select sqx_estcost,                        sqx_sqlstatement                        from syssqexplain                        order by sqx_estcost desc                        

onstat –g act                        Threads:                        tid tcb rstcb prty status vp-class name                        141904 84176538 8030eab8 2 running 1cpu sqlexec                        onstat –u | grep 8030eab8                        Userthreads                        address flags sessid user tty wait tout locks nreads nwrites                        8030eab8 Y--P--- 131047 informix - 84022480 0 1 11671 14722                        onstat –g sql 131047                        Sess SQL Current Iso Lock SQL ISAM F.E.                        Id Stmt type Database Lvl Mode ERR ERR Vers                        131047 DELETE (all) testdb DR Wait 10 0 0 9.03                        Current SQL statement :                        delete from my_tab                        Last parsed SQL statement :                        delete from my_tab                        

  cat <<! > check.sql                        -- 系統順序掃描較多時(shí)，被多次順序掃描的大表，如果有，應該考慮增加索引                        select first 5 substr(t.tabname,0,20) tabname,substr(dbsname,0,10) dbname,                        nrows*rowsize*p.seqscans costs,                        substr(p.seqscans,0,8) seqscans,substr(nrows,0,8) nrows                        from sysmaster:sysptprof p , systables t,sysmaster:sysprofile s                        where p.tabname = t.tabname                        and p.seqscans > s.value/50                        and s.name = 'seqscans'                        --and s.value > 2000000                        and nrows > 2000                        order by 3 desc                        !                        dbaccess sysmaster <<!                        unload to /tmp/db delimiter ';'                        select 'dbaccess '||trim(name)||' check.sql' from sysdatabases                        where name not like 'sys%'                        !                        ksh /tmp/db