Glossary

Resident set size

RSS

Resident Set Size

A measure of process memory pages resident in RAM. It is not maximum heap or the total system cost; compare measurements under aligned conditions.

Resource health

An assessment of resources, such as Deployment readiness in Argo CD. It differs from configuration synchronization and a business operation test. Healthy does not replace checking application behavior.

Resource management

Defining ownership, limits and release of resources such as connections, files or workers. Handle failure, timeout and cancellation as well as success.

RESPX

A product name or identifier; no acronym expansion is invented.

A test tool controlling HTTPX client responses. Mock tests do not prove compatibility with the real external provider.

REST

REST

Representational State Transfer

An architectural style for distributed systems involving resources, a uniform interface and stateless requests. JSON and CRUD endpoints alone do not establish full REST conformance.

Retrieval-augmented generation

RAG

Retrieval-Augmented Generation

Adding retrieved material to model context before answering. Retrieval relevance, source permissions and answer evaluation are separate concerns.

Retry

Another attempt after failure or an unknown outcome. Define repeat safety, attempt limits, time budget and delays; retries can amplify overload.

Retry budget

A limit on retry count or aggregate cost within a scope. It prevents failure-driven work amplification; error classification and idempotency are still needed.

Rivest–Shamir–Adleman

RSA

Rivest–Shamir–Adleman

Public/private-key cryptographic operations. Security also depends on the scheme, parameters and key management.

Role-based access control

RBAC

Role-Based Access Control

Granting permissions through roles such as CUSTOMER and ADMIN. A role often remains insufficient: verify the particular resource’s owner or tenant.

Rounding mode

HALF_UP and UNNECESSARY are rounding-mode names, not abbreviations.

A rule deciding the result when a number does not fit the chosen scale or precision. In BigDecimal, HALF_UP rounds to the nearest value and breaks ties away from zero; UNNECESSARY requires an exact result and fails if rounding is needed. Specify when rounding occurs too.

Route table

Rules selecting a packet’s next destination from its destination address. A gateway route is not an access permission; network policies and security rules still apply.

Row-level security

RLS

Row-Level Security

Database policies restricting access to rows. Verify roles, session context and bypass paths; adding a policy does not replace application-isolation tests.

RPO

RPO

Recovery Point Objective

Acceptable data loss expressed as the interval between failure and the recovered point. It needs a matching backup or replication strategy verified in practice.

RS256

A product name or identifier; no acronym expansion is invented.

The JOSE identifier for RSASSA-PKCS1-v1_5 with SHA-256 signatures. Pin permitted algorithms and keys at verification; do not trust the token header alone.

RTO

RTO

Recovery Time Objective

A target time for restoring operation after failure. It includes environment preparation, validation and reopening the service, not merely loading a backup.

Ruff

A Python linter and formatter. It enforces style and catches selected static mistakes; it does not test business requirements.

Saga and compensation

A multi-step process coordinating local operations and compensating actions. Compensation is another business operation that can fail; it is not a global rollback.

Sandbox

An environment restricting executed code’s resource access. Verify file, network, process and secret boundaries; a separate work directory is not a sandbox by itself.

Scheduler

Selects a node for an unassigned Pod based on requirements and availability. It does not start containers; the selected node’s kubelet does.

Scoped dependency

A dependency created or renewed for a defined scope, such as a request. Its exact lifecycle depends on the framework; capturing it in a singleton can defeat intended isolation.

Sealed type

A type with a controlled set of permitted subtypes. It helps express result variants and check their handling; it does not replace validation.

Secret

A confidential value granting access or proving identity, such as an API token. Keep it out of code, images and logs; exposure requires revocation or rotation.

Security Group

SG

Security Group

Stateful traffic rules attached to AWS resources. Replies to allowed connections are tracked. Network access to RDS does not replace authentication or SQL privileges.

Security Token Service

STS

Security Token Service

An AWS service issuing temporary credentials, such as for role assumption. Short lifetimes reduce exposure but do not fix excessive role permissions.

Self-heal

Argo CD reconciliation of detected cluster changes through synchronization. It does not fix every application bug or automatically recover lost data.

Semantic search

Retrieves by meaning similarity, often using vector representations. It can help paraphrases but does not replace authorization, edition filtering or relevance evaluation.

Semaphore

A mechanism limiting concurrent resource users through permits. Release permits after failures and cancellation too.

Sentinel value

A distinguished value representing a state such as a missing field. When None is valid data, a separate marker object can distinguish it from an omitted field.

Serialization

Converting program data to a transport or storage representation; deserialization reverses the process. Explicitly define money, dates and missing-value representations.