I have found that large table exports are much easier than imports, set direct=y, do the export on the local server, then copy the export to your destination server to do the import. Also, if you build the indexes as a separate import job it works better. For best performance, here is what I found worked best, Do all of this with multiple streams: Export the tables, (rows=n) to get your table definitions. export rows=y, direct=y to get the data Import the table definitions (rows=n, constraints=n, indexes=n). Import the tables, constraints=n and indexes=n, rows=y Then import again, rows=n indexes=y constraints=y On Tue, Mar 25, 2008 at 9:15 AM, Howard Latham <howard.latham@xxxxxxxxx> wrote: > I found that large tables and exp are difficult. also exp/imp means you > have to rebuild the indexes - > that aint arf slow - even for a small db! > > > On 25/03/2008, Andrew Kerber <andrew.kerber@xxxxxxxxx> wrote: > > > > It can be done with export import. If you use export import, use > > multiple streams, and disable all constraints before the import. Enable the > > constraints when all imports are complete. That includes primary key > > constraints. It takes planning and practice to use that method, but it will > > work. The advantage is that most DBA's have a good understanding of > > exp/imp. > > > > Datapump will also work. Datapump will run in parallel mode, but it has > > some bugs in 10g. > > > > If you have blobs/clobs they will be your single largest time consumer. > > If you use export/import do not commit until all the blobs/clobs are > > imported. I have done this a few times, and at one point I wrote something > > for a mass delete using an export (basically, export the rows to keep, > > truncate the table, and import). It was nice since it rebuilt the table and > > indexes at the same time it did the export/import. > > > > On Tue, Mar 25, 2008 at 6:56 AM, Sandra Becker <sbecker6925@xxxxxxxxx> > > wrote: > > > > > Source DB: Dell server, RHEL4, 12G RAM, Oracle 64 bit 126.96.36.199 SE1, > > > little endian > > > Target DB: IBM VM on series z9, SLES10, 4G RAM, Oracle 10.2.0.3 EE, > > > big endian > > > Database is just shy of 1 terabyte in size--70 percent of data is in a > > > single table; total of 212 tables. > > > 12 very large tables, including the monster--most have no column, like > > > a static date, that can be used to logically break the data into > > > "partitions". > > > > > > I'm working on procedures to move our production database from the > > > Dell to the IBM. My tests so far indicate that I'm going to need more > > > than > > > 24 hours. Management, in their infinite wisdom, is insisting that it be > > > done in less than 8. It will take as long as it takes, but I'm wondering > > > what I can do to speed things up. So far I've done the following: > > > > > > 1) exp/imp - too slow overall > > > 2) plsql that commits at regular intervals, depending on the size of > > > the table - works very well for all tables under 1M; can load 111 tables > > > in > > > under 2 hours using 2 concurrent sessions. Works for larger tables, but > > > obviously takes much longer. I had 2 sessions doing tables under 1M and 2 > > > doing tables between 1M and 100M concurrently. Didn't try for the 12 > > > tables > > > over 100M. > > > 3) Direct-path insert - used on the table holding 70 percent of the > > > data. Four months ago I insisted this table have a static date column > > > added. I can logically break the data loads down by date--they want the > > > most current data loaded first, the remainder can be done over a period of > > > days. This is working reasonably well, but having done this same thing > > > once > > > before on this table, I know it will take about a month to get all the > > > data > > > moved based on the constraints I'm working under--can't be done during > > > core > > > business hours, etc. > > > 4) I put the target database in noarchivelog mode for my testing. Is > > > this a wise move for migrating production during the go live? > > > > > > Manage has suggested that I leave off old data and load it later. > > > Doesn't work with 95 pecent of the tables because of their structure and > > > foreign key constraints. They also suggested I use both the primary and > > > the > > > standby databases to read from. No way to test this until I go > > > live--constraints again--although this actually was part of my plan from > > > the > > > beginning. Will too many concurrent sessions loading data slow things > > > down > > > too much? What would I look at to determine this? 10g is new to me so > > > I'm > > > not familiar with all the features yet and may be missing something > > > significant. > > > > > > Any suggestions are appreciated, other than telling management what > > > they can do with their time constraint. (Already did that.) > > > > > > Thanks. > > > > > > Sandy > > > > > > > > > > > -- > > Andrew W. Kerber > > > > 'If at first you dont succeed, dont take up skydiving.' > > > > > -- > Howard A. Latham > -- Andrew W. Kerber 'If at first you dont succeed, dont take up skydiving.'