How do I verify the total rows inserted to a table?

I have table in cassandra with 9 columns
primary key ((column1, column2),forecastdate

I have inserted 10,000 records in this table by reading from cassandra v1.0.12 and writing to cassandra v3.x using a java program having insert queries

To validate data in target cassandra 3 host, I want check num of records inserted in ver 3.x

If I run select count(*) from table_name;
it returns me huge number of 2,109,761

While nodetool cfstats shows : Number of Keys (estimated) as 6,450

Want to understand how can I validate data after inserting into new cass version

The values provided by cfstats are not accurate before performing a compaction or a flush.

> The nodetool cfstats command provides statistics about one or more tables. It's updated when SSTables change through compaction or flushing.

source

To count the number of rows in a table I recommend the free tool DSBulk. Indeed a count(*) will timeout pretty quickly with a bit of volume.

dsbulk count --stats.modes global -k myKeyspace -t myTable

DSBulk reference documentation

The built-in CQL function COUNT() will return the number of partitions in the table, not just what you last inserted (provided it doesn't timeout).

Unless you have a way of filtering just the data you inserted, any method you use to count will return all the records in the table.

As a side note, the number of keys reported by nodetool cfstats is just an estimate. If you're interested, I've explained why it is not an accurate count in Why COUNT() is bad in Cassandra.

In any case, a more reliable way to count records in Cassandra is with the DataStax Bulk Loader (DSBulk) tool. It is open-source so it's free to use. It was originally designed for bulk-loading data to and exporting data from a Cassandra cluster as a scalable solution for the cqlsh COPY command.

DSBulk has a count command that provides the same functionality as the CQL COUNT() function but has optimisations that break up the table scan into small range queries so doesn't suffer from the same problems as brute-force counting.

DSBulk is quite simple to use and only takes a few minutes to setup. First, you need to download the binaries from DataStax Downloads then unpack the tarball. For details, see the DSBulk Installation Instructions.

Once you've got it installed, you can count the partitions in a table with one command:

$ cd path/to/dsbulk_installation
$ bin/dsbulk count -h <node_ip> -k ks_name -t table_name

Here are some references with examples to help you get started quickly:

• Docs - Counting data in tables
• Blog - Counting records with DSBulk
• Blog - DSBulk Intro + Loading data