Questions about guc units

Hi hackers,
I have some questions about guc units, new feature in 8.2.

#shared_buffers = 32000kB # min 128kB or max_connections*16kB
#temp_buffers = 8000kB # min 800kB
#effective_cache_size = 8000kB

Are there any reasons to continue to use 1000-unit numbers? Megabyte-unit
(32MB and 8MB) seems to be more friendly for users. It increases some amount
of values (4000 vs. 4096), but there is little in it.

#max_fsm_pages = 1600000 # min max_fsm_relations*16, 6 bytes each
#wal_buffers = 8 # min 4, 8kB each

They don't have units now, but should they have GUC_UNIT_BLOCKS and
GUC_UNIT_XLOG_BLCKSZ unit? I feel inconsistency in them.

Regards,
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ITAGAKI Takahiro
NTT Open Source Software Center