Phase 2.1: Sequence management

[aesslinger]

Part of the Phase 2 set of PostgreSQL-specific features beyond the built-in driver.

Problem

Sequences are fundamental to PostgreSQL — every SERIAL/BIGSERIAL column creates one — but they're currently invisible in Tabularis. Users who need to inspect a sequence's current value, reset it after a bulk import, or change its increment must drop out to raw SQL; there's no browsable representation of sequences anywhere in the UI.

Proposed approach

Add RPC methods for the sequence lifecycle, backed by pg_sequences and standard DDL:

Operation	SQL
List sequences	SELECT * FROM pg_sequences WHERE schemaname = $1
Get sequence details	SELECT * FROM pg_sequences WHERE sequencename = $1
Get current value	SELECT currval('schema.seq') or last_value from pg_sequences
Reset sequence	ALTER SEQUENCE schema.seq RESTART WITH $1
Set sequence value	SELECT setval('schema.seq', $1)
Create sequence	CREATE SEQUENCE schema.seq [INCREMENT BY ...] [START WITH ...]
Drop sequence	DROP SEQUENCE schema.seq

Frontend integration

Sequences appear in the sidebar under a "Sequences" node, at the same level as Tables/Views/Routines. Double-click opens a detail panel showing increment, min/max, start, and current value.

Security considerations

Resetting a sequence can disrupt application logic (e.g. primary-key collisions if reset below the current max row id). The frontend should show a confirmation dialog before executing a reset, not fire it on a single click.

Acceptance criteria

• List, inspect, create, alter, reset, and drop sequences work end-to-end against a live database
• Sequences are browsable from the sidebar, matching the Tables/Views/Routines pattern
• Reset requires explicit user confirmation in the frontend
• No regressions in existing Phase 1 parity tests

Tests

• test_get_sequences — lists all sequences in schema
• test_get_sequence_details — returns increment, min, max, start, current
• test_reset_sequence — verify value changes
• test_create_and_drop_sequence — lifecycle

References

• Full spec: docs/planning/03-phase-2-issue-16.md (2.1)
• Priority: Sprint 1 — high demand, straightforward
• Ships as: beta update as soon as this lands (no need to wait for the rest of Phase 2)