BUFFER_ROWS

Also known as

buffer (with or without @ prefix)

Set the number of rows to buffer in the string builder before sending the response.

Syntax

@buffer_rows <count>
@buffer <count>

Or using custom parameter syntax:

@buffer_rows = <count>
@buffer = <count>

Default Value

The default value is 25 rows.

Special Values

Value	Behavior
0	Disable buffering - write response for each row
1	Buffer the entire array (all rows)
25	Default - buffer 25 rows before writing
> 1	Buffer specified number of rows before writing

Examples

Disable Buffering

Write each row immediately to the response stream:

comment on function stream_live_data() is
'HTTP GET
@buffer_rows 0';

Buffer Entire Response

Wait for all rows before sending response:

comment on function get_small_dataset() is
'HTTP GET
@buffer 1';

Large Buffer for Throughput

comment on function export_all_data() is
'HTTP GET
@buffer_rows 5000';

Small Buffer for Memory Efficiency

comment on function stream_data() is
'HTTP GET
@buffer 100';

Behavior

• Controls how many rows are buffered in the string builder before writing to the response stream.
• Applies to rows in JSON object arrays when returning records from the database.
• Buffering is more efficient than writing to the response stream for each row.
• Disabling buffering (0) can have a slight negative impact on performance.
• Higher values can have a negative impact on memory usage, especially with large datasets.

Performance Considerations

• Low values (0-10): Lower memory usage, more response stream writes, slight performance overhead.
• Default (25): Balanced trade-off between memory and performance.
• High values (1000+): Better throughput, higher memory usage per request.
• Value of 1: Entire result buffered before sending - best for small datasets where you want atomic responses.

Related

• NpgsqlRest Options configuration - Configure default buffer size
• Comment Annotations Guide - How annotations work
• Configuration Guide - How configuration works

Related Annotations

• COMMAND_TIMEOUT - Set query timeout
• RAW - Return raw text output