2020-07-24T11:47:30.696BEIST INFO OGG-02089 Oracle GoldenGate Capture for Oracle, xx.prm: Source redo compatibility version is: 12.2.0.
2020-07-24T11:47:30.696BEIST INFO OGG-00546 Oracle GoldenGate Capture for Oracle, xx.prm: Default thread stack size: 196608.
2020-07-24T11:47:30.696BEIST INFO OGG-00547 Oracle GoldenGate Capture for Oracle, xx.prm: Increasing thread stack size from 196608 to 1048576.
2020-07-24T11:47:30.776BEIST INFO OGG-01515 Oracle GoldenGate Capture for Oracle, xx.prm: Positioning to begin time Jul 24, 2020 11:47:22 AM.
2020-07-24T11:47:32.056BEIST INFO OGG-01516 Oracle GoldenGate Capture for Oracle, xx.prm: Positioned to (Thread 1) Sequence 57711, RBA 391389184, SCN 0.0 (0), Jul 24, 2020 11:47:22 AM.
2020-07-24T11:47:32.056BEIST INFO OGG-01515 Oracle GoldenGate Capture for Oracle, xx.prm: Positioning to begin time Jul 24, 2020 11:47:22 AM.
2020-07-24T11:47:33.038BEIST INFO OGG-00987 Oracle GoldenGate Command Interpreter for Oracle: GGSCI command (oracle): info all.
2020-07-24T11:47:33.753BEIST INFO OGG-01516 Oracle GoldenGate Capture for Oracle, xx.prm: Positioned to (Thread 2) Sequence 57648, RBA 272661520, SCN 0.0 (0), Jul 24, 2020 11:47:22 AM.
2020-07-24T11:47:33.754BEIST INFO OGG-01515 Oracle GoldenGate Capture for Oracle, xx.prm: Positioning to begin time Jul 24, 2020 11:47:22 AM.
2020-07-24T11:47:38.142BEIST INFO OGG-00987 Oracle GoldenGate Command Interpreter for Oracle: GGSCI command (oracle): info all.
2020-07-24T11:47:54.198BEIST ERROR OGG-00446 Oracle GoldenGate Capture for Oracle, xx.prm: error retrieving redo log sequence for begin time 2020-07-24 11:47:22.000000Not able to establish initial position for begin time 2020-07-24 11:47:22.000000.
2020-07-24T11:47:54.198BEIST ERROR OGG-01668 Oracle GoldenGate Capture for Oracle, xx.prm: PROCESS ABENDING.

extract参数：
GGSCI (xxdb1) 1> edit params xx

EXTRACT xx
setenv(ORACLE_HOME="/u01/app/oracle/product/12.2.0/dbhome_1")
setenv(NLS_LANG=“AMERICAN_AMERICA.AL32UTF8”)
setenv(ORACLE_SID=“xxdb1”)
userid xx,password xxxxx
GETTRUNCATES
REPORTCOUNT EVERY 1 MINUTES, RATE
TRANLOGOPTIONS DBLOGREADER
DISCARDFILE /home/oracle/ogg/dirrpt/xx.dsc, APPEND, MEGABYTES 1000
WARNLONGTRANS 2h,CHECKINTERVAL 300
EXTTRAIL /home/oracle/ogg/dirdat/xx/ex
DBOPTIONS ALLOWUNUSEDCOLUMN
REPORTROLLOVER AT 02:00
GETUPDATEBEFORES
NOCOMPRESSDELETES
NOCOMPRESSUPDATES
TABLE xx.xx;

数据库环境为12.2.0.1多节点rac，asm，
ogg为123014，在单节点部署
归档日志都存在，但是抽取失败，不能有效获取scn，不知道为何；通过连接asm获取也都是一样的报错信息