Gov. Jerry Brown this weekend signed legislation mandating that California law enforcement agencies collect — and make public — data on the racial makeup of all those encountered by police.

For civil rights activists, Brown's action was a big step toward protecting minorities from racial profiling.

For many in law enforcement, the measure creates a massive new bureaucratic headache that will do little to illuminate the question of whether police treat minority groups fairly.

"It's a terrible piece of legislation," said Lt. Steve James, president of the Long Beach Police Officers Assn. and the national trustee for the California Fraternal Order of Police.

Written by Assemblywoman Shirley Weber (D-San Diego) in response to fatal police shootings of unarmed black men and other people of color, the legislation will require officers to collect data on anyone they stop, including "perceived" race and ethnicity, the reason for the encounter and whether arrests were made.

Law enforcement organizations, including the state Fraternal Order of Police and the 65,000-member Peace Officers Research Assn. of California, had asked Brown to veto the bill, AB 953, arguing among other things that its reporting requirements would be burdensome to police and costly to taxpayers.