oracle - Challenge in Migrating Huge Table with LOB Data -

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we're trying migrate around 230 gb oracle ec2 hosted database rds. challenge db there 1 150gb table has lot of lob data. when try migrate data using oracle import/export (data pump) takes around 9.5hrs export 150 gb table , has lob data , 2hrs import dump rds whereas other tables migrated quickly. we're using instance highest configurations still don't see improvement in performance.

just see time difference exported 150gb dump again on ec2 , in second run took 3hrs time. please suggest me better approach reduce export/import time.

ps: tried use redgate tool identify schema , data differences between oracle databases tool failed perform comparison on huge lob tables.

quickest way found migrate large volumes of lobs follows:

extract

  • write customer extract (java) process given range of id values.
  • write non-lob data each row csv, , lob file , reference file in csv each row.
  • run many extracts in parallel (these external java processes should not blocked oracle restrictions on licence)
  • preferably wrote extract file system can "swung" between 2 servers. if possible have many of these fileystems have parallel extract processes running.

load

  • use sqlloader. has option

    image_fname filler char(80), image lobfile(image_fname) terminated eof

  • experiment direct=y - on versions (10g) found little unreliable, , got regulars crashes in project, may have improved type of load.

  • again, use parallel sql loader processes possible - might want disable constraints , indexes, or use reverse indexes reduce block contention parallel loads.

you might consider partitioning on target , parallel loading each partition.

the advantage of using "swinging" file systems eliminate network bottlenecks.

these notes general guide, not specific, , require tuning , experimentation optimal mix.


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