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Glossary

This glossary defines common terms used in VeloDB Cloud documentation. Terms are grouped alphabetically. For implementation details, follow the links to the related documentation.

A​

Aggregate Key Model​

The Aggregate Key Model pre-aggregates rows that have the same key columns. It is designed for summary and reporting workloads where queries do not require the original detail rows. See Aggregate Key Model.

Availability Zone​

An availability zone is an isolated location within a cloud region where a warehouse or cluster can run. Choosing a zone close to your application can reduce network latency. See Create a SaaS Warehouse.

B​

Backend (BE)​

The backend, abbreviated as BE, is an Apache Doris service that stores data and executes query plan fragments. In a distributed query, the frontend sends work to one or more BEs. See Query Profile Analysis.

Bucket​

A bucket distributes the data in a partition into multiple tablets. The bucketing process helps spread data across nodes and enables parallel reads and writes. See Partitioning and Bucketing.

BYOC​

BYOC means bring your own cloud. In a BYOC warehouse, VeloDB Cloud installs and operates the warehouse in cloud resources in your own cloud account. See Create a BYOC Warehouse.

C​

Catalog​

A catalog is a metadata and connection definition that lets VeloDB Cloud access tables in an external data source. These catalogs are commonly used to query lakehouse systems and object storage without first copying the data into internal tables. See Catalogs and Lakehouse Catalog Overview.

CDC​

CDC means change data capture. It records inserts, updates, and deletes in a source system so that changes can be synchronized incrementally to VeloDB Cloud. See PostgreSQL CDC.

Cluster​

A cluster is a group of compute resources inside a warehouse. A warehouse can contain multiple clusters, and the clusters share the warehouse's stored data. See Create a Cluster.

Compaction​

In Apache Doris, compaction is a background process that merges data versions or files to reduce redundancy and improve storage and query efficiency. See Aggregate Key Model.

Compute-Storage Separation​

With compute-storage separation, compute resources and storage resources can scale and be managed independently. In VeloDB Cloud, stored data is shared by the clusters in a warehouse, while cluster compute and cache can be adjusted for workload needs. See Create a Cluster.

D​

Duplicate Key Model​

The Duplicate Key Model retains every inserted row without deduplication or pre-aggregation. It is the default table model and is suitable for append-only data such as logs, user behavior, and transaction details. See Duplicate Key Model.

E​

External Table​

An external table is a table definition that references data outside the warehouse, such as data in an object store or a lakehouse table format. External tables are accessed through a catalog and do not require the data to be loaded into internal tables first. See Lakehouse Overview.

F​

Frontend (FE)​

The frontend, abbreviated as FE, is an Apache Doris service that receives SQL requests, maintains metadata, creates execution plans, and coordinates query execution. The FE sends execution fragments to backend services. See Query Profile Analysis.

H​

HNSW​

HNSW means hierarchical navigable small world. It is a graph-based approximate nearest neighbor index used for high-performance vector retrieval. See HNSW.

I​

Inverted Index​

An inverted index maps terms or values to the rows that contain them. It accelerates text search and filtering without scanning every row. See Index Overview.

L​

Lakehouse​

A lakehouse combines the open storage and table formats of a data lake with the query and analysis capabilities of a data warehouse. VeloDB Cloud can use catalogs to query data in systems such as Hive, Iceberg, Hudi, and Paimon. See Lakehouse Overview.

M​

Materialized View​

A materialized view stores the result of a query so that repeated queries can read precomputed data. VeloDB Cloud can use materialized views to accelerate queries and reduce repeated computation. See Materialized Views.

MCP Server​

An MCP Server exposes VeloDB Cloud data and query capabilities to AI agents through the Model Context Protocol. The VeloDB Cloud MCP Server supports metadata discovery, SQL queries, and semantic-layer queries. See MCP Server User Guide.

MPP​

MPP means massively parallel processing. In an MPP architecture, a query is divided into tasks that run in parallel across multiple compute nodes. See Pipeline Execution Engine.

O​

Organization​

An organization is the VeloDB Cloud administrative scope that contains members, organization roles, billing settings, warehouses, and clusters. These organization roles control console access and are separate from warehouse SQL roles. See Members.

P​

Partition​

A partition divides a table into smaller, mutually exclusive subsets based on column values such as time or region. Partition pruning can reduce the data scanned by a query and simplify data lifecycle management. See Partitioning and Bucketing.

PrivateLink is a private network path for connecting a client or application in your cloud environment to a SaaS warehouse without exposing the connection through the public internet. See Choose a Connection Path.

A public link is a public network connection endpoint for a SaaS warehouse. It lets authorized clients connect through the internet using the warehouse connection information. See SaaS Public Link.

Q​

Query Profile​

A query profile records query execution details, including operator metrics, elapsed time, row counts, and memory usage. It helps identify slow operators and other query performance bottlenecks. See Query Profile Analysis.

R​

RAG​

RAG means retrieval-augmented generation. A RAG application retrieves relevant information from a knowledge base and provides it as context to a generative AI model. VeloDB Cloud supports RAG workflows with vector search, text search, and SQL analytics. See RAG.

Routine Load​

With routine load, a continuously running import job consumes streaming data, such as records from Kafka, and loads it into a VeloDB Cloud table. See Routine Load.

S​

SaaS​

SaaS means software as a service. In a SaaS warehouse, VeloDB Cloud provides and manages the underlying cloud resources and services, so you can use the warehouse without managing its infrastructure. See Create a SaaS Warehouse.

Semantic Model​

A semantic model describes the business meaning of tables, entities, dimensions, and measures in a structured format. The VeloDB Cloud MCP Server uses a committed semantic model to answer metric queries with consistent business definitions. See Semantic Model.

Stream Load​

The stream load method is an HTTP-based data import method for loading local files or request bodies directly into a VeloDB Cloud table. It is suitable for small batches and real-time or near-real-time ingestion. See Stream Load.

T​

Tablet​

A tablet is a physical data shard created by bucketing a table partition. These tablets are distributed across backend nodes so that data can be stored and processed in parallel. See Partitioning and Bucketing.

U​

Unique Key Model​

The Unique Key Model keeps one latest row for each set of key columns. Inserting a row with an existing key updates that row, making this model suitable for upserts and frequently changing dimension data. See Unique Key Model.

V​

Vector Index​

A vector index accelerates similarity search over vector data. VeloDB Cloud supports approximate nearest neighbor indexes such as HNSW and IVF for vector retrieval. See Vector Index Overview.

W​

Warehouse​

A warehouse is the primary resource and SQL scope in VeloDB Cloud. It contains clusters, stored data, connection settings, and warehouse-level users and roles. See Warehouse Settings.

Warehouse Users and Roles​

Warehouse Users and Roles are the warehouse-level accounts and SQL permissions used by applications, BI tools, and SQL clients. They are separate from organization members and organization roles used to access the VeloDB Cloud console. See Warehouse Users and Roles.