https://www.datastax.com/blog/2019/07/datastax-bulk-loader-counting
• https://www.datastax.com/blog/2019/12/datastax-bulk-loader-examples-loading-other-locations

the first two of them covers data loading in great details

Answer 2

It means that the columns in the CSV input file does not match the columns in your table_test table. You can get the details of the schema mismatch in the mapping-errors.log so you know which column(s) are problematic.

Since the CSV columns don't match the table schema, you will need to manually map them by specifying the --schema.mapping flag.

For details, see the DSBulk Common options page. You can also have a look at schema mapping examples inthis blog post . Cheers!