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Database Administrator's Guide

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Transaction Processing Keywords

Full ACID transaction processing of data is the gold standard for ensuring data integrity. Maintaining database changes in write-ahead logs to secure data is a complex and intricate process. As such, multiple features and options are available to fine tune this process for the best performance vs. integrity.

 
AUTO_PREIMG

Allows newly created non-transaction files to be created in PREIMG mode.

 
AUTO_TRNLOG

Extends the automatic transaction support to include recoverable transactions without any application change.

 
AUTO_TRNLOG_LIGHT

Automatic transactions will be considered “light weight” so the transaction log is not flushed to disk on an automatic commit.

 
AUTOTRAN_ON_CREATE

A transaction will automatically be started when creating a transaction-controlled ISAM file.

 
CHECKPOINT_FLUSH

Sets the maximum number of checkpoints to be written before a buffer (data or index) holding an image for a transaction controlled file will be flushed.

 
CHECKPOINT_IDLE

Specifies the time in seconds between checkpoint checks.

 
CHECKPOINT_INTERVAL

Sets the interval between checkpoints (which can speed up recovery at the expense of performance during updates).

 
CHECKPOINT_PREVIOUS

If the checkpoint used for automatic recovery does not appear to be valid, enables the server to attempt to start recovery at the location of the next to last checkpoint.

 
CHKPDFC_LOG_LIMIT

Specifies how many consecutive logs may be processed without a checkpoint until the FairCom DB Server terminates.

 
COMMIT_DELAY

Controls the time, in milliseconds, the transaction manager waits after a transaction completes before flushing the transaction to disk.

 
COMMIT_DELAY_BASE

Determines the rate at which the nominal commit delay time is adjusted as the number of cohorts increases or decreases.

 
COMMIT_DELAY_MINIMUM

Minimum time allowable for commit delay to be overridden - Do not use unless instructed to by FairCom.

 
COMMIT_DELAY_SCALE

For advanced control of the intricate commit delay timing statistics by adjusting the commit delay time calculation.

 
COMMIT_DELAY_USEC

Same as COMMIT_DELAY, but interpreted as microseconds.

 
COMMIT_LOCK_DEFER_MS

Provides an additional tuning mechanism for the COMMIT_READ_LOCK retry value.

 
COMPATIBILITY LOG_WRITETHRU

Instructs the FairCom DB Server to open its transaction logs in synchronous write mode.

 
COMPATIBILITY TDATA_WRITETHRU

Forces transaction controlled data files to be written directly to disk, skipping the calls to flush their OS buffers.

 
COMPATIBILITY TINDEX_WRITETHRU

Forces transaction controlled index files to be written directly to disk, skipping the calls to flush their OS buffers.

 
FIXED_LOG_SIZE

Disables the FairCom DB Server from automatically adjusting the size of transaction log files to accommodate long records.

 
FORCE_LOGIDX

Allows LOGIDX index file mode support to be forced on, off, or disabled.

 
KEEP_LOGS

Specifies the number of non-active transaction log files kept on disk in addition to the active log files.

 
KEEP_RESTORE_POINTS

Allows the server to maintain information about the last N Restore Points.

 
LOG_COMPRESSION_FACTOR

Affects how compression is applied to log entries: if the compression does not fit in a buffer of size (<factor> * input_size / 100), then no compression takes place. Not currently supported.

 
LOG_COMPRESSION_THRESHOLD

Affects how compression is applied to log entries: if the variable region is less than this threshold, no compression is attempted. Not currently supported.

 
LOG_EVEN

The alternative name for even numbered transaction log files.

 
LOG_ODD

The alternative name for odd numbered transaction log files.

 
LOG_PAGE_SIZE

Changes the page size block of the transaction log buffer.

 
LOG_SPACE

Specifies the number of megabytes of disk space allocated to storing active transaction logs.

 
LOG_TEMPLATE

Enables transaction log templates.

 
LOG_TEMPLATE_COPY_SLEEP_PCT

Specifies the percentage of data that is written to the target transaction log file after which the copy operation sleeps for the number of milliseconds specified for the LOG_TEMPLATE_COPY_SLEEP_TIME option.

 
LOG_TEMPLATE_COPY_SLEEP_TIME

Causes the copying of the log template to pause for the specified number of milliseconds each time it has written the percentage of data specified by LOG_TEMPLATE_COPY_SLEEP_PCT to the target transaction log file.

 
LONG_TRANSACTION_MS

Any transaction that exceeds the elapsed transaction time specified will be considered a long transaction for monitoring purposes.

 
MAX_USER_LOG_ENTRY_BYTES

Specifies an optional limit for how many active transaction logs a transaction spans before it is aborted or abandoned.

 
MAX_USER_LOGS

Controls how many logs a transaction can span before attempts are made to abort or abandon the transaction.

 
PREIMAGE_FILE

The alternative name for the file containing preimages swapped to disk.

 
START_EVEN

The alternative name for even numbered start file.

 
START_ODD

The alternative name for odd numbered start file.

 
SUPPRESS_LOG_FLUSH

Causes transaction begin and commit operations to skip the flushing of the log file when its argument is YES.

 
SUPPRESS_LOG_SYNC

Skips the sync'ing to disk from a log flush operation.

 
TRAN_HIGH_MARK

Specifies a transaction number threshold value.

 
TRAN_OVERFLOW_THRESHOLD

Allows the server administrator to determine when the server will issue a warning that its transaction number is approaching the limit.

 
TRAN_TIMEOUT

Sets a time limit on a transaction after which the transaction is aborted.

 
TRANSACTION_FLUSH

Controls the maximum number of updates to a buffer (data or index) before it is flushed.

 
UNBUFFERED_LOG_IO

Enables separate unbuffered I/O for transaction logs.

In This Section

AUTO_PREIMG

AUTO_TRNLOG

AUTO_TRNLOG_LIGHT

AUTOTRAN_ON_CREATE

CHECKPOINT_FLUSH

CHECKPOINT_IDLE

CHECKPOINT_INTERVAL

CHECKPOINT_PREVIOUS

CHKPDFC_LOG_LIMIT

CLEANUP_ABLIST_ON_ABORT

COMMIT_DELAY

COMMIT_DELAY_BASE

COMMIT_DELAY_MINIMUM

COMMIT_DELAY_SCALE

COMMIT_DELAY_USEC

COMMIT_LOCK_DEFER_MS

COMPATIBILITY LOG_WRITETHRU

COMPATIBILITY TDATA_WRITETHRU

COMPATIBILITY TINDEX_WRITETHRU

COMPATIBILITY LOCK_EXCL_TRAN

DELAYED_DURABILITY

DELSTK_COMMIT_SEC

FIXED_LOG_SIZE

FORCE_LOGIDX

KEEP_LOGS

KEEP_RESTORE_POINTS

LEAF_NODE_READ_LOCK

LOG_COMPRESSION_FACTOR

LOG_COMPRESSION_THRESHOLD

LOG_EVEN

LOG_ODD

LOG_PAGE_SIZE

LOG_SPACE

LOG_TEMPLATE

LOG_TEMPLATE_COPY_SLEEP_PCT

LOG_TEMPLATE_COPY_SLEEP_TIME

LONG_TRANSACTION_MS

MAX_PREIMAGE_DATA

MAX_PREIMAGE_SWAP

MAX_USER_LOG_ENTRY_BYTES

MAX_USER_LOGS

PREIMAGE_FILE

START_EVEN

START_ODD

SUPPRESS_LOG_FLUSH

SUPPRESS_LOG_SYNC

TRAN_HIGH_MARK

TRAN_OVERFLOW_THRESHOLD

TRAN_TIMEOUT

TRANSACTION_FLUSH

UNBUFFERED_LOG_IO

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