Data Pump execution time

Question

I am exporting 2 tables from my database as a prelimary test before doing a full export ( as part of a server migration to an new server )
I have some concerns about the time the export took ( and therefore the time the corresponding import will take - which typically is considerably longer than the export )
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 19.87 GB
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
Processing object type TABLE_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
. . exported "SAPPHIRE"."A_SDIDATAITEM" 15.45 GB 88263813 rows
. . exported "SAPPHIRE"."A_SDIDATA" 1.775 GB 14011593 rows
Master table "SYSTEM"."EXPORT_TABLES_LIMSLIVE" successfully loaded/unloaded
Dump file set for SYSTEM.EXPORT_TABLES_LIMSLIVE is:
E:\ORACLE\PRODUCT\10.2.0\ADMIN\LIMSLIVE\DPDUMP\EXP_TABLES_LIMSLIVE.DMP
Job "SYSTEM"."EXPORT_TABLES_LIMSLIVE" successfully completed at 15:43:38
These 2 tables alone took nearly an hour to export. The bulk of the time seemed to be on the line
Processing object type TABLE_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS
Q1. Is that really the line that was taking time or was the export really working on the the export of the table on the following line ?
Q2. Will such table stats be brought in on an import ? i.e. are table stats part of the dictionary therefore part of the SYS/SYSTEM schemas and will not be brought in on the import to my newly created target database ?
Q3. Does anyone know of any performance improvements that can be made to this export / import ? I am exporting from the 10.2.0.1 source Data Pump and will be importing on a new target 11gR2 Data Pump. From experiement with the command line I have found that 10.2.0.1 does not support PARALLEL so I am not able to use that on the export side ( I should be able to use it on the 11gR2 import side )
thanks,
Jim

Answer 1

Jim,
Q1. what difference does it make knowing the difference between how long the Meta Data and the actual data takes on >export ?
Is this because you could decide to exclude some objects and manually create them before import.You asked what was taking so long. This was just a test to see if it was metadata or data. It may help us try to figure out if there is a problem or not, but knowing what is slow, would help narrow things down.
With the old exp/imp utility I sometimes manually created the tablespaces and indexes in this manner, however for Data >Pump the Meta Data contains a lot more than just tablespaces and indexes - I couldn't imagine manually creating all the >tables and grants for example. I guess you can be selective about what objects you include / exclude in the export or import >( via the INCLUDE & EXCLUDE settings ) ?No, I'm not suggesting that you change your process, just trying to figure out what is slow. Also, old exp/imp and Data Pump treat metadata and data the same way. Just to maybe clear things up - when you say content=metadata_only, it exports everything except for data. It will export tablespaces, grants, users, table, statistics, etc. Everything but the data. When you say content=data_only, it only exports the data. You can use this method to export and import everything, but it's not the best solution for most. If you create all of your metadata and then load the data, any indexes on the tables need to be maintained while the data is being loaded and this will slow down the data only job.
Q2. If I do a DATA ONLY export I presume that means I need to manually pre-create every object I want imported into my >target database. Does this mean every tablespace, table, index, grant etc ( not an attractive option ) ?Again - I was not suggesting this method, just trying to figure out what was slow. If I were to do it this way, I would run the impdp on the metadata only dumpfile, then run the import on the data only dump file.
Q3. If I use EXCLUDE=statistics does that mean I can simply regenerate the stats on the target database after the import >completes ( how would I do that ? )Yes, you can do that. There are different statistics gathering levels. You can collect them per table, per index, per schema, and I think per database. You want to look at the documentation for dbms_stats.gather...
Dean