Solution : https://service.sap.com/sap/support/notes/496407 (SAP Service marketplace login required)
Key words : 
log by2=> sql error -709   performing con [dblink#1 @ 419] [dblink 0419 ] log by0=> connect, generalii  pre-installationiii installationiv  post-installation chronological summary, sql_execute create sequence ddlog_seq minvalue -2147483646 maxvalue 2147483646 increment, database-specific transactions17/jun/02 ii   check free space, ------------------------------------------------------------------------ii  pre-installation28/jan/03 installation preparation activities, log mirroring recommendations30/aug/04 iv   java, message28/jan/03 ii   installation preparation activities, /instguides -> sap web application server ->release 6, system profile fileto prevent upgrade problems, installation28/aug/03 iv   sapinst dialog instance
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