doris-best-practices

name	doris-best-practices
description	Apache Doris table design and cluster sizing best practices. MUST USE when writing, reviewing, or optimizing Doris CREATE TABLE statements, partition/bucket strategies, data models, or cluster configurations. ALSO MUST USE whenever the doris-architecture-advisor skill produces DDL — apply the Pre-Flight Checklist to every CREATE TABLE before output. Also triggers on any workload design involving: IoT, analytics, dashboard, CDC, time-series, log analysis, real-time warehouse, point query, data platform, or any scenario where table design decisions are being made. Also triggers on replacing or migrating from legacy analytics/search/serving stacks such as Impala, Kudu, Elasticsearch/ES, Greenplum, Presto, HBase, Hive, Hadoop, Redis, or Lambda-style multi-engine data platforms, even when Apache Doris is not named explicitly. Also use when user provides an Apache Doris connection string or asks to get started. Also triggers on slow query investigation, query profiling, runtime performance diagnosis, tablet skew analysis, and table health checks — any scenario where runtime evidence (profile output, tablet distribution) informs optimization. Cluster lifecycle, billing, and networking are managed-service operations, out of scope here — use your platform's cluster-management console for those.
license	Apache-2.0
metadata	{"author":"tomz-alt","version":"0.1.0"}

Apache Doris Best Practices

Problem-first table design intelligence for Apache Doris. 37 rules, 7 use case templates, 4 sizing guides. All details in references/ directory.

---

1 ▸ Problem-First Routing

I need to build…

Problem	Template(s)	Key Rules
Real-time log/event analytics	usecase-log-event	DUPLICATE, RANGE partition, dynamic TTL, ZSTD
CDC / MySQL sync to Doris	usecase-cdc-sync	UNIQUE MoW, sequence_col, HASH bucket
Dashboard with pre-aggregated metrics	usecase-dashboard-metrics	AGGREGATE, BITMAP_UNION, sync MV
User-facing API with low-latency point queries	usecase-point-query	UNIQUE MoW, store_row_column, BloomFilter
Star schema with JOIN-heavy analytics	usecase-star-schema-join	Colocation, same bucket key/count
Small dimension / lookup table	usecase-dimension-lookup	DUPLICATE, RANDOM bucket, 3 buckets
Observability (logs + traces + metrics)	usecase-observability	3 tables: DUP logs, DUP traces, AGG metrics
Vehicle/fleet tracking	usecase-log-event + usecase-point-query	Time-series + point-query hybrid
E-commerce order analytics	usecase-star-schema-join + usecase-dashboard-metrics	Star schema + AGG rollups
Full-text search / content search	schema-index-text-search	Inverted index, MATCH, BM25
User behavior / funnel analysis	schema-types-bitmap-count-distinct	BITMAP_UNION, bitmap_intersect
Semi-structured JSON data	schema-types-variant-json	VARIANT type, schema_template

My query is slow after evidence shows…

For live slow-query or runtime diagnosis, do not use this table as the first response. First read references/cli-investigation.md and collect or attempt evidence (profile get, profile list, profile history, tablet, EXPLAIN, or auth status). Use this table only after evidence points to the symptom.

Symptom	Check These Rules	Quick Fix
Full table scan on WHERE clause	schema-keys-selectivity-first	Move filtered column to sort key position 1
JOINs are slow / shuffle	usecase-star-schema-join	Small dims (<1GB): broadcast + runtime filter. Large: colocation
COUNT DISTINCT is slow	schema-types-bitmap-count-distinct	Switch to BITMAP_UNION aggregation
LIKE '%keyword%' is slow	schema-index-ngram-for-like	Add NGram BloomFilter index
Point query latency too high	usecase-point-query	Enable store_row_column + Prepared Statement
Storage growing too fast	schema-partition-auto-on-demand + schema-props-compression	AUTO PARTITION + ZSTD compression + scheduled DROP PARTITION
Sync MV not being used	schema-mv-sync-rollup	Use raw columns (not date_trunc) in MV GROUP BY; unique aliases
Async MV rewrite fails	schema-mv-async-join + schema-mv-async-limits	Check State/RefreshState; query MV directly if predicate fails
Data skew / hot tablets	schema-bucket-composite-for-skew	Composite bucket key or RANDOM
Import fails / data version error	schema-mv-async-limits	Check concurrent MV refresh limit (max 3)
VARCHAR in key kills perf	schema-keys-fixed-length-types	Move VARCHAR after fixed-length types
Writes slow on UNIQUE table	schema-model-prefer-mow	Ensure MoW is enabled (not MoR)

---

2 ▸ Pre-Flight Checklist (Before Any CREATE TABLE)

Run through this checklist in order. Each step references the relevant rule:

• Data model — UNIQUE (updates?) vs DUPLICATE (append?) vs AGGREGATE (pre-agg only?) → schema-model-choose-for-workload
• Partition strategy — Time-series? AUTO PARTITION preferred. Small table? Skip. Do NOT combine AUTO with dynamic_partition. → schema-partition-*
• Bucket key + count — HASH on JOIN key. Calculate explicit count: daily_GB / target_tablet_GB. Use explicit fallback counts when volume is unknown: 3 for small dimensions, 8 for medium tables, 16-32 for large daily fact tables. → schema-bucket-*
• Sort key order — High-selectivity first, fixed-length before VARCHAR → schema-keys-*
• Data types — Native types, not STRING. DECIMAL not FLOAT. → schema-types-*
• Indexes — BloomFilter for equality, Inverted for text, NGram for LIKE → schema-index-*
• Properties — MoW enabled? Compression? Cloud mode replication_num=1? → schema-props-*
• DDL hard constraints (Apache Doris rejects DDL if any violated):
  • UNIQUE KEY + PARTITION BY RANGE → partition column MUST be in the UNIQUE KEY: UNIQUE KEY(id, dt) PARTITION BY RANGE(dt)
  • Key columns must be the FIRST N columns in schema, same order — put key cols first, non-key after. Example: UNIQUE KEY(account_id, symbol) means schema must start with account_id, symbol, ... — never place non-key columns between key columns
  • store_row_column = "true" works on UNIQUE MoW and DUPLICATE — NOT on AGGREGATE (Doris rejects AGG: "Aggregate table can't support row column"). Verified on 4.x; older versions were UNIQUE-only
  • AUTO PARTITION requires date_trunc() AND empty parens: AUTO PARTITION BY RANGE(date_trunc(col, 'day')) () — bare column name fails, missing () fails
  • Dynamic partition requires explicit PARTITION BY RANGE(col) () clause in DDL — properties alone are not enough

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2b ▸ DDL Templates (copy the closest match, customize columns)

For each CREATE TABLE, select the closest template below. Customize column names, types, bucket count, and partition settings. Do NOT write DDL from scratch.

T1: Append-only events/logs (DUPLICATE)

CREATE TABLE events (
    entity_id    VARCHAR(64)  NOT NULL,
    event_time   DATETIME     NOT NULL,
    event_type   VARCHAR(50)  NOT NULL,
    payload      VARIANT
) DUPLICATE KEY(entity_id, event_time, event_type)
PARTITION BY RANGE(event_time) ()
DISTRIBUTED BY HASH(entity_id) BUCKETS 10
PROPERTIES (
    "dynamic_partition.enable" = "true",
    "dynamic_partition.time_unit" = "DAY",
    "dynamic_partition.start" = "-90",
    "dynamic_partition.end" = "3",
    "dynamic_partition.prefix" = "p",
    "compression" = "zstd",
    "compaction_policy" = "time_series",
    "replication_num" = "1"
);

T2: Updatable with partition (UNIQUE MoW + CDC)

CREATE TABLE orders (
    order_id     BIGINT       NOT NULL,
    order_time   DATETIME     NOT NULL,
    update_time  DATETIME     NOT NULL,
    status       VARCHAR(20),
    amount       DECIMAL(18,2)
) UNIQUE KEY(order_id, order_time)
PARTITION BY RANGE(order_time) ()
DISTRIBUTED BY HASH(order_id) BUCKETS 5
PROPERTIES (
    "enable_unique_key_merge_on_write" = "true",
    "function_column.sequence_col" = "update_time",
    "dynamic_partition.enable" = "true",
    "dynamic_partition.time_unit" = "DAY",
    "dynamic_partition.start" = "-365",
    "dynamic_partition.end" = "3",
    "dynamic_partition.prefix" = "p",
    "replication_num" = "1"
);

T3: Small dimension / lookup (UNIQUE, no partition)

CREATE TABLE dim_product (
    product_id   INT          NOT NULL,
    name         VARCHAR(200),
    category     VARCHAR(50)
) UNIQUE KEY(product_id)
DISTRIBUTED BY HASH(product_id) BUCKETS 3
PROPERTIES (
    "enable_unique_key_merge_on_write" = "true",
    "replication_num" = "1"
);

T4: Pre-aggregated KPIs (AGGREGATE)

CREATE TABLE daily_kpi (
    stat_date    DATE         NOT NULL,
    dimension    VARCHAR(50)  NOT NULL,
    metric_sum   BIGINT       SUM DEFAULT "0",
    metric_max   DOUBLE       MAX DEFAULT "0",
    unique_users BITMAP       BITMAP_UNION
) AGGREGATE KEY(stat_date, dimension)
PARTITION BY RANGE(stat_date) ()
DISTRIBUTED BY HASH(dimension) BUCKETS 3
PROPERTIES (
    "dynamic_partition.enable" = "true",
    "dynamic_partition.time_unit" = "MONTH",
    "dynamic_partition.start" = "-12",
    "dynamic_partition.end" = "1",
    "dynamic_partition.prefix" = "p",
    "replication_num" = "1"
);

T5: Point query / API serving (UNIQUE MoW + row store)

CREATE TABLE user_profiles (
    user_id      BIGINT       NOT NULL,
    update_time  DATETIME     NOT NULL,
    name         VARCHAR(100),
    data         VARIANT
) UNIQUE KEY(user_id)
DISTRIBUTED BY HASH(user_id) BUCKETS 5
PROPERTIES (
    "enable_unique_key_merge_on_write" = "true",
    "function_column.sequence_col" = "update_time",
    "store_row_column" = "true",
    "light_schema_change" = "true",
    "replication_num" = "1"
);

---

3 ▸ Connection & CLI

Apache Doris speaks the MySQL protocol, so the always-available path is any MySQL-compatible client (mysql) plus SQL and the FE HTTP REST API. Some distributions also ship an optional management CLI (referred to here as doriscli) that adds ergonomic profiling and diagnostics commands — use it when your distribution provides one, otherwise use the native path.

Detect the optional CLI

Before running any queries, detect whether the CLI binary is available:

1. Check DORIS_CLI_PATH env var — if set, use that binary path
2. command -v doriscli — use from PATH
3. If none available: fall back to mysql client (see references/start-*.md)

When doriscli is available, prefer it for all operations:

Task	doriscli Command
Run SQL	doriscli sql "SELECT ..."
DDL inspection	doriscli sql "SHOW CREATE TABLE db.t"
Table/tablet health	doriscli tablet db.t (overview) or doriscli tablet db.t --detail
Profile a slow query	doriscli sql "SELECT ..." --profile → captures query_id
Get query profile	doriscli profile get <qid> or --full for complete diagnosis
Compare fast vs slow	doriscli profile diff <slow_qid> <fast_qid>
Performance trend	doriscli profile history <sql_pattern> --days 7
Test connection	doriscli auth status
Switch environment	doriscli use <name>

Runtime Query Investigation

For slow queries or runtime performance issues, read references/cli-investigation.md.

• Evidence first is mandatory: collect or attempt profile, tablet, DDL, stats, EXPLAIN, history, active-query, or connection evidence before forming hypotheses. If evidence cannot be collected locally, state that and provide the exact commands to run
• Prefer existing profiles: use profile get <query_id>, profile list, or profile history before re-executing SQL
• Proactive discovery: for vague slow-query reports, start with auth status, profile list --active, and recent profile list before asking the user for more context
• Safety gate: before running user SQL with --profile, check whether it is safe (no DDL, no mutation, no unbounded scan). For unknown, peak-hour, or expensive SQL, run doriscli sql "EXPLAIN <query>" --format json first and ask confirmation or request an existing query_id
• Hypotheses, not verdicts: diagnostic mappings are heuristics. Present evidence, likely cause, what to check next, and when the conclusion may be wrong
• If doriscli is unavailable, fall back to SQL commands listed in the reference
• Always use --format json for structured agent-readable output

Quick-start guides

• references/start-self-hosted.md — Self-hosted / BYOC / on-prem
• Cloud mode (storage-compute) connection differs only in the HTTP port (8080 vs 8030) — same guide applies

---

4 ▸ Cluster Sizing

Sizing guides are in:

• references/sizing-fe.md — FE node sizing
• references/sizing-be-integrated.md — BE sizing (integrated storage)
• references/sizing-be-cloud.md — BE sizing (cloud / storage-compute)
• references/sizing-storage-formula.md — Storage calculation formula

---

5 ▸ Rule Index by Category

Data Model — CRITICAL (4 rules)

• schema-model-choose-for-workload — DUP vs UNIQUE vs AGG decision tree
• schema-model-prefer-mow — Always MoW for UNIQUE tables
• schema-model-avoid-agg-for-updates — AGG cannot UPDATE/DELETE
• schema-model-sequence-col-for-cdc — Sequence column for out-of-order CDC

Partition Strategy — CRITICAL (4 rules)

• schema-partition-range-for-timeseries — RANGE for time-series
• schema-partition-dynamic-ttl — Dynamic partition for automated TTL
• schema-partition-auto-on-demand — AUTO for sporadic data
• schema-partition-skip-for-small — Skip partitioning under 1 GB

Bucket Strategy — CRITICAL (5 rules)

• schema-bucket-hash-vs-random — HASH for pruning, RANDOM for DUP only
• schema-bucket-high-cardinality-key — Choose high-cardinality column
• schema-bucket-composite-for-skew — Composite key to fix data skew
• schema-bucket-target-size — Target 1-10 GB per tablet
• schema-bucket-cloud-mandatory-hash — Cloud MoW requires HASH

Sort Key — CRITICAL (5 rules)

• schema-keys-selectivity-first — High selectivity first
• schema-keys-fixed-length-types — Fixed-length before VARCHAR
• schema-keys-prefix-index-limits — 36 bytes max, VARCHAR terminates it
• schema-keys-cluster-key-for-mow — Cluster key for UNIQUE tables
• schema-keys-avoid-float — No FLOAT/DOUBLE in sort key

Data Types — HIGH (5 rules)

• schema-types-native-vs-string — Native types, not STRING
• schema-types-zonemap-limitations — JSON/ARRAY disable ZoneMap
• schema-types-variant-json — VARIANT for semi-structured JSON
• schema-types-bitmap-count-distinct — BITMAP_UNION for exact count-distinct
• schema-types-doris-specifics — DATETIME precision, VARCHAR vs STRING

Indexes — HIGH (7 rules)

• schema-index-bloomfilter — BloomFilter for equality
• schema-index-inverted — Inverted for text/range
• schema-index-ngram-for-like — NGram for LIKE %pattern%
• schema-index-bitmap — Bitmap for medium cardinality
• schema-index-vector — HNSW/IVF for ANN search
• schema-index-text-search — Full-text MATCH + BM25

Query Acceleration — HIGH (3 rules)

• schema-mv-sync-rollup — Sync MV for single-table aggregation
• schema-mv-async-join — Async MV for multi-table JOIN
• schema-mv-async-limits — Operational limits (50M rows, 3 concurrent)

Table Properties — HIGH/MEDIUM (2 rules)

• schema-props-cloud-forced — Cloud mode forced properties
• schema-props-compression — LZ4 vs ZSTD compression

Caching — MEDIUM (2 rules)

• schema-cache-file-cache — File cache for cloud mode
• schema-cache-query-partition — Query and partition cache