one of the documented procedures in this installation of the ACS
ad_partner_memoize_list_from_db   sql_query   var_list   { divider "" }   { also_memoize_as "" }
What it does:
Allows you to memoize database queries without having to grab a db handle first. If the query you specified is not in the cache, this proc grabs a db handle, and memoizes a list, separated by divider inside the cache, of the results. Your calling proc can then process this list as it normally. Each var in var_list is simply appended as a single element to the list that is eventually returned.
Defined in: /web/philip/tcl/ad-partner-defs.tcl

Source code:

    ns_share ad_partner_memoized_lists

    set str ""
    if { [empty_string_p $divider] } {
	# Users probably will never have this character (we hope)
	set divider [ad_partner_default_divider]

    if { [info exists ad_partner_memoized_lists($sql_query)] } {
	set str $ad_partner_memoized_lists($sql_query)
    } else {
	set db [ns_db gethandle subquery]
	set selection [ns_db select $db $sql_query]
	while { [ns_db getrow $db $selection] } {
	    foreach var $var_list {
		if { ![empty_string_p $str] } {
		    append str $divider
		append str [expr $$var]
	ns_db releasehandle $db
	set ad_partner_memoized_lists($sql_query) $str
    if { ![empty_string_p $also_memoize_as] } {
	set ad_partner_memoized_lists($also_memoize_as) $str
    return [split $str $divider]