molt-verify

molt verify

Compares source and target databases for schema (DDL) and row (data) consistency. Run after molt fetch to confirm migration integrity.

Basic Structure

molt verify \
  --source "<source-conn>" \
  --target "<crdb-conn>" \
  [options]

Verification Phases

Phase 1 — Schema: Compares table presence, columns, types, NOT NULL constraints, and primary key structure.

Phase 2 — Rows (default, --rows=true): Iterates source rows in PK order and compares against target. Reports missing, extraneous, and mismatched rows per shard.

Modes

Mode	Command	Use When
Full (default)	molt verify --source "..." --target "..."	Post-migration integrity check
Schema-only	molt verify ... --rows=false	Fast DDL check; no data I/O

Concurrency & Sharding

# Default: CPU-count tables in parallel, 1 shard/table, 20k rows/batch
molt verify --source "..." --target "..."

# Large tables: parallelize within a single table
molt verify --source "..." --target "..." \
  --concurrency 1 --concurrency-per-table 8 --row-batch-size 50000

# Rate-limited (minimize production impact)
molt verify --source "..." --target "..." \
  --rows-per-second 1000 --concurrency 2

Sharding splits a table's PK range across workers. Supported PK types: INT, FLOAT, DECIMAL, UUID. Falls back to a single full-scan for unsupported types.

Common Workflows

1. Post-migration sanity check

molt verify \
  --source "postgresql://<user>:<password>@pg:5432/db" \
  --target "postgresql://root@crdb:26257/db"

2. Schema-only (CI gate)

molt verify \
  --source "..." --target "..." \
  --rows=false --non-interactive --log-file stdout

3. Filtered verification (subset of tables)

molt verify \
  --source "..." --target "..." \
  --table-filter "customers|orders"

4. Verify with column exclusions

# transformations.json: {"tables":[{"name":"users","excludedColumns":["temp_col"]}]}
molt verify \
  --source "..." --target "..." \
  --transformations-file transformations.json