Checkpoint Buffers

checkpoint buffers buffers

The option buffers indicates how many buffers must be written to the temporary log file before performing a checkpoint that commits ongoing transactions to disk. If this limit is reached while transactions are in process, the checkpoint will happen only after all transactions have finished to guarantee atomic transactions.

The smaller the number of buffers, less efficient will be the overall performance of the system, but the databases involved will be more often updated.

If the number of buffers is big, ZIM Backup Server, if running, will take more time to perform the backup process.

Regardless of the number of buffers, in case of a disk crash, ZIM server will automatically recover all consistent transactions present in the temporary transaction file.

A checkpoint is triggered whenever the number of checkpoint transactions or the number of checkpoint buffers happens first.

The number of buffers should always be less than the half of the number of Maximum Data Blocks; if this happens, the number of buffers is adjusted accordingly.

Valid Settings

Range between 1 and 1000000.

Windows300
UNIX300

Object Sleep

object sleep milliseconds

The time milliseconds indicates how long Zim Server has to wait before attempting again to obtain control over some objects (locks, buffers, etc.) that are not available in memory.

This sleep time is some sort of “last chance” to acquire resources in memory before resorting to a pending list of objects where the object will wait longer.

Valid Settings

Range between 0 to 600.

Windows

10

UNIX

10

Secondary Lock Groups

secondary lock groups nn

 

This option indicates how many groups of secondary locks Zim Server has to maintain in memory in order to control and apply locks on ongoing transactions for locks that cannot be held in a quick way (see Quick Locks).

Valid Settings

A number from 10 to 100,000.

 

Windows7500
UNIX7500

 

Record Group Size

record group size nn

This is the size of a group of information related to blocks of data, like quick locks, locks, references to a block and users accessing blocks. Each file (that is, record group) can have this many record groups to speed up to relationship between real blocks of data in memory and real blocks of data on disk.

Valid Settings

A number from 16 to 256.

Windows

32

UNIX

32

Buffers Per User

buffers per user buffers

This option specifies the number of buffers to be allocated by each user to process data provided by Zim Server. The buffer allocation happens only in the client side and is independent of locks.

Valid Settings

Any directory path.

Windows

1000

UNIX

1000

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