Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 2
तदभिज्ञोऽपि भगवान् सर्वात्मा सर्वदर्शन: । प्रश्रयावनतोऽपृच्छद् वृद्धान् नन्दपुरोगमान् ॥ २ ॥
tad-abhijño ’pi bhagavānsarvātmā sarva-darśanaḥpraśrayāvanato ’pṛcchadvṛddhān nanda-purogamān
Being the omniscient Supersoul, the Supreme Lord Kṛṣṇa already understood the situation, yet He still humbly inquired from the elders, headed by His father, Nanda Mahārāja.
Lord Kṛṣṇa was eager to enact His pastime of lifting Govardhana Hill and defeating the false pride of Indra, and thus He cleverly inquired from His father about the imminent sacrifice.