---
source: https://iinventedlight.com/library/notes/postgres-copy-bulk-load.md
title: "Fast bulk loading in PostgreSQL with COPY"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "PostgreSQL License; prose restates cited source lines"
attribution: "Summary by iinventedlight (AI-assisted). Sources: PostgreSQL Global Development Group, PostgreSQL: Documentation: 18: COPY, PostgreSQL License; PostgreSQL Global Development Group, PostgreSQL: Documentation: 18: 14.4. Populating a Database, PostgreSQL License."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-04
status: published
checked_on: 2026-11-04
as_of: 2026-11-04
confidence: medium
untested: "No code was run for this note; only the fetched documentation pages were read."
category: coding-references
topic_area: "code-ai-eng: PostgreSQL"
tags: postgresql, copy, bulk-load, performance
sources:
  - id: S1
    title: "PostgreSQL: Documentation: 18: COPY"
    publisher: PostgreSQL Global Development Group
    url: https://www.postgresql.org/docs/current/sql-copy.html
    accessed: 2026-11-04
    license: "PostgreSQL License"
  - id: S2
    title: "PostgreSQL: Documentation: 18: 14.4. Populating a Database"
    publisher: PostgreSQL Global Development Group
    url: https://www.postgresql.org/docs/current/populate.html
    accessed: 2026-11-04
    license: "PostgreSQL License"
---
# Fast bulk loading in PostgreSQL with COPY

## Short answer
Use `COPY` instead of many INSERTs. It moves data between a table and a file (or STDIN/STDOUT) in one command and has far less overhead. For a new table: create it, COPY the data, then build indexes. [S1][S2]

```sql
COPY items (id, name) FROM STDIN WITH (FORMAT csv, HEADER true);
```

## Tips
- COPY FROM appends to whatever is already in the table. [S1]
- COPY is fastest in the same transaction as the CREATE TABLE or TRUNCATE. [S2]
- Building an index on loaded data is quicker than updating it row by row. [S2]

## Claims
- id: C1
  claim: COPY moves data between tables and file-system files.
  source: S1
  evidence: "COPY moves data between PostgreSQL tables and standard file-system files."
- id: C2
  claim: COPY FROM appends data to what is already in the table.
  source: S1
  evidence: "appending the data to whatever is in the table already"
- id: C3
  claim: Loading with COPY is almost always faster than INSERT.
  source: S2
  evidence: "loading a large number of rows using COPY is almost always faster than using INSERT"
- id: C4
  claim: COPY is fastest in the same transaction as CREATE TABLE or TRUNCATE.
  source: S2
  evidence: "COPY is fastest when used within the same transaction as an earlier CREATE TABLE"

## Sources
- [S1] PostgreSQL: Documentation: 18: COPY. PostgreSQL Global Development Group. https://www.postgresql.org/docs/current/sql-copy.html . License: PostgreSQL License. Accessed 2026-11-04.
- [S2] PostgreSQL: Documentation: 18: 14.4. Populating a Database. PostgreSQL Global Development Group. https://www.postgresql.org/docs/current/populate.html . License: PostgreSQL License. Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).