System Limits

This topic specifies maximum sizes and numbers of various SingleStore Helios components. Use the following links to navigate to a section below:

Workspace-Level Limits



Maximum workspaces in a group


Maximum number of workspaces to which a database can be attached in R/W mode


Maximum workspace size

S-80 (vcpu 640, memory 5120 GB)

Refer to the pricing page for more details.

Number of databases per workspace

No fixed limit. It depends on the size of each database. Databases are sized differently based on the number of partitions, amount of data, metadata and number of tables, etc.

Refer to SingleStore Helios Sizing Guidelines for more details.

Maximum number of concurrent queries

This varies according to the deployment size.

Maximum simultaneous client connections

This varies according to the deployment size.

Database-Level Limits


Max Spec (enforced)

Max Spec (recommended)


Number of tables in a database

Each table costs some per-table memory overhead.

Number of partitions in a workspace


Number of database partitions per node


Table-Level Limits


Max Spec (enforced)

Max Spec (recommended)


Number of columns per table


Row size in bytes

64KB *

Limit does not apply to variable-length strings such as VARCHAR, VARBINARY, TEXT, etc.

Length of names in characters (applies to table names, column names)


Number of indexes per table


Number of columns per index


Number of tables in a join for each SELECT


Number of entries in a SELECT projection (target) list


* The number of fields that will fit in the 64KB maximum row size is determined by the field types and how rows are laid out in the in-memory rowstore format. In some cases, writes (inserts and updates) to columnstore tables are implemented by storing the newly written rows in a rowstore format before flushing them to the column-oriented format. The row size limit applies to fixed-width data which includes a 4-byte nullability flag for nullable fields. The row size limit does not include the body of variable-width fields, but only the in-row portion, which includes an 8-byte memory location pointer and an optional 4-byte nullability flag. The sum of the in-row data size for all columns cannot exceed 64KB."

Naming Constraints




  • Maximum length is 64 characters unless specified otherwise below.

  • Name cannot be blank.

  • Name cannot end with a space.

Database names

Database names can only contain alphanumeric characters and underscores, and cannot start with a digit.

Table names

Table names can contain both alphanumeric and non-alphanumeric characters, but cannot contain the / character.

Other database objects (stored procedures, views, user-defined functions, user-defined aggregate functions, and table-valued functions)

Maximum length of 256 characters.

User names

Maximum length of 32 characters.

Role names

No length limit. Cannot contain commas or spaces.

Group names

No length limit. Cannot contain commas or spaces.

Last modified: December 9, 2022

Was this article helpful?