users can not add comments on the page

Cause
org.springframework.dao.DataIntegrityViolationException: Hibernate operation: could not insert: com.atlassian.confluence.pages.Comment#7832303; SQL []; Duplicate entry '7832303' for key 'PRIMARY'; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '7832303' for key 'PRIMARY'
at org.springframework.jdbc.support.SQLStateSQLExceptionTranslator.translate(SQLStateSQLExceptionTranslator.java:110)

caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '7832303' for key 'PRIMARY'
at sun.reflect.GeneratedConstructorAccessor709.newInstance(Unknown Source)

Stack Trace:[hide]

org.springframework.dao.DataIntegrityViolationException: Hibernate operation: could not insert: com.atlassian.confluence.pages.Comment#7832303; SQL []; Duplicate entry '7832303' for key 'PRIMARY'; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '7832303' for key 'PRIMARY'
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '7832303' for key 'PRIMARY'
at sun.reflect.GeneratedConstructorAccessor709.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1038)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3563)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3495)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2113)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2693)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2102)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2395)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2313)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2298)