GV$PGA_TARGET_ADVICE_HISTOGRAM definition in Oracle Database 11.2
GV$PGA_TARGET_ADVICE_HISTOGRAM
select
INST_ID, -- INST_ID NUMBER
PAT_PRED * 1024, -- PGA_TARGET_FOR_ESTIMATE NUMBER
round(PAT_PRED/PAT_CURR, 4), -- PGA_TARGET_FACTOR NUMBER
decode(status, 0, 'OFF', 'ON'), -- ADVICE_STATUS VARCHAR2(3)
LOWBND * 1024, -- LOW_OPTIMAL_SIZE NUMBER
(HIBND * 1024)-1, -- HIGH_OPTIMAL_SIZE NUMBER
OPTIMAL, -- ESTD_OPTIMAL_EXECUTIONS NUMBER
ONEPASS, -- ESTD_ONEPASS_EXECUTIONS NUMBER
MPASS, -- ESTD_MULTIPASSES_EXECUTIONS NUMBER
MPASS+ONEPASS+OPTIMAL, -- ESTD_TOTAL_EXECUTIONS NUMBER
IGNORED -- IGNORED_WORKAREAS_COUNT NUMBER
from
X$QESMMAHIST