[pgsql-jp: 36719] process exited abnormally and possibly corrupted shared memory.が発生する

[fukuda]

福田と申します。

Linux: 2.4.18-bf2.4
Postgresql: 7.4.9

にて運用中のサービスにおいてDB接続ができたり
できなくなったりする状態になりました。
postgresql.logには以下のメッセージが出力されており、
プロセスの終了と生成を繰り返しているようなのです。

Feb 18 04:18:01 **** postgres[3023]: [152-3]  process exited abnormally and possibly corrupted shared memory.
Feb 18 04:18:01 **** postgres[3013]: [149-3]  process exited abnormally and possibly corrupted shared memory.
Feb 18 04:18:01 **** postgres[3004]: [149-3]  process exited abnormally and possibly corrupted shared memory.
Feb 18 04:18:01 **** postgres[3001]: [149-3]  process exited abnormally and possibly corrupted shared memory.
Feb 18 04:18:01 **** postgres[2994]: [152-3]  process exited abnormally and possibly corrupted shared memory.
Feb 18 04:18:01 **** postgres[2987]: [149-3]  process exited abnormally and possibly corrupted shared memory.
Feb 18 04:18:01 **** postgres[3113]: [152-4] HINT:  In a moment you should be able to reconnect to the database and repeat your command.
Feb 18 04:18:01 **** postgres[3141]: [150-3]  process exited abnormally and possibly corrupted shared memory.
Feb 18 04:18:01 **** postgres[3106]: [149-4] HINT:  In a moment you should be able to reconnect to the database and repeat your command.
Feb 18 04:18:01 **** postgres[3087]: [152-4] HINT:  In a moment you should be able to reconnect to the database and repeat your command.
Feb 18 04:18:01 **** postgres[3080]: [149-4] HINT:  In a moment you should be able to reconnect to the database and repeat your command.
(同じメッセージなので省略)
Feb 18 04:18:01 **** postgres[2987]: [149-4] HINT:  In a moment you should be able to reconnect to the database and repeat your command.
Feb 18 04:18:01 **** postgres[3141]: [150-4] HINT:  In a moment you should be able to reconnect to the database and repeat your command.
Feb 18 04:18:01 **** postgres[28538]: [151-1] LOG:  all server processes terminated; reinitializing
Feb 18 04:18:01 **** postgres[3142]: [152-1] LOG:  database system was interrupted at 2006-02-18 04:17:31 JST
Feb 18 04:18:01 **** postgres[3142]: [153-1] LOG:  checkpoint record is at B/231D70A0
Feb 18 04:18:01 **** postgres[3142]: [154-1] LOG:  redo record is at B/231D70A0; undo record is at 0/0; shutdown TRUE
Feb 18 04:18:01 **** postgres[3142]: [155-1] LOG:  next transaction ID: 151535051; next OID: 3385122
Feb 18 04:18:01 **** postgres[3142]: [156-1] LOG:  database system was not properly shut down; automatic recovery in progress
Feb 18 04:18:01 **** postgres[3142]: [157-1] LOG:  redo starts at B/231D70E0
Feb 18 04:18:01 **** postgres[3142]: [158-1] LOG:  record with zero length at B/23202448
Feb 18 04:18:01 **** postgres[3142]: [159-1] LOG:  redo done at B/23202424
Feb 18 04:18:02 **** postgres[3145]: [152-1] FATAL:  the database system is starting up
Feb 18 04:18:04 **** postgres[3142]: [160-1] LOG:  database system is ready

postgresqlを再起動しても効果なく、
googleなどで検索しても、有益な情報が見付けることができませんでした。
どなたか、この状況を改善する方法をご存じないでしょうか
よろしくお願いいたします。