SINGAPORE - A pub owner pumped his fist and shed tears of relief after he was sentenced to four years' jail on Friday for fatally stabbing a drunk and violent patron who started a brawl.

Prosecutors had sought at least 12 years' jail and caning for Low Chuan Woo, 45, arguing that his actions were "wholly disproportionate" even though it was the patron, Mr Mohamed Iskandar Ishak, 45, who started the fight.

But High Court judge Tay Yong Kwang accepted the defence's arguments that Low acted in self defence because Mr Iskandar, who was 37kg heavier, was behaving aggressively.

The judge did not impose caning on Low, who pleaded guilty to culpable homicide. He said Low was minding his own business when Mr Iskandar started the unfortunate chain of events that led to his own death in January last year.

"With the deceased behaving the way that he did that night... it was not surprising that the accused eventually felt he had no choice but to arm himself," said Justice Tay. The only "wrong and foolish" thing Low did that night was to grab a knife from the pub after he escaped from Mr Iskandar's grip and returned to confront the patron with it, said the judge.

Low was also jailed an additional eight months on separate charges relating to him running the Changi Village pub, Ramesses Entertainment, as a brothel and living on immoral earnings.

He knew that the Filipino "performing artists" working at the pub provided sexual services to customers and took a 50 per cent cut of their earnings from these services.