2DC: two data center, a common DR or HA configuration in the days before distributed systems
2FA: two-factor authentication
ACID: the 4 guarantees of a transactional database are Atomicity, Consistency, Isolation, Durability
aggregation: an operation that a client app can perform in SQL to simplify a lot of data into a simple result (e.g. counting)
AOST: As of System Time
Aphyr: the usual name Kyle Kingsbury goes by
ARR: Annual Recurring Revenue (also see CARR)
AWS (Amazon Web Services): Amazon's Cloud hosting
Azure: Microsoft's Cloud hosting
Bikeshed: many engineers spending a lot of time debating a minor issue - see the story here
BSL: Business Source License, a license applied to part of our codebase. Code licensed under the BSL becomes automatically re-licensed under the Apache License (open source) after 3 years. See also CCL.
CalVer: calendar versioning scheme for CockroachDB. See here for details.
CAP Theorem: a theorem that says a distributed database can only deliver two out of three of Consistency, Availability, Partition-ability
Cassandra: another DB product we hear about often
CBO: Cost-based Optimizer
CCL: Cockroach Community License, a license applied to part of our codebase that corresponds to “Enterprise” features. See also BSL.
CDC: acronym for “Change Data Capture”. CockroachDB’s version of change feeds, see definition below.
CEA: Cockroach Enterprise Architect
Change feeds: a way for a user to ask the database to ping the user (or an app, i.e. a 3rd party) back when some data changes. The changed data is notified to the 3rd party (usually) asynchronously, i.e. possibly not atomically with the transaction where the change occurs. See also "Trigger".
Chaos: testing method that stops nodes in a test cluster unpredictably
Chaos monkey: program that performs chaos testing
CI (Continuous integration): program that runs tests and produces reports automatically in the background
Cloud: someone else's computer
Cluster: An ambiguous term, especially in the context of CockroachCloud. Generally, one of:
[CRDB/Cockroach/CockroachDB] Cluster: one deployment of CockroachDB, a group of one or more nodes (servers)
[Kubernetes] Cluster: A group of one or more Kubernetes nodes, usually including a leader node.
[CC/CockroachCloud] Cluster: One or more Kubernetes Clusters running a single deployment of CockroachDB
[Host/Serverless] Cluster: One deployment of CockroachDB, usually on Kubernetes, that contains many Tenants.
CockroachCloud: a hosting service provided by CRL, where CRL runs CockroachDB clusters on behalf of customers.
Code review: A process by which a second (or more) engineer reviews code before it is merged into the main codebase. At CRL, every code must be reviewed, and approved (see LGTM).
Code yellow: moving an issue to top company priority (idea comes from Google). During a code yellow, any task pertaining to the code yellow takes precedence over non code yellow related tasks.
CRL: acronym for Cockroach Labs
CRUD: Create, Read, Update, Delete … basic operations on a database object
CSM: Customer Success Management
Cutting the release: selecting one particular version of the product to publish out
Data sovereignty: the demand for some apps/companies to have data located in specific places geographically, for example in EU data for citizens must be hosted in the EU
DDL (Data Definition Language): the part of SQL that apps can use to manage tables and indexes (the schema), e.g. create/rename/delete them. This includes e.g. "CREATE TABLE" but does not include "SELECT". See also "DML."
Delta: an incremental change, such as between git commits or incremental backups.
Denormalization: An explicit copy of some normalized data in a different format, in order to enable faster access. "Denormalized data" = indexes, materialized views, etc. --- all the stuff that copies "base" data into a different format for speed on operations that aren't by primary key.
DML (Data Manipulation Language): the part of SQL that apps can use to read and write data, e.g. query tables or update table rows. This includes e.g. "SELECT" or "INSERT" but does not include "CREATE TABLE". See also "DDL."
ELA: Enterprise License Agreement
Encryption at rest: have the data encrypted in the database, not only when queried by clients
ETL: Extract / Transform / Load … a type of data integration
FHMP: Forever hold my peace, a neutral way to bow out of a debate / code review
FMEA: Failure Mode & Effects Analysis
GC: garbage collection, the process of actually deleting and cleaning up items that have been marked for deletion
GCE: Google Compute Engine, the compute service (VMs) offered by GCP
GCP: Google Cloud Platform, Google's Cloud services
GDPR: General Data Protection Regulation, EU data security laws
Geospatial index: An index that is efficient for storing 2d coordinates (such as lat/long) such that two points on the coordinate system that are close on the (lat/long) map are stored relatively close together in the index ordering. The uniqueness of the Geospatial index is in maintaining the "closeness" when going down from 2 dimensions (lat/long) to one dimension (the index). Usually achieved with a space filling curve
GIS (Geographical Information System): A system optimized for geographical data, makes heavy use of geospatial indexes, but also spatial-temporal indexes (combination of geospatial data and time series data), and also can understand and digest data stored in standard formats used for geographic data.
Git: a tool and database to store and share source code
HLC: Hybrid Logical Clock
HTAP: Hybrid Transactional/Analytical Processing. I.e. OLAP + OLTP.
ILM: Information Lifecycle Management, “a wide-ranging set of strategies for administering storage systems on computing devices”
Index: A copy of some parts of a database table, ordered to make lookups very quick according to the index columns. There is always a "primary index", ordered by primary key, making lookups of a row if you know the primary key very fast. Other indexes are called "secondary indexes", and are ordered by some other criteria (could be some other columns, or even combinations of columns, or even combinations of columns from different tables). An index is a denormalization.
Jepsen: a tool that tests databases in a harsh way, made by Aphyr; also the name of Aphyr's blog about database testing
K8s: shorthand for Kubernetes
KMS: (AWS) Key Management Service
LB: Load Balancer (see also NLB)
LGTM: Short for "looks good to me", the typical way one says they approve of a PR at the end of a code review, okaying it for merge. LGTM doesn't necessarily mean you can hit the merge button, for instance "LGTM, if you fix XYZ" still means XYZ should be done. They are just trusting you to do so, and don't necessarily need to verify that (if XYZ is trivial).
LOQ: Loss of Quorum. In the RAFT consensus protocol, “quorum” is the number of voters necessary to make a decision. Loss of Quorum is when there aren’t enough voters available, and no consensus can be reached.
LSM: Log Structured Merge Tree, a data structure used by Pebble/CRDB (as well as RocksDB and others) for organizing storage on disk. Alternative to the B+ trees traditionally used in databases. A large topic, read more here or on Wikipedia.
Materialized view: a SQL view where the data of the view is duplicated from the original table (As opposed to a simple/dematerialized view, where a query on the view is automatically translated to a query on the underlying table). Materialized views are useful when the query that creates the view is complex and the views is used more often than the data is changed, because it then saves SQL execution time for the clients using the view.
Merge: the action of accepting a PR to the main product
Merge skew: An error condition encountered by the entire team when two changes on the git repository get merged concurrently and the result of both changes together causes CockroachDB to break. We use the ‘bors’ merge automation bot to prevent concurrent merges and thus merge skews. Merge skews can also be avoided by a healthy regimen of regularly rebasing, i.e. re-creating the patches on top of the latest git revision.
Mongo: short for MongoDB, another DB product we hear about often
MPP: Massively Parallel Processing
MRC: Monthly Recurring Charge
Multi-tenant CockroachDB: an extension of the base CockroachDB architecture where multiple customers (“tenants”) can use the same CockroachDB cluster safely. A Multi-tenant cluster has two kinds of “nodes”: KV nodes that store the data for all tenants, and SQL nodes that are specific to each tenant.
NLB: Network Load Balancer
Node: (CockroachDB node) one instance of a CockroachDB server process, that stores part of the data in an entire CockroachDB cluster. A single cluster can have many nodes. In a serverless (multi-tenant) cluster, we don’t use the word “node” alone and instead specify “KV node” or “SQL pod”.
Normalization: Normalization refers to the process of reducing copies of data as much as possible so that there aren't too many logical copies of the same information (as that would increase the possibility of errors if some copies are updated without updating all copies). See wikipedia. Usually contrasted with explicit denormalization.
NRC: Non-Recurring Charge
OIDC: Open ID Connect, an authentication protocol
OKRAs - Objectives, Key Results & Actions
OLAP (Online Analytics Processing): a class of applications where the most common queries are long and touch most of the data at a time with complex computations -- contrast with OLTP
OLTP (Online Transaction Processing): a class of applications where the most common queries are short and touch a bit of data at a time with simple computations -- contrast with OLAP
OOM: Out Of Memory … an undesirable condition for a CockroachDB node
ORM (Object-Relational Mapping): a piece of software used by an app to access a DB
Pebble: CockroachDB’s storage engine, an embedded key-value store based on RocksDB. See our blog post.
P2S: Problems to Solve
PR (Pull Request): a proposal for a change to the source code submitted for review to colleagues. See "merge"
RACI matrix: the list of who’s Responsible, Accountable, Consulted, and Informed
Range: a logical portion of the data in a DB. In other distributed databases called a "shard", "chunk", or "tablet". Each range can have multiple physical copies, on different nodes. Each copy is called a “replica”.
RBAC: Role-based access control
RCA: Root Cause Analysis
RDS: (Amazon’s) Relational Database Service
Rebase: Take a git commit (the set of line-by-line changes) and apply those deltas to a different commit. Usually done because "master" moved on while you were working on a change, and now your commit won't merge cleanly. Usually a good habit to do before merging anyway, as not all conflicts are caught by git. See "merge skew".
Reg cluster: short for "registration cluster", a CockroachDB cluster ran by CRL internally to store telemetry data sent by customers.
Reg server: an internet microservice ran by CRL that receives telemetry data sent by customers.
Replication factor: how many copies there are of each Range in a DB or Zone. Default is 3.
Replica: one of the copies of some Range in a DB or Zone. There are
replication factorreplicas of a range across a cluster.
RFC: Short for "Request for comments". An RFC is a description of a larger change, written to outline why the change, what the change will consist of, etc. before the code is written. Used to build consensus around a code, before diving into writing code for weeks. This lets issues/thoughts get surfaced early, so that time is not wasted writing code, only to discover in a code review that there was a much better way to do things, if only, say, the author had requested some comments on their thoughts before diving off.
RPO / RTO: Recovery Point Objective / Recovery Time Objective … what data/service/capability is to be restored and how long it takes to restore it, two key measures in a Disaster Recovery plan
SemVer: semantic versioning scheme, which we used previously for CockroachDB. Now using calver instead.
Server: something running in the backend of a client-server architecture. We don’t like the word “server” too much at CRL because it is very ambiguous. It can designate too many things! We have CockroachDB “servers” (KV nodes and SQL pods), CockroachCloud “servers” (monitoring, console, orchestration), testing “servers” etc.
SH: often refers to self-hosted customers
SIAM: Service Integration and Management
SIG: Severe Incidents Group
SLA: Service Level Agreement
SLI: Service Level Indicator
SLO: Service Level Objective
Spanner (Google product): another project we get inspiration from
SRE: Site Reliability Engineer - a discipline that incorporates aspects of software engineering and applies them to infrastructure and operations problems, with the goal of creating scalable and reliable software systems
SST: State Snapshot Table
TCO: Total Cost of Ownership, a measure of particular interest to purchasers. TCO typically includes one-time fees and recurring fees for licensing, maintenance, support, etc.
Team City: one of our continuous integration tools
Time series: a way to organize data in a DB where the data is organized primarily by time; commonly used to store events over time; sometimes subject to OLAP applications
TLS: Transport Layer Security (successor to Secure Sockets Layer)
TPC-C: a database benchmark developed in 1992 to simulate a traditional OLTP application (i.e. wholesale distributor w/ warehouses and retail locations). See also TPC-E.
TPC-E: a database benchmark developed in 2007 to simulate a more modern OLTP application (i.e. a stock brokerage w/ fluctuating stock prices and many concurrent orders). See also TPC-C.
Trigger: a way for a user to ask the database to ping the user (or an app) back when some data changes, or run a stored procedure on the server. The trigger (usually) happens before the transaction commits, so that the consumer can see the changes atomically. See also "Change feed".
TRN: Technical Roadmap Narrative
TSE: Technical Support Engineer
TTL: Time To Live, generally the configurable longevity for an object. Most frequently encountered in CRDB as a GC TTL, the time for old MVCC values to live before being garbage collected
UAT: User Acceptance Testing
WAL: Write-Ahead Logging
XA Transactions: 2 phase commit protocol referred to as XA (eXtended Architecture)
YCSB: Yahoo Cloud Serving Benchmark, designed to measure NoSQL and other cloud service databases.
Zone config/zones: CockroachDB way to set different configuration parameters to different parts of a cluster, can be used to set constraints on replication (e.g. at least one copy must be on a different continent) or for data sovereignty (e.g. no copies of this data should reside outside EU territory)