diff

Runs a full comparison of both schema and data between the production and development databases. This is the read-only analysis step — it writes reports but makes no changes to either database.

Usage

deepdiffdb diff --config deepdiffdb.config.yaml

What It Does

1. Introspects the schema of both databases (same logic as schema-diff).
2. For every table with a matching schema in both databases: hashes each row using SHA-256 (excluding ignored columns) and compares the hash maps.
3. Classifies each row difference as: added (in dev only), removed (in prod only), or updated (exists in both, different values).
4. Identifies conflicts — rows where the primary key exists in both databases but the values differ in a way that requires a resolution decision.
5. Writes all reports to output.dir.

Tables with schema drift are skipped for data diffing and flagged in the report.

Flags

Flag	Description
--config	Path to the configuration file (default: deepdiffdb.config.yaml)
--html	Generate an interactive HTML report (report.html) in addition to JSON/text outputs
--batch-size N	Rows per keyset-paginated query (overrides performance.hash_batch_size)
--parallel N	Max tables hashed concurrently (overrides performance.max_parallel_tables)
--verbose	Enable debug-level logging
--log-level	Minimum log level: debug, info, warn, error (default: info)
--log-format	Log output format: text or json (default: text)
--log-file	Write logs to this file in addition to stdout

Output Files

All files are written to output.dir (default: ./diff-output).

File	Description
schema_diff.json	Machine-readable schema differences
schema_diff.txt	Human-readable schema diff
content_diff.json	Row-level differences: added, removed, updated rows per table
conflicts.json	Rows that exist in both databases with conflicting values
summary.txt	High-level statistics: tables scanned, rows added/updated/removed, conflict count
report.html	Interactive HTML report (only when --html is used)

Example

# Basic diff
deepdiffdb diff --config deepdiffdb.config.yaml

# With HTML report and streaming flags for large tables
deepdiffdb diff --config deepdiffdb.config.yaml --html --batch-size 5000 --parallel 4

Example summary.txt:

Schema: 1 table modified (orders), 1 table added (invoices)
Tables scanned: 8
  Tables with data diff: 3
  Tables skipped (schema drift): 1

Row differences:
  Added  : 24
  Removed: 2
  Updated: 11

Conflicts: 3

Performance Notes

For tables with millions of rows, use --batch-size and --parallel to control memory usage and throughput. See Streaming Large Datasets for tuning guidance.