What can I do to keep export dumps under 2Gb?
Administration Tips
What can I do to keep export dumps under 2Gb? All Operating Systems have file size limits, and if export is busy generating a dump file from an enormous database, it is quite possible that it will hit the O/S file size limits, and crash out in spectacular fashion. You could try various things to get around this. For a start, don’t try doing full database exports. Instead, export one schema at a time. Alternatively, try limiting the rows being exported each time, using the QUERY parameter (see my tip on ‘How do you export particular rows from a table?’ for details). But you could also make use of the FILESIZE parameter. Here, for example, is a simple (and somewhat ridiculous!) example: EXP SYSTEM/MANAGER FILE=EXPDAT.DMP FULL=Y FILESIZE=200K
When this is run, export starts generating a dump file of the name specified. But then it fills up its allotted 200K, and prompts for a new file name, like this: … EXP-00091: EXPORTING QUESTIONABLE STATISTICS. S_WAREHOUSE 5 ROWS EXPORTED . . EXPORTING TABLE EXP-00091: EXPORTING QUESTIONABLE STATISTICS. . EXPORTING SYNONYMS EXPORT FILE: EXPDAT.DMP > …and the export actually just sits there until you type in a new name. Once you do type in a new name, it resumes and proceeds as normal, until the next 200K is fully used up, and so on. You don’t even have to sit there waiting to type in the next name: the FILE parameter can be used to specify an entire string of potential names, and export will use each of them in turn: EXP SYSTEM/MANAGER FILE=EXPDAT.DMP,EXPDAT2.DMP,EXPDAT3.DMP FULL=Y FILESIZE=200K
This time, the export process proceeds without interruption, although if you look closely at the feedback you get on the screen, you might see lines like the one here: … . EXPORTING BITMAP, FUNCTIONAL AND EXTENSIBLE INDEXES . EXPORTING POSTTABLES ACTIONS CONTINUING EXPORT INTO FILE EXPDAT3.DMP ! here it is!! . .
EXPORTING TRIGGERS EXPORTING MATERIALIZED VIEWS
Copyright © Howard Rogers 2001
10/26/2001
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What can I do to keep export dumps under 2Gb?
Administration Tips
What happens if you miscalculate and supply, as I did here, only 3 possible file names, and export needs to continue into a fourth or fifth? Well, it simply reverts to the behaviour I described earlier, freezing up as it prompts for the extra file names, and resuming when one is finally provided by you, manually. This is an incredibly useful feature, and it therefore comes as something of a disappointment to realise that it was only introduced in Oracle 8.1 (8i). If you’ve any version earlier than that, things are going to be tricky, particularly since my other suggestion about using the QUERY parameter to restrict the rows that can be exported is also only of relevance to 8i! For versions prior to 8i, your best bet is to hope that you are running on Unix, because then you can create a named pipe to which the huge, monolithic dump file can be written, with a background process gzip’ing the output from the pipe on the fly. None of which I can explain further here, since my Unix skills in this regard are practically non-existent. I suppose on NT, there is a similar possibility (never tested by me) that you could export to a compressed drive, achieving much the same ‘compress on-the-fly’ functionality. There is always, however, the hope that you might realise that putting off the upgrade to 8i (or even 9i) is becoming more and more of a non-option!
Copyright © Howard Rogers 2001
10/26/2001
Page 2 of 2