# Documentation changelog > **For AI agents:** the complete documentation index is at [llms.txt](https://questdb.com/docs/llms.txt). Every page is available as markdown by appending `.md` to its URL, or by sending an `Accept: text/markdown` request header. Recent updates and improvements to the QuestDB documentation. # Documentation changelog This page tracks significant updates to the QuestDB documentation. ## September 2026 ### QuestDB Enterprise Releases - [4.0.1](https://questdb.com/release-notes/) - Released September 1, 2026 ### New - [Memory limits](/docs/configuration/cairo-engine/#memory-limits) - New section covering the per-query, materialized view refresh, WAL apply, and live view refresh memory limits, what counts toward them, and what happens on a breach, plus the previously undocumented [`cairo.mat.view.max.refresh.retries`](/docs/configuration/materialized-views/#cairomatviewmaxrefreshretries), [`cairo.mat.view.refresh.busy.retry.limit`](/docs/configuration/materialized-views/#cairomatviewrefreshbusyretrylimit), [`cairo.mat.view.refresh.busy.retry.timeout`](/docs/configuration/materialized-views/#cairomatviewrefreshbusyretrytimeout), [`cairo.write.back.off.timeout.on.mem.pressure`](/docs/configuration/cairo-engine/#cairowritebackofftimeoutonmempressure), [`ram.usage.limit.bytes`](/docs/configuration/cairo-engine/#ramusagelimitbytes), and [`ram.usage.limit.percent`](/docs/configuration/cairo-engine/#ramusagelimitpercent) keys - [RBAC memory limits](/docs/security/rbac/#memory-limits) - Per-user, per-group, and per-service-account query memory limits in QuestDB Enterprise: `SET MEMORY LIMIT` on `ALTER USER`, `ALTER GROUP`, and `ALTER SERVICE ACCOUNT`, how limits resolve, the `SET MEMORY LIMIT` permission, and the upgrade migration - [ALTER GROUP](/docs/query/sql/acl/alter-group/) - New reference page covering `SET MEMORY LIMIT` and external alias mapping - [Migrate QuestDB onto the Kubernetes Operator](/docs/enterprise-kubernetes-operator/getting-started/migrate/) - Move an existing Enterprise deployment onto the Operator with a replica-first cutover: restore the source backup, consume replication WAL, then promote after a controlled source drain - [Copy a schema to another instance](/docs/cookbook/operations/copy-schema-between-instances/) - Recreate one instance's tables, views, and materialized views on another from `SHOW CREATE DATABASE`, either by replaying the statements over the REST API or by dumping them to a `.sql` file, with `INCLUDE (SCHEMA)` and `INCLUDE (ACL)` for separating structure from permissions on Enterprise, plus the Web Console schema explorer as a manual alternative and the ordering caveat that comes with it - [SUBSAMPLE](/docs/query/sql/subsample/) - New SQL keyword that reduces a query result to a subset of its existing rows, without interpolating values. Covers the six methods with a diagram each: `lttb` for line charts, with a gap-preserving mode, `minmax` and `m4` for per-time-bucket envelopes, `uniform` and `cadence` for position-based selection, and `sdt` (Swinging Door Trending) for error-bounded compression with a `2 * compdev` reconstruction bound and an animated walkthrough. Also covers where the clause goes in a query, output order, `NULL` handling, and which query shapes each method accepts - [SUBSAMPLE window functions](/docs/query/functions/window-functions/reference/#subsample-window-functions) - New category with `cadence()`, `lttb()`, `m4()`, `minmax()`, `sdt()`, and `uniform()`, which return a Boolean keep flag per row instead of the reduced row set. Covers the outer-query filter pattern, the ordering, framing, and `NULL` rules of each function, `PARTITION BY` and `IGNORE NULLS` support on `sdt()`, and [when to use each form](/docs/query/sql/subsample/#window-function-form) ### Reference - Added [`cairo.sql.subsample.max.rows`](/docs/configuration/cairo-engine/#cairosqlsubsamplemaxrows), the input row limit for the `lttb`, `m4`, `minmax`, `uniform`, and `cadence` methods of `SUBSAMPLE`. It does not apply to `sdt` ### Updated - [Node.js client](/docs/connect/clients/nodejs/) - Rewrote the page for QWP support in `@questdb/nodejs-client` 5.0.0: pooled ingestion and streaming SQL queries from one connect string, every column type, compiled object-row writers, acknowledgements, transactions, store-and-forward, UDP, failover, error handling, and migration from ILP and from 4.x. The [connect string reference](/docs/connect/clients/connect-string/) and the high-availability and wire-protocol pages now note where the Node.js client's keys, defaults, and behavior differ. Clarified null handling, ordinary versus background-memory retry policies, HTTP transaction boundaries, replay deduplication, stale-lock recovery, journal capacity allowances, configuration override precedence, and reuse of existing PGWire table schemas. Also clarified cancellation and handshake deadlines, typed pool settings, row validation versus publication failures, acknowledgement error timing, and background durable-ack retries - [query_activity()](/docs/query/functions/meta/#query_activity) - Documented the `is_wal`, `memory_used`, and `memory_limit` columns - [wal_tables()](/docs/query/functions/meta/#wal_tables) - Documented the `errorTag`, `errorMessage`, and `memoryPressure` columns; `errorTag` reads `OUT OF MEMORY` after a WAL apply memory limit breach - [SHOW](/docs/query/sql/show/) - `SHOW USERS`, `SHOW GROUPS`, and `SHOW SERVICE ACCOUNTS`, including their filtered forms, gain a trailing `memory_limit` column. Clients that read these results by position need [updating](/docs/security/rbac/#memory-limit-upgrade) - [CREATE GROUP](/docs/query/sql/acl/create-group/) - Documented the `WITH EXTERNAL ALIAS` form that creates a group and its OIDC or LDAP mapping in one statement - [Kafka connector](/docs/connect/message-brokers/kafka/) - Updated for QWP with a quick start, guidance on preventing duplicates and recovering from outages, and migration steps for existing HTTP pipelines - [Kubernetes Operator](/docs/enterprise-kubernetes-operator/) - Refreshed for Operator 0.2.1 across installation, configuration, high availability, backup and restore, known limitations, troubleshooting, and the generated [API reference](/docs/enterprise-kubernetes-operator/reference/api/) - [Rust](/docs/connect/clients/rust/) and [C and C++](/docs/connect/clients/c-and-cpp/) clients - Documented the UUID byte order, which was previously unstated. `Buffer::column_uuid` takes `(lo, hi)` where `hi` is the most significant half, matching `java.util.UUID`, and the chunk setter takes the 16 bytes in canonical RFC-4122 order - [Backup and restore](/docs/operations/backup/) - The restore section no longer calls `backup.restore.timestamp` point-in-time recovery: it selects the most recent backup at or before the timestamp, and a new warning explains that a restored node with a non-empty replication object store catches up to the cluster's latest state after the restore - [Point-in-time recovery](/docs/operations/point-in-time-recovery/) - The procedure previously spread across the backup and replication setup pages consolidated into a dedicated page, with the commit-time semantics of the recovery target and the verification step spelled out - [Kubernetes Operator](/docs/enterprise-kubernetes-operator/configuration/#cold-storage) - Documented native cold storage for Operator 0.3.0: the `spec.coldStorage` block, cold-manager placement during role switches, a manager-move runbook, and the synced v0.3.0 [API reference](/docs/enterprise-kubernetes-operator/reference/api/) - [Disaster recovery](/docs/high-availability/disaster-recovery/) - Failure scenarios and the primary migration procedures moved from the setup guide to a dedicated page in the replication section - [Azure](/docs/deployment/azure/#buy-through-azure-marketplace) - Documented buying QuestDB Enterprise through Azure Marketplace with a private offer, billed on the existing Azure invoice and still deployed in your own subscription - [HORIZON JOIN](/docs/query/sql/horizon-join/) - Corrected the claim that aggregate functions are required. Without them, the result has one row per distinct combination of the selected columns, so select the left table's timestamp to get one row per event and offset. The [WINDOW JOIN](/docs/concepts/deep-dive/sql-extensions/#window-join) summary in the SQL extensions overview now states that it always aggregates, returning one row per left row. The [JOIN](/docs/query/sql/join/#time-series-joins) reference and each time-series join page now link to a [guide to choosing between them](/blog/questdb-time-series-joins-guide/) ## August 2026 ### Releases - [10.0.1](https://questdb.com/release-notes/) - Released August 24, 2026 - [10.0.0](https://questdb.com/release-notes/) - Released August 6, 2026 ### QuestDB Enterprise Releases - [4.0.0](https://questdb.com/release-notes/) - Released August 25, 2026 ### New - [SWITCH ROLE](/docs/query/sql/switch-role/) - New reference page for switching a QuestDB Enterprise node between the primary and replica roles in place, with `SWITCH STATUS`, the timeout semantics, the statement errors, and the `SWITCH ROLE` permission - [Failover and role switch](/docs/high-availability/failover/) - Operator guide for planned switchovers and promotions without a restart: prerequisites, the timeout budget, refusals and the `UNKNOWN` state, what each client protocol sees during a demote, the restart hazard, and the `GET /lifecycle` and `POST /lifecycle/switch` endpoints - [Cold storage](/docs/concepts/cold-storage/) - Historical partitions move to S3, Google Cloud Storage, Azure Blob Storage, or a filesystem store as Parquet and stay queryable with normal SQL, covering the partition lifecycle, the range-read path, the immutability boundary at `DROP LOCAL`, and the manager and refresher roles - [Operating cold storage](/docs/operations/cold-storage/) - Setup guide and runbook: preparing the object store prefix, configuring the cluster, the two-step manager handoff, remote garbage collection, cold-read metrics, backup interaction, and a troubleshooting table - [Cold storage configuration](/docs/configuration/cold-storage/) - Every `cold.storage.*` setting, covering the store connection, roles, upload, read path, garbage collection, and request timeouts - [SWITCH COLD STORAGE ROLE](/docs/query/sql/switch-cold-storage-role/) - New reference page for moving the cold storage manager role between instances at runtime, with `SWITCH COLD STORAGE STATUS`, the `FORCE` break-glass path, and the timeout semantics - [Connect](/docs/connect/overview/) - New top-level Connect section that gathers the native client libraries, the compatibility protocols (ILP, PGWire, REST), and the wire-protocol specifications under one home, with a decision table for picking a path and a per-language QWP support matrix - [Connect string reference](/docs/connect/clients/connect-string/) - Every configuration key for the native clients, with worked connect strings for common setups, a goal-to-keys recipe table, sender restart and replay semantics, and an alphabetical key index - [Wire protocols](/docs/connect/wire-protocols/overview/) - QWP specifications for client implementers, covering [ingress over WebSocket](/docs/connect/wire-protocols/qwp-ingress-websocket/), [egress over WebSocket](/docs/connect/wire-protocols/qwp-egress-websocket/), and [expected client behavior](/docs/connect/wire-protocols/qwp-client-behavior/) - [Store-and-forward](/docs/high-availability/store-and-forward/when-to-use/) - New section on client-side disk buffering: choosing between memory mode and disk-backed offload, [concepts](/docs/high-availability/store-and-forward/concepts/), [configuration](/docs/high-availability/store-and-forward/configuration/), and [operating and tuning](/docs/high-availability/store-and-forward/operating-and-tuning/) - [Client failover](/docs/high-availability/client-failover/concepts/) - How clients detect a failed primary and switch to a healthy peer using multi-host address lists, host-health classification, role filtering, and zone-aware selection, plus its [configuration](/docs/high-availability/client-failover/configuration/) - [Delivery semantics](/docs/concepts/delivery-semantics/) - At-least-once delivery, where duplicate rows arise, and how designated timestamps combine with deduplication for exactly-once outcomes - [Agents](/docs/connect/agents/) - Which protocols AI agents use to drive QuestDB, the tooling available to them, and how to grant scoped access - [Live views](/docs/concepts/live-views/) - Incrementally maintained window-function queries over a WAL table, queried like a regular table, with [CREATE LIVE VIEW](/docs/query/sql/create-live-view/), [DROP LIVE VIEW](/docs/query/sql/drop-live-view/), and the [`cairo.live.view.*` settings](/docs/configuration/live-views/) - [Notebooks](/docs/getting-started/web-console/notebooks/overview/) - Web Console notebooks that combine SQL, markdown, and charts in one tab, covering [cells](/docs/getting-started/web-console/notebooks/cells/), [charts](/docs/getting-started/web-console/notebooks/charts/), [variables](/docs/getting-started/web-console/notebooks/variables/), [live dashboards](/docs/getting-started/web-console/notebooks/live-dashboards/), and [sharing](/docs/getting-started/web-console/notebooks/manage-share/) - [MCP connection](/docs/getting-started/web-console/mcp-server/) - Connect AI coding agents to the Web Console through the `@questdb/mcp-bridge` local MCP server, with the pairing flow, the four permission levels, and the available agent tools - [Register QuestDB Parquet as Apache Iceberg tables](/docs/tutorials/questdb-to-iceberg/) - Expose Parquet partitions as Iceberg tables and query them in place from Spark, Trino, DuckDB, or PyIceberg - [ALTER TABLE REBASE WAL](/docs/query/sql/alter-table-rebase-wal/) - New reference page for rebuilding a suspended WAL table under a fresh sequencer, with its requirements and permission - [ALTER TABLE SET FORMAT](/docs/query/sql/alter-table-set-format/) - New reference page for switching a table's partition storage format between `NATIVE` and `PARQUET` - [QWP configuration](/docs/configuration/qwp/) - Server-side settings for the QWP ingestion (`/write/v4`) and query (`/read/v1`) endpoints - [Check timestamp order](/docs/cookbook/sql/time-series/check-timestamp-order/) and [Check column sort order](/docs/cookbook/sql/advanced/check-column-sort-order/) - Two cookbook recipes that detect unsorted data with `lag()`: whether a table, CSV import or external Parquet file is ordered by its timestamp, and whether one column is sorted with respect to another - [Kubernetes Operator](/docs/enterprise-kubernetes-operator/) - New manual for running QuestDB Enterprise clusters on Kubernetes, covering [installation](/docs/enterprise-kubernetes-operator/installation/), getting started on [AWS](/docs/enterprise-kubernetes-operator/getting-started/aws/) and [Azure](/docs/enterprise-kubernetes-operator/getting-started/azure/), [configuration](/docs/enterprise-kubernetes-operator/configuration/), [day-to-day operations](/docs/enterprise-kubernetes-operator/operations/operator/), [high availability](/docs/enterprise-kubernetes-operator/high-availability/), [known limitations](/docs/enterprise-kubernetes-operator/known-limitations/), and the full [API reference](/docs/enterprise-kubernetes-operator/reference/api/) - [ALTER TABLE SUSPEND WAL](/docs/query/sql/alter-table-suspend-wal/) - New reference page for deliberately stopping the WAL apply job, covering the quiescent-table use case that `REBASE WAL` requires, and the trap that writes to a suspended table succeed while staying invisible to queries until `RESUME WAL` ### Reference - Added the [`node_role()`](/docs/query/functions/meta/#node_role) function, which reports the replication role of the instance to any authenticated session - [RBAC](/docs/security/rbac/#failover-operator) - Added the `SWITCH ROLE` permission to the permissions table, a failover operator scenario, and the built-in admin's break-glass role in a replicated cluster - [Minimal HTTP server](/docs/operations/logging-metrics/#lifecycle-endpoint) - Documented the `GET /lifecycle` component snapshot and the [`http.health.check.authentication.required`](/docs/configuration/http-min-server/#httphealthcheckauthenticationrequired) setting - [Replication metrics](/docs/operations/logging-metrics/#replication-metrics) - Added `questdb_replication_pending_upload_txn` and `questdb_backup_active_at_last_demote` - [Replication configuration](/docs/configuration/database-replication/#replicationrole) - Documented that `replication.role` is the boot role, the `primary-catchup-uploads` value, and the restart hazard after an in-place switch - [Storage Policy](/docs/concepts/storage-policy/) - The `TO REMOTE` and `DROP REMOTE` stages are now enforced. Documented what each does, the requirement for a WAL table with cold storage enabled, and the warning that `DROP LOCAL` makes a partition read-only for good - Added the [`table_cold_partitions()`](/docs/query/functions/meta/#table_cold_partitions) function, which returns the remote state of every partition in a table's manifest as it walks `pending`, `live`, `sealed`, and `deleting` - [SHOW PARTITIONS](/docs/query/sql/show/#show-partitions) - Two trailing columns, `seqTxn` and `isRemotelyServed`, are appended to the result set. Tools binding columns by position must be updated - [Backup and restore](/docs/operations/backup/#cold-storage-partitions) - Documented that a backup of a database using cold storage does not contain the `data.parquet` bytes, so the backup and the object store prefix are one recovery set - [Replication overview](/docs/high-availability/overview/#cold-storage-in-a-replicated-cluster) - Documented that the cold storage manager role is independent of the primary and replica roles, that partition bytes never traverse replication, and that replicas must be upgraded first - [Cold storage read metrics](/docs/operations/logging-metrics/#cold-storage-read-metrics) - Added the fifteen `questdb_cold_chunk_*` Prometheus metrics - Added the [`storage.policy.recheck.drain.interval`](/docs/configuration/storage-policy/) configuration property - [CREATE TABLE](/docs/query/sql/create-table/#partition-format) - Added the `FORMAT { NATIVE | PARQUET }` clause to store partitions as Parquet by default on partitioned WAL tables - [REST API](/docs/connect/compatibility/rest-api/#authentication) - Merged the overlapping authentication sections into one, with basic auth (including building the `Authorization` header by hand) and Enterprise token auth - [SHOW CREATE LIVE VIEW](/docs/query/sql/show/#show-create-live-view) - Documented retrieving a live view's `CREATE` statement, alongside the `CREATE LIVE VIEW` and `DROP LIVE VIEW` [permissions](/docs/security/rbac/) - Added the [`live_views()`](/docs/query/functions/meta/#live_views) catalogue function and the `L` `table_type` discriminator to the meta functions page - Added the [`is_end_of_month()`](/docs/query/functions/date-time/#is_end_of_month) date-time function, which is leap-year aware and returns `false` for `null` - Documented the [`query.timeout`](/docs/configuration/cairo-engine/) duration key (`120s`, `1m`, `500ms`) alongside the now-deprecated `query.timeout.sec`, and how the two relate - Added the [`cairo.wal.apply.suspended.tables`](/docs/configuration/wal/) and `cairo.wal.apply.suspended.write.denied` configuration properties - [SHOW CREATE MATERIALIZED VIEW](/docs/query/sql/show/#show-create-materialized-view) - Documented retrieving a materialized view's `CREATE` statement, and alphabetized the SHOW reference page - [SHOW CREATE DATABASE](/docs/query/sql/show/#show-create-database) - Documented dumping the whole database schema as round-trippable DDL, with `INCLUDE`/`EXCLUDE` category filtering - [EXPLAIN](/docs/query/sql/explain/) - Added the `Encode sort` / `Encode sort light` plan node to the plan-node reference - [LIMIT](/docs/query/sql/limit/#null-bounds) - Documented null `LIMIT` bounds (supplied via bind variables) and their two-bound semantics - Added the [`cairo.sql.parquet.cache.memory.size`](/docs/configuration/cairo-engine/) configuration property (256 MB default), deprecating the slot-based `cairo.sql.parquet.frame.cache.capacity` - Documented [`cairo.root`](/docs/configuration/cairo-engine/) absolute-path behavior: the `conf`, `import`, `export`, `tmp`, and `.checkpoint` directories become siblings of the specified directory rather than children of the server root, so leave it at the default under Docker - [read_parquet](/docs/query/functions/parquet/#designated-timestamp) - Documented nominating a designated timestamp on a Parquet file with `TIMESTAMP()` (applied directly, on a sub-query, or on a CTE), and importing a file into a table with `INSERT INTO ... SELECT` or `CREATE TABLE AS` - [SAMPLE BY](/docs/query/sql/sample-by/#sample-units) - Documented that the count is optional and defaults to `1`, so `SAMPLE BY h` is the same as `SAMPLE BY 1h`, and that it must be a positive integer written with no space before the unit - [REST API](/docs/connect/compatibility/rest-api/#execute) - Documented `/execute` and `/validate`, which compiles a query and returns its column metadata without running it. `/exec` is now marked deprecated in favour of `/execute` - [HTTP server configuration](/docs/configuration/http-server/#circuitbreakerbuffersize) - Flagged `circuit.breaker.buffer.size` as unsupported since QuestDB 10.0.0; a config that still sets it logs an advisory, or fails to start under `config.validation.strict` - [Meta functions](/docs/query/functions/meta/#wait_wal_table) - Documented [`wait_wal_table()`](/docs/query/functions/meta/#wait_wal_table), which blocks until a WAL table's pending writes have been applied so a following read sees them, plus [`sleep()`](/docs/query/functions/meta/#sleep), [`current_data_id()`](/docs/query/functions/meta/#current_data_id) and `session_user()` - [UNION, EXCEPT, INTERSECT](/docs/query/sql/union-except-intersect/#result-column-types) - Documented result column types: a column that is `SYMBOL` on every branch stays `SYMBOL` instead of widening, which also changes the type materialized by `CREATE TABLE AS` and reported in REST response metadata - [HTTP server configuration](/docs/configuration/http-server/#httpuser) - Documented that QuestDB Enterprise fails to start when `http.user`, `http.password` or `http.password.file` is set, since those Open Source settings were never enforced by Enterprise - [markout_horizon hint](/docs/concepts/deep-dive/sql-optimizer-hints/#markout_horizon) - Documented the optimizer hint that stops a markout-curve `CROSS JOIN` from materializing and sorting its whole output - [Column alias configuration](/docs/configuration/cairo-engine/#column-aliases) - Documented `cairo.sql.column.alias.expression.enabled`, the opt-out restoring pre-9.0.0 column naming, and `cairo.sql.column.alias.generated.max.size` - [Replication configuration](/docs/configuration/database-replication/#replicationdisabledtables) - Documented `replication.disabled.tables`, a reloadable list excluding tables from replication - [IAM configuration](/docs/configuration/iam/#aclpermissionscompactionrowthreshold) - Documented the two `acl.permissions.compaction.*` settings that keep `sys.acl_permissions` from growing until replica logins slow down - [SQL extensions](/docs/concepts/deep-dive/sql-extensions/) - Recorded that `pg_class.relkind` and `information_schema.tables.table_type` distinguish tables, views and materialized views, so PostgreSQL client tools can categorise objects ### Updated - [Replication setup guide](/docs/high-availability/disaster-recovery/#migration-procedures) - Planned primary migration now points at the in-place switch; the restart-based flow is kept for older versions and the emergency migration is marked as the lossy path - [Error codes](/docs/troubleshooting/error-codes/#er005) - ER005 now covers the refusal of an in-place promotion, and ER006 the restart of a demoted node with a stale `replication.role` - Client libraries rewritten for the QWP binary protocol, unifying ingestion and streaming SQL queries under one handle: [Java](/docs/connect/clients/java/), [Python](/docs/connect/clients/python/), [Go](/docs/connect/clients/go/), [C & C++](/docs/connect/clients/c-and-cpp/), [Rust](/docs/connect/clients/rust/), and [.NET](/docs/connect/clients/dotnet/) - [Web Console](/docs/getting-started/web-console/overview/) - Documented query sharing by link and tab import/export in the [code editor](/docs/getting-started/web-console/code-editor/), custom AI providers and per-provider permission levels in [QuestDB AI](/docs/getting-started/web-console/questdb-ai/), automatic column sizing in the [result grid](/docs/getting-started/web-console/result-grid/), and the storage policy section in [table details](/docs/getting-started/web-console/table-details/) - [AI coding agents](/docs/getting-started/ai-coding-agents/) - Repositioned around the agent skill and the Web Console MCP bridge together - [Telegraf](/docs/connect/message-brokers/telegraf/#authentication) - Documented authenticating from Telegraf with the Enterprise `token` setting or the Open Source `http_headers` basic-auth equivalent - [Integrations overview](/docs/integrations/overview/) - Synced with the sidebar: added the six missing pages, moved MindsDB into Other Tools, and added a Data Ingestion cross-reference - [Parquet](/docs/concepts/parquet/) - Moved the Parquet page to Concepts and revamped it around creating tables as Parquet, in-place conversion (storage policies and `ALTER TABLE`), and export; also documented `ALTER COLUMN TYPE` on Parquet partitions and relaxed the in-place conversion constraints - [Storage engine](/docs/architecture/storage-engine/) - Reworked the three-tier storage model: local native or Parquet storage, then remote object storage - [systemd deployment](/docs/deployment/systemd/) - Reworked the systemd service guide to cover both QuestDB Open Source and Enterprise - [Time to live (TTL)](/docs/concepts/ttl/) - Documented TTL on materialized views, set with `CREATE MATERIALIZED VIEW ... TTL` or `ALTER MATERIALIZED VIEW ... SET TTL` and managed independently of the base table's TTL - [Result grid](/docs/getting-started/web-console/result-grid/) - Documented the Parquet and CSV download options in the web console result grid - [Docker Compose configuration](/docs/cookbook/operations/docker-compose-config/) - Reworked the volume-permission guidance and explained why `QDB_CAIRO_ROOT` should not be set in Docker - [QuestDB MCP server](/docs/getting-started/web-console/mcp-server/) - Renamed from "MCP connection" and reworked around when an agent actually needs an MCP server, with [AI coding agents](/docs/getting-started/ai-coding-agents/) gaining a four-option matrix covering the MCP server, the REST API, the agent skill, and the [QuestDB AI Assistant](/docs/getting-started/web-console/questdb-ai/) - [pandas](/docs/integrations/data-processing/pandas/) and [Polars](/docs/integrations/data-processing/polars/) - Rewritten around the native QWP clients, keeping the previous ILP and ConnectorX approaches as legacy; Polars now also covers the Rust `polars-ingress` and `polars-egress` crate features - [Python client](/docs/connect/clients/python/) - Documented N-dimensional `float64` numpy arrays landing in matching N-dimensional column types (other dtypes are rejected), and clarified Polars consumption: prefer `to_polars()`, with `polars.DataFrame(result)` reserved for pyarrow-free installs - [Query overview](/docs/query/overview/) - Added a client libraries section ahead of PostgreSQL, and removed the stale notice describing Parquet support as beta - [QuestDB MCP server](/docs/getting-started/web-console/mcp-server/) - Updated for the renamed MCP server: the npm package is now `@questdb/mcp-server-questdb` (previously `@questdb/mcp-bridge`) and the repository is now `questdb/mcp-server-questdb`, also reflected in [AI coding agents](/docs/getting-started/ai-coding-agents/) - [.NET client](/docs/connect/clients/dotnet/) - Documented the optional `net-questdb-client-zstd` package for `QueryClient` egress compression: the fail-fast `ConfigError` raised when `compression=zstd` is requested without it, `compression=auto` degrading silently to raw, and the trimmed and Native AOT reflection caveat. The beta notice now refers to 4.0.0 - [systemd deployment](/docs/deployment/systemd/) - `ExecStart` now depends on which archive you extracted rather than on CPU architecture, because only the `rt-` archive bundles Java while the no-JRE archive runs on system Java and needs `-p /opt/questdb/questdb.jar`. A new Startup failures section maps both common boot errors to their cause and fix - [CREATE TABLE](/docs/query/sql/create-table/#write-ahead-log-wal-settings) - Dropped the redundant `WAL` keyword from `CREATE TABLE` examples across the documentation. Partitioned tables have been WAL-enabled by default for a long time, and [SHOW CREATE TABLE](/docs/query/sql/show/#show-create-table) no longer emits the keyword either, so the documented output now matches what the server returns ## July 2026 ### QuestDB Enterprise Releases - [3.3.4](https://questdb.com/release-notes/) - Released July 31, 2026 - [3.3.3](https://questdb.com/release-notes/) - Released July 1, 2026 ### Updated - [Storage policy](/docs/concepts/storage-policy/) - Clarified stage enforcement: `TO REMOTE` is now accepted and stored but not yet enforced, `DROP REMOTE` is rejected at parse time, and the policy check interval is 5 minutes - [systemd deployment](/docs/deployment/systemd/) - Added the `jdk.internal.vm` module export to the service example ## June 2026 ### Releases - [9.4.3](https://questdb.com/release-notes/) - Released June 15, 2026 - [9.4.2](https://questdb.com/release-notes/) - Released June 9, 2026 - [9.4.1](https://questdb.com/release-notes/) - Released June 3, 2026 ### QuestDB Enterprise Releases - [3.3.2](https://questdb.com/release-notes/) - Released June 23, 2026 - [3.3.1](https://questdb.com/release-notes/) - Released June 9, 2026 - [3.3.0](https://questdb.com/release-notes/) - Released June 3, 2026 ### New - [Row-level security](/docs/cookbook/sql/advanced/row-level-security/) - New cookbook recipe for restricting row visibility per user ### Reference - Documented the column wildcard with optional `EXCLUDE` list for column-level [`GRANT`](/docs/query/sql/acl/grant/#grant-on-all-columns-of-a-table) and [`REVOKE`](/docs/query/sql/acl/revoke/#revoke-from-all-columns-of-a-table) — `GRANT SELECT ON trades(*) TO user` grants every current column, and `EXCLUDE` omits specific ones - Documented custom root CA support for the replication object store: the `ca_cert_file` and `ca_builtin_roots` [connection-string parameters](/docs/high-availability/setup/#tls-with-a-private-or-self-signed-ca) trust a private, internal, or self-signed CA for S3, Azure Blob, and GCS stores - Added [`array_agg()`](/docs/query/functions/aggregation/#array_agg) aggregate function, covering scalar and array input forms, `SAMPLE BY` with FILL, and NULL handling - Documented the [`twap()`](/docs/query/functions/aggregation/#twap) designated-timestamp limitation: the timestamp argument must be the table's designated timestamp - Added [`kurtosis()`](/docs/query/functions/aggregation/#kurtosis--kurtosis_samp), [`kurtosis_pop()`](/docs/query/functions/aggregation/#kurtosis_pop), [`skewness()`](/docs/query/functions/aggregation/#skewness--skewness_samp), and [`skewness_pop()`](/docs/query/functions/aggregation/#skewness_pop) aggregate functions for distribution shape ### Updated - [systemd service example](/docs/deployment/systemd/) - Updated the Java requirement from 17 to 25 across deployment and quick-start prerequisites - [GCP deployment](/docs/deployment/gcp/) - Reworked for VM install and aligned with the AWS and Azure guides - [Capacity planning](/docs/getting-started/capacity-planning/) - Reworked the OS configuration guidance for open file limits and `vm.max_map_count` ## May 2026 ### Releases - [9.4.0](https://questdb.com/release-notes/) - Released May 18, 2026 ### New - [Out-of-order data](/docs/concepts/out-of-order-data/) - New concept page covering O3 behavior per ingestion method, engine mechanics, write amplification (with the `table_write_amp_*` columns), tuning, and common scenarios - [Posting index and covering index](/docs/concepts/deep-dive/posting-index/) - New deep-dive on posting indexes, plus covering index documentation across `CREATE TABLE`, `ALTER TABLE`, `SHOW`, `EXPLAIN`, and schema design - [Order Flow Imbalance (OFI)](/docs/cookbook/sql/finance/order-flow-imbalance/) - Cookbook recipe using the Cont-Kukanov-Stoikov definition computed from L1 quote changes, with per-ECN and consolidated variants - [Upgrade QuestDB](/docs/operations/upgrade/) - Guide for upgrading QuestDB versions - [Table/column versioning](/docs/concepts/deep-dive/root-directory-structure/) - Added versioning info to root directory structure - [DECLARE with Grafana time range](/docs/cookbook/integrations/grafana/declare-time-range/) - Pass Grafana dashboard time range into QuestDB `DECLARE` variables ### Reference - Documented [gzip request compression](/docs/connect/compatibility/ilp/overview/) for ILP/HTTP and updated [Telegraf](/docs/connect/message-brokers/telegraf/) guidance for QuestDB 9.1.0+ - Added [`ntile()`](/docs/query/functions/window-functions/reference/#ntile), [`cume_dist()`](/docs/query/functions/window-functions/reference/#cume_dist), and [`nth_value()`](/docs/query/functions/window-functions/reference/#nth_value) window functions - Added [`regr_r2()`](/docs/query/functions/finance/#regr_r2) coefficient of determination aggregate - Fixed `timestamp_ns` valid range documentation - Added precise microsecond-grained timestamp examples for PHP clients - Fixed PIVOT syntax: removed redundant `FOR` from multiple pivot statements - Updated Python client to use `sender.new_buffer()` for buffer initialization ### Updated - [Go client](/docs/connect/clients/go/) - Rewrote for the QWP binary protocol: ingestion, the QwpQueryClient query API, store-and-forward, and failover - [Storage policy](/docs/concepts/storage-policy/) - Removed the `DROP NATIVE` stage; `TO PARQUET` now removes native files and serves reads from the Parquet file - [SQL extensions and compatibility](/docs/concepts/deep-dive/sql-extensions/) - Rewritten as the canonical SQL dialect reference covering time-series clauses and joins, query syntax conveniences, storage extensions, PIVOT vs SQL Server/PostgreSQL, JSON and UNNEST, and a full inventory of standard SQL features not supported with QuestDB equivalents. Sidebar entry moved to the top of Query & SQL Reference - [systemd service example](/docs/deployment/systemd/) - Corrected JVM argument ordering, switched to `UseParallelGC`, set `-Dcontainerized=false`, and added required setup paths - [Materialized views](/docs/query/sql/create-mat-view/) - Removed storage policy support for materialized views; use `TTL` for retention instead - [Aggregation functions](/docs/query/functions/aggregation/) - Added demo tags and updated examples with runnable queries - [LATEST ON](/docs/query/sql/latest-on/) - Added demo tags to examples - [JOIN](/docs/query/sql/join/) - Updated examples to use demo data - [GROUP BY](/docs/query/sql/group-by/) - Replaced examples with fx_trades demo queries - [DISTINCT](/docs/query/sql/distinct/) - Replaced examples with fx_trades demo queries - [CAST](/docs/query/sql/cast/) - Added demo tags to examples - [PIVOT](/docs/query/sql/pivot/) - Fixed examples to use demo server data - [Array functions](/docs/query/functions/array/) - Improved page with demo examples - [TICK syntax](/docs/query/operators/tick/) - Documented imprecise date support - [SAMPLE BY](/docs/query/sql/sample-by/) - Documented `FILL(PREV(col))` fast-path syntax and updated FROM-TO limitations for keyed queries - [Grafana integration](/docs/integrations/visualization/grafana/) - Restructured query macros section with full documentation of all five plugin macros - [Configuration reference](/docs/configuration/overview/) - Revamped into 17 dedicated per-subsystem pages with epigraph-style property listings ## April 2026 ### Releases - [9.3.5](https://questdb.com/release-notes/) - Released April 13, 2026 ### QuestDB Enterprise Releases - [3.2.5](https://questdb.com/release-notes/) - Released April 13, 2026 ### New - [Storage policy](/docs/concepts/storage-policy/) - Documentation for configuring storage policies - [UNNEST](/docs/query/sql/unnest/) - SQL reference for unnesting arrays into rows - [LATERAL JOIN](/docs/query/sql/lateral-join/) - SQL reference for lateral subqueries - [Sparkline and bar visualization functions](/docs/query/functions/visualization/) - Text-based chart functions for terminal and console output - [StructArrayExplode transform](/docs/connect/message-brokers/kafka/) - Kafka SMT for exploding struct arrays ### Reference - Added [Parquet bloom filters](/docs/query/sql/alter-table-alter-column-set-parquet/) syntax and configuration - Added [`covar_samp()`](/docs/query/functions/window-functions/reference/), [`corr()`](/docs/query/functions/window-functions/reference/), and other statistical window functions - Added `array_elem_min()`, `array_elem_max()`, `array_elem_sum()`, `array_elem_avg()` to [array functions](/docs/query/functions/array/) - Fixed alphabetical ordering and added missing functions across reference pages - Added Azure ReadWrite disk caching warning to deployment docs ### Updated - [SQL reference pages](/docs/query/sql/select/) - Replaced railroad diagrams with code-based syntax blocks across 65 SQL pages, with updated examples - [SAMPLE BY](/docs/query/sql/sample-by/) - Updated timezone bucket alignment behavior - [Parquet export](/docs/concepts/parquet/) - Added partitioning options for exports - [WINDOW JOIN](/docs/query/sql/window-join/) - Documented dynamic window boundaries - [HORIZON JOIN](/docs/query/sql/horizon-join/) - Documented multi-RHS table support - [JOIN](/docs/query/sql/join/) - Improved join documentation and reorganized page - [Web Console](/docs/getting-started/web-console/overview/) - Added table details, updated screenshots - [TTL](/docs/concepts/ttl/) - Fixed removal syntax and general improvements - [REST API `/exp` endpoint](/docs/connect/compatibility/rest-api/) - Documented timeout parameter, removed outdated warning ## March 2026 ### Releases - [9.3.4](https://questdb.com/release-notes/) - Released March 26, 2026 ### QuestDB Enterprise Releases - [3.2.4](https://questdb.com/release-notes/) - Released March 26, 2026 - [3.2.3](https://questdb.com/release-notes/) - Released March 3, 2026 ### New - [Log returns](/docs/cookbook/sql/finance/log-returns/) and [gamma scalping signal](/docs/cookbook/sql/finance/gamma-scalping-signal/) cookbook recipes ### Reference - Added [`array_sort()`](/docs/query/functions/array/#array_sort) and [`array_reverse()`](/docs/query/functions/array/#array_reverse) functions - Added TLS certificate expiration metrics to [Prometheus monitoring docs](/docs/operations/monitoring-alerting/) - Removed obsolete `cairo.sql.backup.*` configuration keys - Fixed RLE encoding supported type documentation ### Updated - [SAMPLE BY](/docs/query/sql/sample-by/) - Refreshed page with improved structure and examples - [HORIZON JOIN](/docs/query/sql/horizon-join/) - Improved examples - [Cookbook](/docs/cookbook/) - Refreshed recipes with lookback patterns, named windows, and updated schema references - [Per-column Parquet encoding and compression](/docs/query/sql/alter-table-alter-column-set-parquet/) - Comprehensive documentation for column-level settings - [Database replication](/docs/configuration/database-replication/) - GCP NFS transport and tuning updates - [Ingestion benchmarks](/docs/connect/overview/) - Updated benchmark image to Q1 2026 ## February 2026 ### Releases - [9.3.3](https://questdb.com/release-notes/) - Released February 25, 2026 ### QuestDB Enterprise Releases - [3.2.2](https://questdb.com/release-notes/) - Released February 4, 2026 ### New - [HORIZON JOIN](/docs/query/sql/horizon-join/) - Full reference page for post-trade analysis joins - Post-trade analysis recipes: markout, slippage, implementation shortfall, ECN scorecard, last-look, and VPIN - Financial indicator recipes: RSI, MACD, Stochastic, Rate of Change, ATR, Donchian Channels, Keltner Channels, Realized Volatility, OBV, Maximum Drawdown, Bid-Ask Spread - [TICK Exchange Calendars](/docs/query/operators/tick/) - Enterprise feature for market-hours-aware time intervals - [AI Coding Agents](/docs/getting-started/ai-coding-agents/) - Renamed from LLM Coding Assistants, added QuestDB agent skill documentation ### Reference - Added [`twap()`](/docs/query/functions/aggregation/#twap) aggregate function - Added [`array_build()`](/docs/query/functions/array/#array_build) function - Documented [`count(distinct)`](/docs/query/functions/aggregation/#count) syntax - Updated Java ILP client artifact - Added WAL cleaner documentation for replication ### Updated - [Named windows](/docs/query/functions/window-functions/overview/) - Support for reusable `WINDOW` clause definitions - [Parquet export](/docs/concepts/parquet/) - Fixed compression defaults, restructured page, updated `read_parquet` types - [Backup](/docs/operations/backup/) - Documented `backup.schedule.cron` format, improved scheduler visibility - [Date/time functions](/docs/query/functions/date-time/) - Page updates and corrections - [Window functions](/docs/query/functions/window-functions/overview/) - Added limitation documentation - [Database replication](/docs/configuration/database-replication/) - Added workload identity options, OrderBookToArray SMT documentation - [Kubernetes secrets](/docs/deployment/docker/) - Documented secrets-from-files for container deployments ## January 2026 ### Releases - [9.3.2](https://questdb.com/release-notes/) - Released January 28, 2026 - [9.3.1](https://questdb.com/release-notes/) - Released January 14, 2026 - [9.3.0](https://questdb.com/release-notes/) - Released January 9, 2026 ### QuestDB Enterprise Releases - [3.2.1](https://questdb.com/release-notes/) - Released January 29, 2026 - [3.2.0](https://questdb.com/release-notes/) - Released January 19, 2026 ### New - [Cookbook](/docs/cookbook/) - Collection of 40+ recipes for common SQL patterns, integrations, and operations - Capital markets recipes - Financial calculations including VWAP, Bollinger Bands, TICK/TRIN, volume analysis, and more - [TICK syntax](/docs/query/operators/tick/) - New DSL for expressing time intervals with intuitive syntax like `'$now - 1h..$now'` - [AI Assistant reference](/docs/getting-started/web-console/questdb-ai/) - Documentation for the QuestDB AI Assistant - [PIVOT](/docs/query/sql/pivot/) - SQL keyword for rotating rows into columns ### Reference - Added [`percent_rank()`](/docs/query/functions/window-functions/reference/#percent_rank) window function - Added [`arg_min()`](/docs/query/functions/aggregation/#arg_min) and [`arg_max()`](/docs/query/functions/aggregation/#arg_max) aggregation functions - Added [`length_bytes()`](/docs/query/functions/text/#length_bytes) function for byte-length of strings - Added [`rnd_symbol_zipf()`](/docs/query/functions/random-value-generator/#rnd_symbol_zipf) and weighted random generators - Added [Euclidean and geographic geo functions](/docs/query/functions/spatial/) - Extended [date arithmetic](/docs/query/operators/tick/) with sub-day units ### Updated - [Window functions](/docs/query/functions/window-functions/overview/) - Restructured into dedicated section with improved navigation, added EMA, VWEMA, and ksum() functions - [Views and materialized views](/docs/concepts/views/) - Comprehensive documentation overhaul with improved examples and clearer explanations - [Designated timestamp](/docs/concepts/designated-timestamp/) - Consolidated timestamp documentation with TICK syntax examples - [Enterprise backup](/docs/operations/backup/) - Improved documentation with clearer instructions ## December 2025 ### Releases - [9.2.3](https://questdb.com/release-notes/) - Released December 18, 2025 - [9.2.2](https://questdb.com/release-notes/) - Released December 1, 2025 ### QuestDB Enterprise Releases - [3.1.2](https://questdb.com/release-notes/) - Released December 18, 2025 - [3.1.1](https://questdb.com/release-notes/) - Released December 1, 2025 ### New - [Builtin profiler](/docs/troubleshooting/profiling/) - Documentation for QuestDB's built-in query profiler - [WINDOW JOIN](/docs/query/sql/window-join/) - SQL reference for window joins with time-based lookups ### Reference - Added [`weighted_avg()`](/docs/query/functions/aggregation/#weighted_avg), [`weighted_stddev_rel()`](/docs/query/functions/aggregation/#weighted_stddev_rel), [`weighted_stddev_freq()`](/docs/query/functions/aggregation/#weighted_stddev_freq) functions - Documented compact period syntax in [SAMPLE BY](/docs/query/sql/sample-by/) ### Updated - [Materialized views](/docs/concepts/materialized-views/) - Added `REFRESH PERIOD (SAMPLE BY INTERVAL)` compact syntax documentation - [Time-series optimizations](/docs/architecture/time-series-optimizations/) - Improved explanations ## November 2025 ### Releases - [9.2.1](https://questdb.com/release-notes/) - Released November 25, 2025 - [9.2.0](https://questdb.com/release-notes/) - Released November 13, 2025 - [9.1.1](https://questdb.com/release-notes/) - Released November 3, 2025 ### QuestDB Enterprise Releases - [3.1.0](https://questdb.com/release-notes/) - Released November 25, 2025 - [3.0.5](https://questdb.com/release-notes/) - Released November 7, 2025 ### New - [Hetzner deployment](/docs/deployment/hetzner/) - Step-by-step guide for deploying QuestDB on Hetzner Cloud - [DECIMAL datatype](/docs/query/datatypes/decimal/) - Documentation for precise decimal arithmetic - [PGWire OIDC integration](/docs/security/oidc/) - Authentication via OpenID Connect ### Reference - Added `first()` and `last()` support for additional datatypes - Added `first_not_null()` and `last_not_null()` array support ### Updated - [Parquet export](/docs/concepts/parquet/) - Complete documentation for exporting data to Parquet format - [Shared pool configuration](/docs/configuration/shared-workers/) - Updated with network, query, and write shared pool options - [SQL hints](/docs/query/sql/asof-join/#choose-the-optimal-algorithm-with-an-sql-hint) - Rewritten section on temporal join hints ## October 2025 ### Releases - [9.1.0](https://questdb.com/release-notes/) - Released October 3, 2025 ### QuestDB Enterprise Releases - [3.0.4](https://questdb.com/release-notes/) - Released October 27, 2025 ### New - [PGWire for C/C++](/docs/connect/compatibility/pgwire/c-and-cpp/) - Guide for C/C++ applications using PostgreSQL wire protocol - [Table and column naming rules](/docs/query/sql/create-table/#table-name) - Guidelines for valid identifiers ### Reference - Added `w` (week) unit to [SAMPLE BY](/docs/query/sql/sample-by/) reference ### Updated - [Architecture guide](/docs/architecture/questdb-architecture/) - Refreshed with current implementation details - [Nanoseconds](/docs/query/datatypes/overview/#timestamp-and-date-considerations) - Added nanosecond timestamp precision documentation - [`TRUNCATE TABLE`](/docs/query/sql/truncate/) - Added `IF EXISTS` clause ## September 2025 ### QuestDB Enterprise Releases - [3.0.3](https://questdb.com/release-notes/) - Released September 15, 2025 ### Updated - [Partitioning](/docs/concepts/partitions/) - Improved formatting and explanations - [Go client examples](/docs/connect/clients/go/) - Updated to v4 API ## August 2025 ### Releases - [9.0.3](https://questdb.com/release-notes/) - Released August 29, 2025 - [9.0.2](https://questdb.com/release-notes/) - Released August 15, 2025 ### QuestDB Enterprise Releases - [3.0.2](https://questdb.com/release-notes/) - Released August 29, 2025 - [3.0.1](https://questdb.com/release-notes/) - Released August 15, 2025 ### New - [Array functions](/docs/query/functions/array/) - Documentation for array manipulation functions ### Updated - [`to_timestamp()`](/docs/query/functions/date-time/#to_timestamp) - Improved documentation with more examples - [Web Console](/docs/getting-started/web-console/overview/) - Updated documentation for latest console features ## July 2025 ### Releases - [9.0.1](https://questdb.com/release-notes/) - Released July 23, 2025 - [9.0.0](https://questdb.com/release-notes/) - Released July 11, 2025 ### QuestDB Enterprise Releases - [3.0.0](https://questdb.com/release-notes/) - Released July 23, 2025 ### New - [N-dimensional arrays](/docs/query/datatypes/array/) - Comprehensive guide to multi-dimensional arrays - [Order book analytics](/docs/tutorials/order-book/) - Guide for processing order book data - [Period materialized views](/docs/concepts/materialized-views/#period-refresh) - Time-based refresh for materialized views - [ASOF JOIN TOLERANCE](/docs/query/sql/asof-join/#tolerance-clause) - Limit lookback window in temporal joins ### Updated - [ILP clients](/docs/connect/overview/) - Array support added to Python, C++, Rust, Java, and .NET clients - [WAL metrics](/docs/operations/monitoring-alerting/) - Added metrics for detecting WAL apply lag ## Earlier updates For documentation changes before July 2025, see the [git commit history](https://github.com/questdb/questdb.io/commits/main/documentation).