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Overview

In altibase_boot.log, a large number of messages with the title "reset Mutex Statistics" may be recorded. This document provides a brief description of this message.

 

 

Situation

The following message may be repeatedly recorded in altibase_boot.log.

Message format

--- reset Mutex Statistics ---
TRY_COUNT: 2102048999
LOCK_COUNT: 2147483647
MISS_COUNT: 59144056
------------------------------

 

Cause

This message is output when the values of the try_count, lock_count, and miss_count columns of the v$mutex performance view table exceed the maximum value and the values are initialized.This message appears when the values of the try_count, lock_count, and miss_count columns in the performance view table v$mutex exceed their maximum limit and are reset.

v$mutex records mutex-related information for concurrency control within the database. When the values of these columns continuously increase and exceed the maximum limit, a value overflow occurs. At that point, the values are logged in altibase_boot.log and then reset to zero.

Column description

Icon
  • try_count = number of mutex lock attempts
  • lock_count = number of successful mutex locks
  • miss_count = number of waits because the mutex lock was not held

 

6.3.1 or earlier

V$MUTEX table structure

iSQL> desc v$mutex;
[ ATTRIBUTE ]
-----------------------------------------------------
NAME TYPE
-----------------------------------------------------
NAME VARCHAR(64)
TRY_COUNT INTEGER // If the integer maximum value (2147483647) is exceeded, it will be logged.
LOCK_COUNT INTEGER
MISS_COUNT INTEGER
SPIN_VALUE INTEGER
TOTAL_LOCK_TIME_US BIGINT
MAX_LOCK_TIME_US BIGINT

 

6.5.1

V$MUTEX table structure
iSQL> desc v$mutex
[ ATTRIBUTE ]
------------------------------------------------------------------------------
NAME                                     TYPE
------------------------------------------------------------------------------
NAME                                     VARCHAR(64)
TRY_COUNT                                BIGINT        // When the BIGINT maximum value (9223372036854775807) is exceeded, the event is logged.
LOCK_COUNT                               BIGINT
MISS_COUNT                               BIGINT
SPIN_VALUE                               INTEGER
TOTAL_LOCK_TIME_US                       BIGINT
MAX_LOCK_TIME_US                         BIGINT

 

7.1 or later

V$MUTEX table structure
iSQL> desc v$mutex
[ ATTRIBUTE ]
------------------------------------------------------------------------------
NAME                                     TYPE
------------------------------------------------------------------------------
NAME                                     VARCHAR(64)
TRY_COUNT                                BIGINT        // When the BIGINT maximum value (9223372036854775807) is exceeded, the event is logged.
LOCK_COUNT                               BIGINT
MISS_COUNT                               BIGINT
SPIN_VALUE                               INTEGER
TOTAL_LOCK_TIME_US                       BIGINT
MAX_LOCK_TIME_US                         BIGINT
THREAD_ID                                VARCHAR(64)   // The ID of the thread that currently holds the lock

 

 

Solution

When the maximum number of columns that can store mutex-related information is reached, the information is recorded in altibase_boot.log, and there is no particular problem or action required.

 

 

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