Thread: max_*, shared_buffers, and shared memory

max_*, shared_buffers, and shared memory

From
Erik Jones
Date:
Hey, everyone, a quick shared memory.  So,

max_connections are ~400b per connection
max_prepared_transactions are ~600b per prepared transaction
for lock management the cost is in table slots in units of ~220b  per
table slot with total table slots  = (max_locks_per_transaction +
(max_connections + max_prepared_transactions))

So, of these settings, which are accounted for as part of
shared_buffers and which result in a system shared memory request on
top of the shared_buffers setting at server start?  I ask because I
thought that they were all "on top of" shared_buffers" but the
comment in the config for max_connections mentions raising
shared_buffers to accommodate more.

Erik Jones

Software Developer | Emma®
erik@myemma.com
800.595.4401 or 615.292.5888
615.292.0777 (fax)

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