# Clearing code intelligence data

Clear all precise code intelligence data from your instance and start fresh.

## Clearing the `frontend` database

The following commands assume a connection to the `frontend` database. Refer to our guide on [`psql`](/self-hosted/how-to/run-psql) if you do not use an [external database](/self-hosted/external-services/).

If you are clearing **all** code intelligence data, then you will need to clear the metadata information in the frontend database. This will clear the high-level information about code intelligence indexes, but the raw data will remain in the `codeintel-db` database, which will also need to be cleared (see the next section).

```sql
BEGIN;
TRUNCATE
  lsif_uploads,
  lsif_uploads_audit_logs,
  lsif_uploads_reference_counts,
  codeintel_commit_dates,
  lsif_packages,
  lsif_references,
  lsif_nearest_uploads,
  lsif_nearest_uploads_links,
  lsif_uploads_visible_at_tip,
  lsif_dirty_repositories
  CASCADE;
COMMIT;
```

## Clearing the `codeintel-db` database

The following commands assume a connection to the `codeintel-db` database. Refer to our guide on [`psql`](/self-hosted/how-to/run-psql) if you do not use an [external database](/self-hosted/external-services/).

### Clearing LSIF data

Truncate the following tables to clear all LSIF-encoded information from the database. This command can be run when clearing **all** data from the instance, in which case the associated records in the `frontend` database must also be cleared.

This command can also be run after a completed [migration from LSIF to SCIP](/admin/how-to/lsif-scip-migration), in which case these tables should be empty but may retain a number of blocks containing a large number of dead tuples. Truncating these _empty_ tables acts like a `VACUUM FULL` and releases the previously used disk space.

```sql
BEGIN;
TRUNCATE
  lsif_data_metadata,
  lsif_data_documents,
  lsif_data_documents_schema_versions,
  lsif_data_result_chunks,
  lsif_data_definitions,
  lsif_data_definitions_schema_versions,
  lsif_data_references,
  lsif_data_references_schema_versions,
  lsif_data_implementations,
  lsif_data_implementations_schema_versions,
  codeintel_last_reconcile
  CASCADE;
COMMIT;
```

### Clearing SCIP data

Truncate the following tables to clear all SCIP-encoded information from the database. Only run this command if you clearing **all** data from the instance, in which case the associated records in the `frontend` database must also be cleared.

```sql
BEGIN;
TRUNCATE
  codeintel_scip_metadata,
  codeintel_scip_documents,
  codeintel_scip_documents_schema_versions,
  codeintel_scip_document_lookup,
  codeintel_scip_document_lookup_schema_versions,
  codeintel_scip_documents_dereference_logs,
  codeintel_scip_symbols,
  codeintel_scip_symbols_schema_versions,
  codeintel_scip_symbol_names,
  codeintel_last_reconcile
  CASCADE;
COMMIT;
```