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Connection Failure
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There may be a case when the DB cannot be accessed while the server or Altibase process is running normally. There can be five types of situations like this:
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Type | Checklist
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User account restrictions | The user account restrictions can be resolved by checking the result of limit -n, increasing this value, and restarting Altibase. Generally, it is recommended to set the file descriptor value to unlimited, and it should be set to at least 4096.
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Error in conenction connection attempt | If there is an error in the connection attempt, the configuration part must be checked in which the connection is attempted. Check whether the entered use account and password or the IP address to connect is are entered incorrectly, and whether a value different from PORT_NO set in $ALTIBASE/conf/altibase.properties is not attempted.
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Network failure | It is necessary to first check whether pack errors occur with netstat, and to check whether normal ftp/telnet connection from other devices to the drive where Altibase is installed is possible, and that there is no significant performance degradation in packet transmission and reception.
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Insufficient disk space | Check the disk usage by using a command such as df (bdf), and then replenish insufficient disk space. |
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Resources include all of the logical space used by Altibase form from physical memory/disk space. This section describes how to respond to each situation that may occur during the operation.
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Type | Method | ||||||||||||||
Insufficient user memory tablespace | ALTER TABLESPACE
ALTER AUTOEXTEND OFF;ALTER TABLESPACE [tablespace name] ALTER AUTOEXTEND ON MAXSIZE 1G
Execute the above commands in order. | ||||||||||||||
Insufficient SYS_TBS_MEM_DATA/SYS_TBS_MEM_DIC tablespace or If it cannot be resolved with the ALTER TABLESPACE command. | If the above error occurs in the SYS_TBS_MEM_DATA/SYS_TBS_MEM_DIC tablespace, it annot cannot be solved with the above method.
DELETE FROM
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Insufficient disk tablespace | ALTER TABLESPACE
ADD DATAFILE
Since the tablespace name is specified when an error message displays earlier, specify the tablespace name. |
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In case of insufficient memory, there is no separate countermeasure during the service. However, it is recommended to periodically collect the following results because the current status must be acquired.
SET LINESIZE 1000SELECT *FROM V$MEMSTATORDER BY
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The above query shows the current usage status of memory resources inside Altibase. With this information, it is possible to compare and analyze which module has a large memory increase with a periodic result log. (Comparison of results of the previous day/same day)
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Altibase supports MVCC. MVCC is a technique that can improve the performance of DBMS itself by preventing waiting between inquiry/change transactions. (For more detailed information, please refer to the "Altibase MVCC & GC Guide".) According to the implementation of MVCC, there are data to be deleted called Garage Data. If there is a large amount of data to be deleted or queries with a long-running time, the data to be deleted cannot be deleted until the corresponding transaction is completed. As a result, an increase in online log files or an increase in physical memory may occur. Queries with a long-running time that cause this phenomenon can be checked as follows.
AND
This query retrieves queries that are currently being executed and execution time is more than 100 seconds.
SELECT
ID,
ID FROM V$TRANSACTION WHERE
MINMEMSCNINTXS FROM V$MEMGC LIMIT 1))
This query retrieves queries that have been executing for a long time to prevent the processing of the data to be deleted. |
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If the above error types occur as a cause in the Altibase trace log, there are cases where the system error code is also recorded when an error message is recorded. It is also possible to check whether insufficient system resources occurs occur with the corresponding system error code.
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Replication Failure
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Altibase provides a data replication method using TCP/IP network for high availability. If there is any delay or other error during the service with replication, take the following actions.
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Type | Method | ||||||||
Existence of Sender | SELECT
If the Sender is running normally, the result of the above query should be displayed as "1" or higher. | ||||||||
Existence of Receiver | SELECT
If the Receiver is running normally, the result of the above query should be displayed as "1" or higher. (Must exist as many as the number of redundant objects) |
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The problem that will be caused in the replication Sender/Receiver is that the data to be sent with replication cannot be sent, and data is changed. Therefore, it is necessary to monitor the status of the replication Sender, which is called the replication gap.
SELECT
; REP_NAME REP_GAP
REP1 0
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REP_NAME refers to the object name of the replication, and the size from the log record currently being sent by REP_GAP to the last log record that has not been sent yet (default in MB).
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