How to monitor slow queries

Hi,

We extensively use JIRA for bug tracking and over the couple of days we observed that our JIRA instance is acting slow in result of performance issues. we also see lot of JQUERY statements in atlassian-jira-slow-query.log. How one should analyze and determine these queries. An example of these are,


2011-05-18 02:24:54,943 http-4527-97 INFO jiraadmin 144x30201x57 2lu035 /rest/gadget/1.0/issueTable/jql [issue.search.providers.LuceneSearchProvider_SLOW] JQL query '{assignee = currentUser()} AND {resolution = "unresolved"} order by priority DESC, created ASC' produced lucene query '+issue_assignee:jiraadmin +resolution:-1' and took '420' ms to run.
2011-05-18 02:25:04,070 http-4527-26 INFO jiraadmin 144x30266x54 kbfirf /rest/gadget/1.0/issueTable/jql [issue.search.providers.LuceneSearchProvider_SLOW] JQL query '{assignee = currentUser()} AND {resolution = "unresolved"} order by priority DESC, created ASC' produced lucene query '+issue_assignee:jiraadmin +resolution:-1' and took '8695' ms to run.
2011-05-18 02:25:04,123 http-4527-90 INFO jiraadmin 144x30352x51 16zftld /rest/gadget/1.0/issueTable/jql [issue.search.providers.LuceneSearchProvider_SLOW] JQL query '{assignee = currentUser()} AND {resolution = "unresolved"} order by priority DESC, created ASC' produced lucene query '+issue_assignee:jiraadmin +resolution:-1' and took '8462' ms to run.
2011-05-18 02:35:45,680 http-4527-58 INFO jiraadmin 155x34925x39 1hcphy0 /secure/ComponentBoard.jspa [issue.search.providers.LuceneSearchProvider_SLOW] JQL query '{project = 10081} AND {component is EMPTY} AND {fixVersion is EMPTY} order by cf[10000] ASC, key ASC' produced lucene query '+projid:10081 +component:-1 +fixfor:-1' and took '429' ms to run.

Do we need to set up a monitoring from the backed (DB side) to see who's doing what? If it is ORACLE DB, how we can monitor that?

(If its with MySQL, just enabling slow query in my.cnf would be sufficient?.)
Please suggest

thanks