RE: Table partitioning in 7.5

date: Sat, 17 Sep 2022 18:46:15 +0000
from: Rob Berendt <rob@xxxxxxxxx>
subject: RE: Table partitioning in 7.5

It is rather confusing.
You can read it here:
https://www.ibm.com/docs/en/i/7.5?topic=availability-maximum-capacities

Maximum number of tables referenced in an SQL statement 1000(8)
8 The maximum number of members (and partitions) referenced is also 1000.
In DELETE and UPDATE statements the maximum number is 256. In a complex SQL
statement, the number of tables that can be referenced may be limited by
internal structures.

Number of members that can be joined 256 members

Maximum number of members in a physical or logical file 32 767

I've not used this function yet.

Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1
Group Dekko
Dept 1600
Mail to: 7310 Innovation Blvd, Suite 104
Ft. Wayne, IN 46818
Ship to: 7310 Innovation Blvd, Dock 9C
Ft. Wayne, IN 46818
http://www.dekko.com

-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Gad
Miron
Sent: Saturday, September 17, 2022 8:38 AM
To: midrange-l@xxxxxxxxxxxxxxxxxx
Subject: Table partitioning in 7.5

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Hello sages

Having read that MultiSystem is a no-charge option in 7.5 I would very much
like to test table partitioning and hopefully use it.
Rational:
We heavily use Multi-Member-transaction-Files, Physical & Logical (several
hundreds files)
Some such files have hundreds MBRs and a few over a thousand.
These files are managed by ADDPFM / ADDLFM / OVRDBF and such.
This is nice and dandy for day to day operations but makes for a difficult
task querying
and analyzing historical data.
So we regularly copy those files to a Single-MBR DataWarehouse-like files
adding the Member Name as a field (and a key) and use those DWH files for
historical analysis.

Several questions come to (my) mind when considering replacing it with
table partitioning:

1. How many partitions are allowed in a partitioned table or index?
2. After a partitioned table is created, can one use
ADDPFM/RMVM/CLRPFM/ADDLFM on it ?
(I've read that OVRDBF works with it)
3. Is there a performance penalty that comes with partitioned tables ?

All answers will be thankfully received.
Gad
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date: Sat, 17 Sep 2022 15:10:24 -0400
from: smith5646midrange@xxxxxxxxx
subject: RE: Table partitioning in 7.5

From everything that I have found (and I am still totally confused by

this),
table partitioning seems to be more about busting up the storage of a
single
member into multiple members based on a field in the table as opposed to
having multiple standalone members in a PF. This seem more like a bunch of
LFs with select clauses.

From the doc at https://www.ibm.com/docs/en/ssw_ibm_i_73/pdf/rzaf3pdf.pdf,

From page 1

There are two methods for partitioning data:
1. Partitioned tables - The data for a table is spread across multiple
members within a single physical file
on a single IBM i instance. This is the recommended method for physical
partitioning of data in a table.
2. Distributed files (distributed tables) - The data for a table is spread
across multiple IBM i instances.
This option is no longer recommended for use.

And from page 22

Or, to partition PAYROLL by range, use the following code:
CREATE TABLE PRODLIB.PAYROLL
(EMPNUM INT,
FIRSTNAME CHAR(15),
LASTNAME CHAR(15),
SALARY INT)
PARTITION BY RANGE(EMPNUM)
(STARTING FROM (MINVALUE) ENDING AT (500) INCLUSIVE,
STARTING FROM (501) ENDING AT (1000) INCLUSIVE,
STARTING FROM (1001) ENDING AT (MAXVALUE))

This statement results in a table that contains three partitions. The first
partition contains all rows where
EMPNUM is less than or equal to 500. The second partition contains all rows
where EMPNUM is between
501 and 1000 inclusive. The third partition contains all rows where EMPNUM
is greater than or equal to
1001.

Someone please correct me and include a link to some good IBM i
documentation on this.

-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Gad
Miron
Sent: Saturday, September 17, 2022 8:38 AM
To: midrange-l@xxxxxxxxxxxxxxxxxx
Subject: Table partitioning in 7.5

Hello sages

Having read that MultiSystem is a no-charge option in 7.5 I would very much
like to test table partitioning and hopefully use it.
Rational:
We heavily use Multi-Member-transaction-Files, Physical & Logical (several
hundreds files) Some such files have hundreds MBRs and a few over a
thousand.
These files are managed by ADDPFM / ADDLFM / OVRDBF and such.
This is nice and dandy for day to day operations but makes for a difficult
task querying and analyzing historical data.
So we regularly copy those files to a Single-MBR DataWarehouse-like files
adding the Member Name as a field (and a key) and use those DWH files for
historical analysis.

Several questions come to (my) mind when considering replacing it with
table
partitioning:

1. How many partitions are allowed in a partitioned table or index?
2. After a partitioned table is created, can one use
ADDPFM/RMVM/CLRPFM/ADDLFM on it ?
(I've read that OVRDBF works with it) 3. Is there a performance penalty
that comes with partitioned tables ?

All answers will be thankfully received.
Gad
--
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To post a message email: MIDRANGE-L@xxxxxxxxxxxxxxxxxx To subscribe,
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questions.

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link:
https://amazon.midrange.com



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