ODPS Information Schema

This skill is for Information Schema (IS) metadata queries ONLY. If the user's question is about DDL/DML, listing tables, or general MaxCompute usage (not IS views), do NOT use this skill — use MCP tools (list_tables, get_table_schema) or odpscmd instead.

Query MaxCompute metadata through INFORMATION_SCHEMA views for storage, cost, permission, task, and governance analysis.

Prerequisites \x3Ca name="prerequisites">\x3C/a>

MANDATORY: Every IS query MUST set namespace flag. Without it, ALL queries fail with "Table not found".

• MCP: hints={"odps.namespace.schema":"true"} in execute_sql
• odpscmd: SET odps.namespace.schema=true; before each query
• No exceptions. Applies to ALL SYSTEM_CATALOG.INFORMATION_SCHEMA.* queries.

IS views require tenant-level permission. If you get access errors, the user needs tenant-level role — see references/ram-policies.md for Policy template.

Data freshness: History views (TASKS_HISTORY, TUNNELS_HISTORY) have ~5 min delay, realtime views ~3 hours. For yesterday's data, query after 06:00 to ensure completeness.

Tenant-level vs Project-level IS: MaxCompute has two IS levels. Tenant-level (SYSTEM_CATALOG.INFORMATION_SCHEMA.*) is the default — it covers all projects under the same metadata center and is recommended. Project-level (Information_Schema.*) is per-project only, requires install package Information_Schema.systables, and is being deprecated (since 2024-03 new projects no longer auto-install). Key differences: (1) project-level has fewer views (no CATALOGS, VOLUMES, FOREIGN_SERVERS, SCHEMAS, PARTITION_ACCESS_INFO, TABLE_ACCESS_INFO, QUOTA_USAGE; has SCHEMA_PRIVILEGES which tenant lacks); (2) project-level TASKS_HISTORY has task_schema while tenant-level does NOT; (3) project-level table_catalog is always odps while tenant-level is the actual project name. See Project-level IS Adaptation for transformation rules.

For MCP configuration, see references/mcp-tools-reference.md.

Execution Channels \x3Ca name="channels">\x3C/a>

MCP preferred when mcp__maxcompute-catalog__* tools are available. Fall back to odpscmd on connection/auth errors.

See references/mcp-tools-reference.md for 15 MCP tools with routing guide.

Important Rules \x3Ca name="rules">\x3C/a>

1. Always set namespace flag — every tenant-level IS query, no exceptions. Project-level IS queries do NOT need this flag
2. Filter by ds — TASKS_HISTORY / TUNNELS_HISTORY are partitioned; always add ds filter to avoid full scan
3. No SELECT * — use explicit column names
4. Cross-metadata-center NOT supported — each region is independent
5. last_access_time is NULL for partitioned tables — use COALESCE(last_access_time, last_modified_time) or check PARTITIONS view. Also: not collected for ALGO jobs or Hologres direct reads; up to 24h delay from actual access.
6. status values — TASKS_HISTORY: Terminated (normal), Failed, Cancelled (rare). Never count Terminated as failure.
7. operate_type values — TUNNELS_HISTORY: UPLOADLOG, DOWNLOADLOG, DOWNLOADINSTANCELOG, STORAGEAPIREAD, STORAGEAPIWRITE
8. Views without time fields — COLUMNS has no time column. TABLE_PRIVILEGES/COLUMN_PRIVILEGES have no time column, only expired. These views support static snapshot only, not time-series.
9. cost_cpu / cost_mem are DOUBLE — unit: 100×core×seconds / MB×seconds. Convert to CU-hours: cost_cpu / 100 / 3600
10. Duration — use DATEDIFF(end_time, start_time, 'ss') (seconds). No duration_ms column exists.
11. Non-existent fields trap — see Critical Column Reference below
12. JOIN IS views requires 3-field key — when joining any two IS views, the ON condition MUST include table_catalog, table_schema, AND table_name. Missing any one causes incorrect results in multi-catalog environments

Project-level IS Adaptation \x3Ca name="project-level-adaptation">\x3C/a>

All SQL templates in this skill default to tenant-level syntax (SYSTEM_CATALOG.INFORMATION_SCHEMA.* + namespace flag). If the environment only supports project-level IS, apply these mechanical transformations to every generated SQL:

Example transformation:

-- Tenant-level (default):
SET odps.namespace.schema=true;
SELECT table_name, data_length FROM SYSTEM_CATALOG.INFORMATION_SCHEMA.TABLES WHERE ...

-- Project-level (after transformation):
SELECT table_name, data_length FROM Information_Schema.tables WHERE ...

When to switch: If a tenant-level query fails with Table not found (and namespace flag is correctly set), or if the user explicitly says they only have project-level IS, apply the transformation rules above to all subsequent queries.

Critical Column Name Reference \x3Ca name="column-reference">\x3C/a>

For verified query examples using these columns, see references/verified-queries.md.

Routing Index \x3Ca name="routing">\x3C/a>

SKILL.md contains critical column names and namespace rules. Load sub-files only when needed:

• If multiple rows match, load ALL matched files. E.g., a non-English term causal query needs both terminology.md and playbooks+causal-templates.
• If SKILL.md inline info (tables below) is sufficient, do NOT load extra files.
• NOT about IS views? → This skill is not applicable. Use MCP tools (list_tables, get_table_schema, execute_sql) or odpscmd for DDL/DML/general queries.

Anti-pattern: Do NOT load extra files for these

\x3C!-- SYNC: derived from references/joins.md paths #1 #2 #3 #4 #5 #8 #10 -->

Inline Join Conditions (for 2+ view JOINs)

When joining IS views, you MUST include table_catalog, table_schema, AND table_name in join conditions. Common join paths:

For all 16 join paths, see references/joins.md. The 7 most common paths are inlined below.

\x3C!-- SYNC: derived from references/terminology.md — metric terms: storage usage, task CPU consumption, task execution duration, CU-hours, queue wait; dimension terms: zombie tables; metric: task failure rate -->

Inline Terminology Mapping (common non-English terms)

For all 59 terms, see references/terminology.md.

Error Recovery \x3Ca name="error-recovery">\x3C/a>

Core Views \x3Ca name="core-views">\x3C/a>

For all 31 views with complete field definitions, see references/views-reference.md. Views marked ⚠️ are tenant-level only (not available in project-level IS).

Additional Resources \x3Ca name="resources">\x3C/a>

• references/views-reference.md — Complete field definitions for all 31 IS views
• references/verified-queries.md — 30 pre-validated SQL query templates (including smoke test)
• references/entities.md — Entity-to-table mapping
• references/metrics.md — Metric definitions with SQL expressions
• references/joins.md — Join paths between views
• references/playbooks.md — 23 diagnostic scenario playbooks
• references/causal-templates.md — Root-cause analysis templates
• references/terminology.md — 59-term synonym dictionary for NL2SQL
• references/ram-policies.md — Tenant permission setup and Policy template
• references/mcp-tools-reference.md — 15 MCP tools with routing guide + MCP setup + installation
• scripts/odps_is_query.sh — CLI query tool (16 query types + custom, including smoke-test). Supports -t \x3Cseconds> for timeout (default 300s), -d YYYYMMDD for date, -p for project. Custom mode only allows SELECT (DDL/DML rejected).
• references/TROUBLESHOOTING.md — 7 error scenarios with fix templates (T1–T7)

Official Documentation \x3Ca name="docs">\x3C/a>

• MaxCompute Tenant-level Information Schema