Difference in database size

Posted by vithal.kattikar@hgst.com on 17-Nov-2015 22:58

Hi All,

Good Day.

Currently we have database in 10.1C progress version on HP-UX , we are planning to move to progress 11.5 on 

Linux OS.

Since it includes Progress and hardware migration I created database with below steps.

1.prostrct create <db-name> db-name.st (FTP ed .st file from HP-UX to Linux machine)

2.procopy /usr/dlc115/empty8 <db-name>

3.Took all ..df and .d files from HP-UX and loaded into linux server .

So new database are created now. But when I check for DB size with Promon <db-name> and chosing Option 5.

there is difference in the database size.

Database Name  HP-UX DB SIZE                     LINUX-DB SIZE

symglbl                 1461MB                                     781MB

SSOEM                7052 MB                                      5130 MB

So after seeing the this difference , I am worried whether my new database on linux machine are accurate or not.

Please provide your thought on this.

Please let me know how can I do some test to ensure my new database on linux are same as that of database on HP-UX. 

All Replies

Posted by Rob Fitzpatrick on 17-Nov-2015 23:22

A dump and load procedure should always include a verification of record counts from tabanalys or dbanalys reports from the source and target databases to ensure all tables are accounted for and have equal record counts.  Check that first.  

Also, and this is less about the size difference and more about best practice, ensure that any other required data in the source databases (_User records, _sec-* records, SQL permissions, current sequence values) has been dumped and loaded as well.

Depending on the state of the source databases, it is possible that just the act of dumping and loading and rebuilding the indexes reduced the overall size of the databases by the amount you have measured.

Posted by vithal.kattikar@hgst.com on 18-Nov-2015 00:48

Hi Rob,

I ran dbanalys on both hp-ux and linux database. I compared the record count column and it looks both have the same number of records .

I have loaded other stuffs like

slq-views

user table contents

security permisssion

sequence current values

Database Identification Properties

Database Options into linux database .

Then shall I asssume that database in hp-ux and database in linux are identical. Please provide your thought

Posted by George Potemkin on 18-Nov-2015 01:03

Did you compare index size (BTW, did you binary D&L + idxbuild)?

Did you compare free space?

Did you compare % of the RM block space is used?

Posted by vithal.kattikar@hgst.com on 18-Nov-2015 01:07

Hi George,

I used data dictionary to perform Dump and load .

Can u please tell where i can check for free space and % RM block space used?

Posted by George Potemkin on 18-Nov-2015 01:35

"RECORD BLOCK SUMMARY" segment ends by the messages like:
2046047 RM block(s) found in the database.
97.91% of the RM block space is used.

Dbanalys ends by "DATABASE BLOCK ANALYSIS" segment with the messages like:
42188 free block(s) found in the database.
85 empty block(s) found in the database.
2579804 total blocks found in the database.

Posted by ChUIMonster on 18-Nov-2015 07:24

There are many reasons why the "size" shown in PROMON might differ.  Two really big potential reasons would be changes in the rows per block and storage area type.  Those might be deliberate changes or accidental changes.  I suggest that you compare the .st file from HPUX to the .st file on Linux.  Get current .st files using "prostrct list".

Posted by Dmitri Levin on 18-Nov-2015 11:05

Do not compare the size using promon. Since you did dbanalys on both hp-ux and linux databases, compare those sizes. They should match a little better. And new database on linux should be smaller. All indexes were compacted ( rebuilt ). The unique indexes could shrink several times, I have seen 25:1 ratio index shrink after big table purge. It is actually very much recommended to do idxcompact after a purge. You could also have big RM chains in old database, that was taken care during D&L.

And finally compare the speed that dbanalys took on hp-ux vs linux. I bet it was much faster on new db. And thus database will work faster too.

Posted by George Potemkin on 18-Nov-2015 11:21

> And finally compare the speed that dbanalys took on hp-ux vs linux. I bet it was much faster on new db. And thus database will work faster too.

A bit disagree. Indeed an application and dbanalys can run faster after D&L but in the different degree. And an application can work slower after D&L. Also it's important to differ the online and offline dbanalys. Their times may significanly differ one from another.

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