> What is PSP process? Note:331000.1 says > "PSP stands for Process SPawner and this process has the job of creating and managing other Oracle processes. > NOTE: There is no documentation currently in the Oracle Documentation set on this process." > But it doesn't say what those "other Oracle processes" are. On 10gR2 and up running on Linux, background processes have an environment variable SKGP_HIDDEN_ARGS. On 10gR2, I believe the 7th part of the value tells us which process spawns this process. (On 11g and 12c, it's the 8th.) For example, checking arc0: $ ps eww $(pgrep -f ora_arc0_$ORACLE_SID) | perl -nle 'print $& if /SKGP_HIDDEN_ARGS=[^ ]+/' SKGP_HIDDEN_ARGS= $ ps -fp 8623 UID PID PPID C STIME TTY TIME CMD oracle 8623 1 0 Nov08 ? 00:00:25 ora_psp0_oracd2 See http://yong321.freeshell.org/computer/OracleViewedFromOS.doc for more info. Most background processes are spawned by this PSP process. On a 12.1.0.2 server: $ for i in $(ps -u oracle -opid=); do echo $i; ps eww $i | perl -nle 'print $& if /SKGP_HIDDEN_ARGS=[^ ]+/'; done 658 SKGP_HIDDEN_ARGS= 2859 3075 SKGP_HIDDEN_ARGS= 3077 SKGP_HIDDEN_ARGS= 3079 SKGP_HIDDEN_ARGS= 3081 SKGP_HIDDEN_ARGS= 3624 3765 SKGP_HIDDEN_ARGS= 6964 SKGP_HIDDEN_ARGS= 10164 SKGP_HIDDEN_ARGS= 13231 SKGP_HIDDEN_ARGS= 15409 15410 15880 SKGP_HIDDEN_ARGS= 15882 SKGP_HIDDEN_ARGS= 15884 ... $ ps -fp 15882 UID PID PPID C STIME TTY TIME CMD oracle 15882 1 0 Sep22 ? 00:04:58 ora_psp0_sand12c