Astra database limits

DataStax Astra sets limits for databases to ensure good practices, foster availability, and promote optimal configurations for your database.

DataStax Astra offers a $25.00 free credit per month, allowing you to create an Astra database for free. Create a database with just a few clicks and start developing within minutes.

Each plan includes a $25.00 free credit per month. The $25 credit is good for approximately 30 million reads, 5 million writes, and 40GB of storage per month.

The following limits are set for all databases created using DataStax Astra. These limits ensure good practices, foster availability, and promote optimal configurations for your database.

Columns

Parameter	Limit	Notes
Size of values in a single column	5 MB	Hard limit.
Number of columns per table	50	Hard limit.

Parameter

Limit

Notes

Size of values in a single column

5 MB

Hard limit.

Number of columns per table

Hard limit.

Tables

Parameter	Limit	Notes
Number of tables per database	200	A warning is issued when the database exceeds 100 tables.
Table properties	Fixed	All table properties are fixed except for Expiring data with time-to-live.
Secondary index	1	Limit is per table.
Materialized view	2	Limit is per table. A warning is issued if the materialized view will create large partitions.

Parameter

Limit

Notes

Number of tables per database

200

A warning is issued when the database exceeds 100 tables.

Table properties

Fixed

All table properties are fixed except for Expiring data with time-to-live.

Secondary index

Limit is per table.

Materialized view

Limit is per table. A warning is issued if the materialized view will create large partitions.

Cassandra Query Language (CQL)

At this time, user-defined functions (UDFs) and user-defined aggregate functions (UDAs) are not enabled.

Parameter Limit Notes

Parameter	Limit	Notes
Consistency level	Fixed	Supported consistency levels: Reads: Any supported consistency level is permitted Writes: LOCAL_QUORUM and LOCAL_SERIAL
Compaction strategy	Fixed	Only the SizeTieredCompaction strategy is supported.
Lists	Fixed	Cannot `UPDATE`, `INSERT`, or `DELETE` a list value by index because Astra does not allow list operations which perform a read-before-write.
Page size	Fixed	The proper page size is configured automatically.
Large partition	Warning	A warning is issued if reading or compacting a partition that exceeds 100 MB.

Consistency level

Fixed

Supported consistency levels: Reads: Any supported consistency level is permitted Writes: LOCAL_QUORUM and LOCAL_SERIAL

Compaction strategy

Fixed

Only the SizeTieredCompaction strategy is supported.

Lists

Fixed

Cannot UPDATE, INSERT, or DELETE a list value by index because Astra does not allow list operations which perform a read-before-write.

Page size

Fixed

The proper page size is configured automatically.

Large partition

Warning

A warning is issued if reading or compacting a partition that exceeds 100 MB.

cassandra.yaml

If you are an experienced Cassandra or DataStax Enterprise user, you are likely familiar with editing the cassandra.yaml file. For Astra, the cassandra.yaml file cannot be configured.

The following limits are included in Astra:

// for read requests
        page_size_failure_threshold_in_kb =  512
        in_select_cartesian_product_failure_threshold =  25
        partition_keys_in_select_failure_threshold = 20
        tombstone_warn_threshold = 1000
        tombstone_failure_threshold = 100000

// for write requests
        batch_size_warn_threshold_in_kb = 5
        batch_size_fail_threshold_in_kb = 50
        unlogged_batch_across_partitions_warn_threshold = 10
        user_timestamps_enabled = true
        column_value_size_failure_threshold_in_kb = 5 * 1024L
        read_before_write_list_operations_enabled = false

// for schema
        fields_per_udt_failure_threshold = 10
        collection_size_warn_threshold_in_kb =  5 * 1024L
        items_per_collection_warn_threshold =  20
        columns_per_table_failure_threshold = 50
        secondary_index_per_table_failure_threshold = 1
        materialized_view_per_table_failure_threshold = 2
        tables_warn_threshold = 100
        tables_failure_threshold = 200

// for node status
        disk_usage_percentage_warn_threshold =  70
        disk_usage_percentage_failure_threshold =  80
        partition_size_warn_threshold_in_mb =  100

// SAI Table Failure threshold
        sai_indexes_per_table_failure_threshold = 10

Workloads

Astra workloads are limited to 4096 ops/s/coordinator by default. If you see a "Rate limit reached" error in your application and want your limit raised, please open a support ticket.