Temporarily Changing Session‑Level Parameters in GBase 8a

Some parameters in GBase 8a can be modified at the session level, affecting only the current connection. When using connection pools, it's a good practice to save the original value, apply the temporary change, and restore it afterwards to avoid impacting subsequent queries. Here's the safe workflow for a gbase database.

Steps

1. Save the current value – Use SELECT @@parameter_name and store it in a user variable.
2. Change the parameter – Use SET parameter_name = new_value.
3. Restore the parameter – After the specific query completes, SET parameter_name = @saved_variable.

Complete Example

-- 1. Inspect and save the current value
SELECT @@estimate_func_max_len;
-- Returns 0
SET @bak = @@estimate_func_max_len;

-- 2. Temporarily change the parameter
SET estimate_func_max_len = 32700;
SHOW VARIABLES LIKE 'esti%';
-- Shows Value = 32700

-- 3. Restore the original value
SET estimate_func_max_len = @bak;
SHOW VARIABLES LIKE 'esti%';
-- Shows Value = 0

This pattern lets you tune parameters for specific queries without permanently altering the session environment, keeping your gbase database connections clean and predictable.