By name: pg_dump description: Consult PostgreSQL's pg_dump implementation for guidance on system catalog queries and schema extraction when implementing pgschema features. Use this skill when adding new schema object support, debugging inspector.go queries, understanding how PostgreSQL represents objects internally, or handling version-specific features across PostgreSQL 14-18.
pg_dump Reference
Reference pg_dump's implementation for correct system catalog queries and schema extraction patterns.
Source
Repository: https://github.com/postgres/postgres/blob/master/src/bin/pg_dump/
Key files:
pg_dump.c- Main implementation with all system catalog queriespg_dump.h- Data structurespg_dump_sort.c- Dependency sortingcommon.c- Shared catalog query utilities
Object Type → pg_dump Function → System Catalogs
| Object | Function | Catalogs |
|---|---|---|
| Tables & Columns | getTables() |
pg_class, pg_attribute, pg_type |
| Constraints | getConstraints() |
pg_constraint |
| Indexes | getIndexes() |
pg_index, pg_class |
| Triggers | getTriggers() |
pg_trigger, pg_proc |
| Functions | getFuncs() |
pg_proc |
| Views | getViews() |
pg_class, pg_rewrite |
| Sequences | getSequences() |
pg_sequence, pg_class |
| Policies | getPolicies() |
pg_policy |
| Types | getTypes() |
pg_type |
| Aggregates | getAggregates() |
pg_aggregate, pg_proc |
| Comments | getComments() |
pg_description |
Key Helper Functions
pg_get_expr(expr, relation, pretty)- Deparse expressions (defaults, WHEN clauses, index predicates)pg_get_constraintdef(oid, pretty)- Get constraint DDLpg_get_indexdef(oid, column, pretty)- Get index DDLpg_get_triggerdef(oid, pretty)- Get full trigger DDL
Important: For trigger WHEN clauses, always use pg_get_expr(t.tgqual, t.tgrelid, false) from pg_catalog.pg_trigger. Do NOT use information_schema.triggers.action_condition.
Workflow
- Identify the object type you're implementing
- Find the pg_dump function from the table above
- Read the system catalog query — note which columns, joins, and helper functions are used
- Check version-specific handling — pg_dump uses
fout->remoteVersionchecks - Adapt for pgschema in
ir/inspector.goorir/queries/:- Use pgx parameter binding
- Handle NULLs appropriately
- Add version detection if needed
When pg_dump is Authoritative
Always reference for: system catalog query patterns, correct use of pg_get_* functions, version-specific feature detection, object dependency tracking.
When NOT to Copy pg_dump
Don't copy: output formatting (pgschema has different conventions), archive/restore logic, full-database scope (pgschema is schema-focused), pre-PG14 compatibility.
pgschema Adaptation Pattern
// pg_dump query pattern:
// SELECT t.tgname, pg_get_expr(t.tgqual, t.tgrelid, false) as when_clause
// FROM pg_catalog.pg_trigger t WHERE ...
// pgschema adaptation (in ir/inspector.go or ir/queries/):
query := `SELECT t.tgname, pg_get_expr(t.tgqual, t.tgrelid, false)
FROM pg_catalog.pg_trigger t
WHERE t.tgrelid = $1 AND NOT t.tgisinternal`
rows, err := conn.Query(ctx, query, tableOID)