The psalmist tells us that he remember’s God’s name at night. Night prayer … a common idea in the Bible is set prayers at set times.
Psalm 55:18 — in the evening, in the morning, and at noonday, I will complain and lament.
Psalm 119:164 — seven times a day.
Acts 3:1, etc.
Prayer in the world of ancient Israel involved setting set times for set prayers — that’s why we have the Psalms. They faced Jerusalem, said their prayers, and then let that kind of prayer structure the day. In our psalm today, at 119:55, the psalmist announces that in his night prayers he remembers the name of God.

Remembering God’s name — as God remembers his promise (119:49) — involves invoking the God who reveals his name (YHWH), who promises to be for them all that Israel needs (Ex. 3:14), and who has entered into covenant obligation with Israel (Gen 12; 15; Exod 19-24; 2 Sam 7).
For the psalmist to “remember God’s name” is to remind God of God’s obligations to deliver and to glorify that name through salvation.