IBM E16RMLL-I Implementation Guide - Page 531

Transactions

Page 531 highlights

the database using database unload and reload processing. By reloading the database, you compress and reorganize it. This process is described in detail in Chapter 14, "Advanced operations" on page 453. 15.3.2 Transactions This section covers server options that influence the performance and behavior of data movement within the server. TXNGROUPMAX The option TXNGROUPMAX specifies the number of files that are transferred as a group between a client and the server between transaction commit points. A group of client files is known as an aggregate or physical file. Client backup, archive, restore, and retrieve performance may improve by using a larger value for this option. TXNGROUPMAX is used in conjunction with the client TXNBYTELIMIT option. See "TXNBYTELIMIT" on page 506 for a more detailed description of the transaction process and the side effects on the recovery log. MOVEBATCHSIZE and MOVESIZETHRESH The MOVEBATCHSIZE and MOVESIZETHRESH options help tune the performance of the server processes that involve the movement of data between storage media. These processes include storage pool backup and restore, migration, reclamation, and move data. These options specify the number of files and the quantity of data that are to be moved and grouped together in a batch, within the same server transaction. MOVEBATCHSIZE and MOVESIZETHRESH apply to file aggregates, or physical files, as described under TXNGROUPMAX in the previous section. The number of client files moved for each server database transaction during a server storage pool backup or restore, migration, reclamation, or move data operation will be determined by the number and size of the files in the batch. If the number of files in the batch equals the MOVEBATCHSIZE before the cumulative size of the files becomes greater than the MOVESIZETHRESH, then the MOVEBATCHSIZE is used to determine the number of files moved or copied in the transaction. If the cumulative size of files being gathered for a move or copy operation exceeds the MOVEBATCHSIZE value before the number of files becomes equivalent to the MOVEBATCHSIZE, then the MOVESIZETHRESH value is used to determine the number of files moved or copied in the transaction. Chapter 15. Performance considerations 501

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Chapter 15. Performance considerations
501
the database using database unload and reload processing. By reloading the
database, you compress and reorganize it. This process is described in detail in
Chapter 14, “Advanced operations” on page 453.
15.3.2
Transactions
This section covers server options that influence the performance and behavior
of data movement within the server.
TXNGROUPMAX
The option TXNGROUPMAX specifies the number of files that are transferred as
a group between a client and the server between transaction commit points. A
group of client files is known as an
aggregate
or
physical file
. Client backup,
archive, restore, and retrieve performance may improve by using a larger value
for this option.
TXNGROUPMAX is used in conjunction with the client TXNBYTELIMIT option.
See “TXNBYTELIMIT” on page 506 for a more detailed description of the
transaction process and the side effects on the recovery log.
MOVEBATCHSIZE and MOVESIZETHRESH
The MOVEBATCHSIZE and MOVESIZETHRESH options help tune the
performance of the server processes that involve the movement of data between
storage media. These processes include storage pool backup and restore,
migration, reclamation, and move data.
These options specify the number of files and the quantity of data that are to be
moved and grouped together in a batch, within the same server transaction.
MOVEBATCHSIZE and MOVESIZETHRESH apply to file aggregates, or
physical files, as described under TXNGROUPMAX in the previous section.
The number of client files moved for each server database transaction during a
server storage pool backup or restore, migration, reclamation, or move data
operation will be determined by the number and size of the files in the batch. If
the number of files in the batch equals the MOVEBATCHSIZE before the
cumulative size of the files becomes greater than the MOVESIZETHRESH, then
the MOVEBATCHSIZE is used to determine the number of files moved or copied
in the transaction. If the cumulative size of files being gathered for a move or
copy operation exceeds the MOVEBATCHSIZE value before the number of files
becomes equivalent to the MOVEBATCHSIZE, then the MOVESIZETHRESH
value is used to determine the number of files moved or copied in the
transaction.