Just for laughs: Mysql and Windows…

August 27th, 2009

Mysql for Windows?? Maybe.
Windows for Mysql?? NO WAY!
:-)

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A great talk

July 10th, 2009

John Allspaw and Paul Hammond (Flickr) talk about Dev and Ops Cooperation at Flickr (very good).

Have a look at Kitchen Soap blog.

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Oracle capacity planning with RRDTOOL

May 25th, 2009

RRDize everything, chapter 2

Oracle Database Server has the most powerful system catalog that allows to query almost any aspect inside an oracle instance.
You can query many v$ fixed views at regular intervals and populate many RRD files through rrdtool: space usage, wait events. system statistics and so on…

Since release 10.1 Oracle has introduced Automatic Workload Repository, a finer version of old good Statspack.
No matter if you are using AWR or statspack, you can rely on their views to collect data for your RRDs.

If you are administering a new instance and you haven’t collected its statistics so far, you can query (as example) the DBA_HIST_BG_EVENT_SUMMARY view to gather all AWR data about wait events. Historical views could be useful also to collect historical data once a week rather than query the fixed views every few minutes doing the hard work twice (you and AWR).

The whole process of gathering performance data and update rrd files can be resumed into the following steps:

- connect to the database
- query the AWR’s views
- build and execute an rrdtool update command
- check if rrd file exists or create it
- update the rrd file

The less rrdtool update commands you will execute, the better the whole process will perform.
Do it in a language you are comfortable with and that supports easily connection descriptors.

Since I’m very comfortable with php, I did it this way.

This is a very basilar script that works greatly for me with good performances:

#!/usr/bin/php -f
< ?php                                         
 
define('WD','/opt/oracle/awr');
$cs         = $_SERVER['argv'][1];
$user       = 'mymonitoruser';
$pass       = 'mystrongpassword'; 
 
/* open a new connection */
$ds = oci_connect($user, $pass, $cs)
        or die ("Cannot connect to Oracle Database ".$cs."\n");
 
/* setting client nls environment */
$sql = "alter session set nls_timestamp_format='MM/DD/YY HH24:MI'";
$stmt = oci_parse($ds, $sql);
oci_execute($stmt);
oci_free_statement($stmt);                                         
 
/* create directory that will contain rrds (if not exists) */
if(!file_exists(WD.'/'.$cs))
                mkdir(WD.'/'.$cs);
if(!file_exists(WD.'/'.$cs.'/wait'))
                mkdir(WD.'/'.$cs.'/wait');                   
 
/* function to create new RRDs */
function createRRD($name, $interval, $cs) {
        $hb = $interval*5; //heartbeat
        $cmd="rrdtool create ".WD."/".$cs."/wait/${name}.rrd -s ".$interval." \
                -b \"now -3month\" DS:waits:DERIVE:$hb:0:U \
                DS:mswaited:DERIVE:$hb:0:U \
                RRA:AVERAGE:0.5:1:1440 RRA:AVERAGE:0.5:30:336 \
                RRA:AVERAGE:0.5:120:372 RRA:AVERAGE:0.5:720:730 \
                RRA:MIN:0.5:1:1440 RRA:MIN:0.5:30:336 \
                RRA:MIN:0.5:120:372 RRA:MIN:0.5:720:730 \
                RRA:MAX:0.5:1:1440 RRA:MAX:0.5:30:336 \
                RRA:MAX:0.5:120:372 RRA:MAX:0.5:720:730 \
                RRA:LAST:0.5:1:1440";
        //print $cmd."\n";
        return passthru($cmd);
}                                                                              
 
/* take the snapshot frequency from dba_hist_wr_control
 to create the RDD with correct heartbeat value */
$sql = 'select extract(hour from snap_interval)*3600 +
extract(minute from snap_interval)*60 as SEED from DBA_HIST_WR_CONTROL';
$stmt = oci_parse($ds, $sql);
oci_execute($stmt);
$row = oci_fetch_assoc($stmt);
$interval = $row['SEED'];
unset($row);
oci_free_statement($stmt);                                              
 
/* statement definition that will collect
 all snapshots for a certain wait event with more than
 a certain amonut of time waited.
 Gathering ALL EVENTS could be time consuming and useless.
 I fetch rows ordered by event_name rather
 then by date because I can update many values
 into the same rrd with very few rrdupdate commands
*/
$sql = 'select s.END_INTERVAL_TIME END_INTERVAL_TIME,
    g.EVENT_NAME, g.WAIT_CLASS, g.TOTAL_WAITS,
    round(g.TIME_WAITED_MICRO/1000) MS
  from DBA_HIST_SNAPSHOT s,
   dba_hist_bg_event_summary g,
   v$instance i
 where s.SNAP_ID=g.SNAP_ID and g.wait_class!=\'Idle\'
  and g.TIME_WAITED_MICRO&gt;100000
  and s.instance_number=i.instance_number
  and s.instance_number=g.instance_number
 order by 2,1';                                      
 
/* default prefetch size (148) matches default snapshot retention (24hx7dd) */
$stmt = oci_parse($ds, $sql);
oci_set_prefetch($stmt, 148);
oci_execute($stmt);
 
$i=0;
$oldevent="";
while ($row = oci_fetch_assoc($stmt)) {
        if ($oldevent != $row['EVENT_NAME']) {
                //NEW EVENT DETECTED: WILL START A NEW UPDATE CMD
                if ($i != 0 &amp;&amp; !empty($cmd)) {
                        /* not the first occurrence,
                         I bet there's something in my buffer */
                        passthru($cmd);
                }
                $cleanName = preg_replace ("([^[:alnum:]_-])","_",$row['EVENT_NAME']);
                // if there is no rrd for this event, I create a new one
                if (!file_exists(WD."/".$cs."/wait/${cleanName}.rrd")) {
                        createRRD($cleanName, $interval, $cs);
                }
                /*
                * I initialize a new update command. This string act as a buffer: I append many
                * values to be updated so I'll update many values in a single command line:
                * less forks of rrdtool and less file opens: the whole update process has an
                * enormous improvement.
                */
                $precmd="rrdtool update ".WD."/".$cs."/wait/${cleanName}.rrd ";
                $lastcmd="rrdtool info ".WD."/".$cs."/wait/${cleanName}.rrd".
                        "| grep last_update | awk '{print \$NF}'";
                $last=trim(`$lastcmd`);
                printf ("%s - %s - last: %d\n", $row['EVENT_NAME'], $cleanName, $last);
                $i=0;
                $cmd=$precmd;
                $oldevent=$row['EVENT_NAME'];
        }
        $time=strtotime($row['END_INTERVAL_TIME']);
        //print "time: ".$time."  last: ".$last."\n";
        if ( $time &gt; $last ) {
                $cmd.=" ".$time.":".$row['TOTAL_WAITS'].":".$row['MS'];
                $i++;
        }
        if ($i &gt;= 40) {
                // when I reach 40 values per commandline I force
                // the update: next loop will reinitialize a new commandline.
                passthru($cmd);
                $cmd=$precmd;
                $i=0;
        }
        unset($row);
 
}
if ($i != 0) {
        /* one more update pending in my buffer */
        passthru($cmd);
}
oci_free_statement($stmt);
oci_close($ds);
?>

Depending on how many different wait events you have, you’ll have a certain number of rrd files:

# ls -l
total 3864
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 Streams_AQ__enqueue_blocked_on_low_memory.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 20 08:18 buffer_busy_waits.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 control_file_parallel_write.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 control_file_sequential_read.rrd
-rw-r--r-- 1 ludovico ludovico 165304 Apr 30 10:12 cursor__pin_S_wait_on_X.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 db_file_scattered_read.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 db_file_sequential_read.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 events_in_waitclass_Other.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 latch__cache_buffers_chains.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 latch__library_cache.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 11 13:22 latch__library_cache_lock.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 20 08:18 latch__redo_writing.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 latch__row_cache_objects.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 latch__shared_pool.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 library_cache_load_lock.rrd
-rw-r--r-- 1 ludovico ludovico 165304 Apr 15 13:17 library_cache_lock.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 log_buffer_space.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 log_file_parallel_write.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 log_file_sequential_read.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 log_file_single_write.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 log_file_switch_completion.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 11 13:22 log_file_sync.rrd
-rw-r--r-- 1 ludovico ludovico 165304 May 25 15:00 os_thread_startup.rrd

As you can see, they are not so big…

Once you have your data in rrd files, it’s quite simple to script even complex plots with several datasources. Everything depends on the results you want.
This script stack all my wait events for a certain instance: it takes the directory containing all the rrds as first argument and the number of hours we want to be plotted as second argument:

cs=$1
hours=${2:-148}
 
eventlist=`ls $cs/wait/*rrd`
 
colors[1]="#000000"
colors[2]="#000055"
colors[3]="#0000aa"
colors[4]="#0000ff"
colors[5]="#550055"
colors[6]="#aa00aa"
colors[7]="#ff00ff"
colors[8]="#550000"
colors[9]="#aa0000"
colors[10]="#ff0000"
colors[11]="#555500"
colors[12]="#aaaa00"
colors[13]="#ffff00"
colors[14]="#005500"
colors[15]="#00aa00"
colors[16]="#00ff00"
colors[17]="#005555"
colors[18]="#00aaaa"
colors[19]="#00ffff"
colors[20]="#555555"
colors[21]="#aaaaaa"
 
i=0
 
for event in $eventlist ; do
        if [ $i -eq 0 ] ; then
                end=`rrdtool info $event | grep last_update | awk '{print $NF}'`
                end=`rrdtool info $cs/wait/control_file_parallel_write.rrd | grep last_update | awk '{print $NF}'`
                cmd="rrdtool graph - -s end-${hours}hours -e $end  -v \"milliseconds waited\" -l 0 -w 640 -h 240 -t \"$cs WAIT PROFILE\""
                i=$(($i+1))
        fi
        color=${colors[$i]}
        echo $color
        evname=`basename $event | sed -e s/\.rrd\$//`
        cmd="$cmd  DEF:$evname=$event:mswaited:AVERAGE"
        cmd="$cmd  AREA:${evname}${color}:"$evname":STACK"
        i=$(($i+1))
        if [ $i -eq 20 ] ; then
                i=1
        fi
done
        cmd="$cmd  |display /dev/input"
        echo $cmd
        eval $cmd
exit

The resulting command is very long:

rrdtool graph - -s end-148hours -e 1243252800 \
 -v "milliseconds waited" -l 0 -w 640 -h 240 -t "mydb WAIT PROFILE"\
 DEF:Streams_AQ__enqueue_blocked_on_low_memory=mydb/wait/Streams_AQ__enqueue_blocked_on_low_memory.rrd:mswaited:AVERAGE \
 AREA:Streams_AQ__enqueue_blocked_on_low_memory#000000:Streams_AQ__enqueue_blocked_on_low_memory:STACK\
 DEF:buffer_busy_waits=mydb/wait/buffer_busy_waits.rrd:mswaited:AVERAGE \
 AREA:buffer_busy_waits#000055:buffer_busy_waits:STACK\
 DEF:control_file_parallel_write=mydb/wait/control_file_parallel_write.rrd:mswaited:AVERAGE \
 AREA:control_file_parallel_write#0000aa:control_file_parallel_write:STACK\
 DEF:control_file_sequential_read=mydb/wait/control_file_sequential_read.rrd:mswaited:AVERAGE \
 AREA:control_file_sequential_read#0000ff:control_file_sequential_read:STACK\
 DEF:cursor__pin_S_wait_on_X=mydb/wait/cursor__pin_S_wait_on_X.rrd:mswaited:AVERAGE \
 AREA:cursor__pin_S_wait_on_X#550055:cursor__pin_S_wait_on_X:STACK\
 DEF:db_file_scattered_read=mydb/wait/db_file_scattered_read.rrd:mswaited:AVERAGE \
 AREA:db_file_scattered_read#aa00aa:db_file_scattered_read:STACK\
 DEF:db_file_sequential_read=mydb/wait/db_file_sequential_read.rrd:mswaited:AVERAGE \
 AREA:db_file_sequential_read#ff00ff:db_file_sequential_read:STACK\
 DEF:events_in_waitclass_Other=mydb/wait/events_in_waitclass_Other.rrd:mswaited:AVERAGE \
 AREA:events_in_waitclass_Other#550000:events_in_waitclass_Other:STACK\
 DEF:latch__cache_buffers_chains=mydb/wait/latch__cache_buffers_chains.rrd:mswaited:AVERAGE \
 AREA:latch__cache_buffers_chains#aa0000:latch__cache_buffers_chains:STACK\
 DEF:latch__library_cache=mydb/wait/latch__library_cache.rrd:mswaited:AVERAGE \
 AREA:latch__library_cache#ff0000:latch__library_cache:STACK\
 DEF:latch__library_cache_lock=mydb/wait/latch__library_cache_lock.rrd:mswaited:AVERAGE \
 AREA:latch__library_cache_lock#555500:latch__library_cache_lock:STACK\
 DEF:latch__redo_writing=mydb/wait/latch__redo_writing.rrd:mswaited:AVERAGE \
 AREA:latch__redo_writing#aaaa00:latch__redo_writing:STACK\
 DEF:latch__row_cache_objects=mydb/wait/latch__row_cache_objects.rrd:mswaited:AVERAGE \
 AREA:latch__row_cache_objects#ffff00:latch__row_cache_objects:STACK\
 DEF:latch__shared_pool=mydb/wait/latch__shared_pool.rrd:mswaited:AVERAGE \
 AREA:latch__shared_pool#005500:latch__shared_pool:STACK\
 DEF:library_cache_load_lock=mydb/wait/library_cache_load_lock.rrd:mswaited:AVERAGE \
 AREA:library_cache_load_lock#00aa00:library_cache_load_lock:STACK\
 DEF:library_cache_lock=mydb/wait/library_cache_lock.rrd:mswaited:AVERAGE \
 AREA:library_cache_lock#00ff00:library_cache_lock:STACK\
 DEF:log_buffer_space=mydb/wait/log_buffer_space.rrd:mswaited:AVERAGE \
 AREA:log_buffer_space#005555:log_buffer_space:STACK\
 DEF:log_file_parallel_write=mydb/wait/log_file_parallel_write.rrd:mswaited:AVERAGE \
 AREA:log_file_parallel_write#00aaaa:log_file_parallel_write:STACK\
 DEF:log_file_sequential_read=mydb/wait/log_file_sequential_read.rrd:mswaited:AVERAGE \
 AREA:log_file_sequential_read#00ffff:log_file_sequential_read:STACK\
 DEF:log_file_single_write=mydb/wait/log_file_single_write.rrd:mswaited:AVERAGE \
 AREA:log_file_single_write#000000:log_file_single_write:STACK\
 DEF:log_file_switch_completion=mydb/wait/log_file_switch_completion.rrd:mswaited:AVERAGE \
 AREA:log_file_switch_completion#000055:log_file_switch_completion:STACK\
 DEF:log_file_sync=mydb/wait/log_file_sync.rrd:mswaited:AVERAGE \
 AREA:log_file_sync#0000aa:log_file_sync:STACK\
 DEF:os_thread_startup=mydb/wait/os_thread_startup.rrd:mswaited:AVERAGE \
 AREA:os_thread_startup#0000ff:os_thread_startup:STACK |display /dev/input

This is the resulting graph:
Graph plotted with rrdtool displaying Oracle instance Wait Events

OHHHHHHHHHHHH COOOOL!!!
;-)

Any comment is appreciated! thanks

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How to collect Oracle Application Server performance data with DMS and RRDtool

March 2nd, 2009

RRDize everything, chapter 1

If you are managing some Application Server deployments you should have wondered how to check and collect performance data.
As stated in documentation, you can gather performance metrics with the dmstool utility.
AFAIK, this can be done from 9.0.2 release upwards, but i’m concerned DMS will not work on Weblogic.

Mainly, you should have an external server that acts as collector (it could be a server in the Oracle AS farm as well): copy the dms.jar library from an Oracle AS installation to your collector and use it as you would use dmstool:

java -jar dms.jar [dmstool options]

There are three basilar methods to get data:

Get all metrics at once:

java -jar dms.jar -dump -a "youraddress://..." [format=xml]

Get only the interesting metrics:

java -jar dms.jar -a "youraddress://..." metric metric ...

Get metrics included into specific DMS tables:

java -jar dms.jar -a "youraddress://..." -table table table ...

What youraddress:// is, it depends on the component you are trying to connect:

opmn://asserver:6003
http://asserver:7200/dms0/Spy
ajp13://asserver:3301/dmsoc4j/Spy

If you are trying to connect to the OHS (Apache), be careful to allow remote access from the collector by editing the dms.conf file.

Now that you can query dms data, you should store it somewhere.
Personally, I did a first attempt with dmstool -dump format=xml. I wrote a parser in PHP with SimpleXML extension and I did a lot of inserts into a MySQL database. After a few months the whole data collected from tens of servers was too much to be mantained…
To avoid the maintenance of a DWH-grade database I investigated and found RRDTool. Now I’m asking how could I live without it!

I then wrote a parser in awk that parse the output of the dms.jar call and invoke an rrdtool update command.
I always use dms.jar -table command. The output has always the same format:

###SOF

Mon Mar 02 17:01:19 CET 2009

---------------
TABLE1_Name
---------------

record1_metric1.name:     value       units
record1_metric2.name:     value       units
....

record2_metric1.name:     value       units
record2_metric2.name:     value       units
....

---
TABLE2_Name
---

record1_metric1.name:     value       units
record1_metric2.name:     value       units
....

record2_metric1.name:     value       units
record2_metric2.name:     value       units
....

##EOF

So I written an awk file that works for me.
use it this way:

 java -jar dms.jar ... | awk -f parse_output.awk
####################
# parse_output.awk #
####################
 
#function pl() replaces all non alphanumeric occurrences with an underscore
function pl(input) {
        return gensub("[^[:alnum:]_-]","_","G",input);
}
 
# function get_rrd_path() returns a path where the rrd files should be placed
# I should rewrite a new path for each dms table... I'll skip many of them
function get_rrd_path() {
        if (table == "mod_oc4j_destination_metrics")
                return sprintf("%s/%s/%s/%s.rrd", record["Host"],
                    pl(table), pl(record["Name.value"]), pl(var) );
        if (table == "mod_oc4j_mount_pt_metrics")
                return sprintf("%s/%s/%s/%s/%s.rrd", record["Host"],
                    pl(table), pl(record["Destination.value"]), pl(record["Name.value"]), pl(var) );
        if (table == "ohs_server")
                return sprintf("%s/%s/%s.rrd", record["Host"], pl(table), pl(var) );
        if (table == "JVM")
                return sprintf("%s/%s/%s/%s.rrd", record["Host"],
                    pl(table), pl(record["Process"]), pl(var) );
        if (table == "opmn_process")
                return sprintf("%s/%s/%s/%s/%s/%s/%s/%s.rrd", record["Host"], pl(table),
                  pl(record["iasInstance.value"]), pl(record["opmn_ias_component"]),
                  pl(record["opmn_process_type"]),pl(record["opmn_process_set"]),
                  pl(record["Name"]), pl(var) );
 
        return sprintf("%s/%s/%s.rrd", record["Host"], pl(table), pl(var) );
}
# function process_record actually does the dirty work of invoking the update script
function process_record() {
        #every record has a timeStamp.ts metric that I should use to update my rrd
        ts=substr(record["timeStamp.ts"],0,10);
        for ( var in record ) {
        if ( var != "timeStamp.ts" &amp;&amp; record[var] ~ /^[[:digit:]]+$/ ) {
            if ( var ~ /\.(count|completed|time)$/ ) {
                dstype="DERIVE";
            } else {
                if ( var == "responseSize.value" ) {
                    dstype="DERIVE";
                } else {
                    dstype="GAUGE";
                }
            }
            rrdFile=sprintf("/path_to_data/%s",get_rrd_path());
            #### update_metric_rrd is a shell script listed below!!!!!
            cmd=sprintf("/path_to_scripts/update_metric_rrd %s %s %d %d",
                rrdFile,dstype,ts,record[var]);
            system(cmd);
            }
        }
}
 
# parse_record() populates an hash array
# with all metrics belonging to the table record
function parse_record() {
    #print "RRRR -  START OF RECORD (table " table ")"
    delete record
    while ( ! /^$/ ) {
        # I'm parsing the record as far I'm in this while statement
        # the array hash is the name of the dms metric basename.
        # $1 is the metric name but I have to trim the final ":"
        key=substr($1,0,length($1)-1)
        record[key]=$2
        getline
    }
    # this function is included in funcions.awk:
    # I invoke it to process the record I've just parsed
    process_record();
}
BEGIN {
    # as far as started is 0, I've never reached the first table
    started=0
}
 
#MAIN
{
    # I jump over the first lines until I reach the first table
    if (started==0) {
        while ( ! /^---/ ) {
           getline
        }
        started=1
    }
 
    # looking for the next occurrence of a table
    # all tables start with:
    # ----------
    # table_name
    # ----------
    if ( /^---/ ) {
        # first table reached: the next row is my table name,
        # then I reach again a dashed line -----
        getline table
        getline trash
        #print ""
        #print "##########################"
        print "  TABELLA " table
        #print "##########################"
        next
    }
 
    if ( ! /^$/ ) {
        # reached an empty line: could be the end of a record or the and of a table
        # since a new table is threated in previous "if" statement, I'm starting a new record.
        parse_record()
    }
 
}
 
END {
}

And this is the code for update_metric_rrd:

#!/bin/bash
RRDFILE=$1
DSTYPE=$2
TS=$3
VALUE=$4
 
rrdtool update $RRDFILE ${TS}:${VALUE}
 
if [ $? -ne 0 ] ; then
        DIR=`dirname $RRDFILE`
 
        [ -d $DIR ] || mkdir -p $DIR
        [ -f $RRDFILE ] || rrdtool create $RRDFILE -b "now-1month" -s 1800 \
                DS:metric:${DSTYPE}:7200:0:U \
                RRA:AVERAGE:0.5:1:672 \
                RRA:AVERAGE:0.5:4:1080 \
                RRA:AVERAGE:0.5:12:1460 \
                RRA:AVERAGE:0.5:48:1095 \
                RRA:MAX:0.5:4:1080 \
                RRA:MAX:0.5:12:1460 \
                RRA:MAX:0.5:48:1095 \
                RRA:LAST:0.5:1:672
        rrdtool update $RRDFILE ${TS}:${VALUE}
fi

Once you have all your rrd files populated, it’s easy to script automatic reporting. You would probably want a graph with the request count served by your Apache cluster, along with its linear regression:

rrdtool graph - -s "end-${hours}hours" -e $end \
                -v "Requests Completed/sec" \
        -w 640 -h 240 --slope-mode \
                -t "HTTP Requests for www.ludovicocaldara.net" \
                DEF:1request_completed=/data/wwwserver1/ohs_server/request_completed.rrd:metric:AVERAGE \
                DEF:2request_completed=/data/wwwserver2/ohs_server/request_completed.rrd:metric:AVERAGE \
                CDEF:request_completed=1request_completed,2request_completed,+ \
                VDEF:slope=request_completed,LSLSLOPE \
                VDEF:lslint=request_completed,LSLINT \
                CDEF:reg=request_completed,POP,slope,COUNT,*,lslint,+ \
                LINE1:reg#666666:"Regression" \
                AREA:1request_completed#4040AA:"wwwserver1"  \
                AREA:2request_completed#6666FF:"wwwserver1":STACK  \
        &gt; mygraph.png

This is the result:
OHS request completed
OHHHHHHHHHHHH!!!! COOL!!!!

That’s all for DMS capacity planning. Stay tuned, more about rrdtool is coming!

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More about Dataguard and how to check it

February 6th, 2009

After my post Quick Oracle Dataguard check script I have some considerations to add:
to check the gap of applied log stream by MRP0 process it’s sufficient to replace this query in the perl script I posted:

 SELECT SEQUENCE#, BLOCK# from v\$managed_standby
        WHERE process='RFS' AND client_process='LGWR'

with this new one:

 SELECT SEQUENCE#, BLOCK# from v\$managed_standby
        WHERE process='MRP0'

To check this you have to meet the following condition: You should have real-time apply enabled (and possibly NODELAY clause specified in your recover statement). Check it with this query:

SELECT RECOVERY_MODE FROM V$ARCHIVE_DEST_STATUS;

It should be “MANAGED REAL TIME APPLY”.
If not using realtime apply your MRP0 process will wait until you have a new archive, so even if you have redo transport mode set to LGWR you’ll wait for standby log completion. Your gap of applied redo stream will be at least one sequence#.

With transport mode set to LGWR and real-time apply the output of the perl script is similar to this one:

# ./checkDataGuard.sh
PROD   :       1230      20631
STANDBY:       1230      20613
18         blocks gap

The whole gap between your primary and standby database should be LOW.

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Interesting Slides about Capacity Planning

January 29th, 2009

Browsing the web I found this interesting presentation by John Allspaw:

Slides from ‘Capacity Planning for LAMP’ talk at MySQL Conf 2007.
(Damn, I had to clean out the embedded flash because of invalid markup…)

I’m preparing some stuff related to RRDTool, I’ll post soon here some code snippets.

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Awk snippet to count TCP sockets grouped by state

January 19th, 2009

Depending on the release of awk it could be:

#!/usr/bin/gawk -f
{
        if ( ($NF) in stats )  {
                stats[$NF] = stats[$NF]+1;
        } else {
                stats[$NF]=1;
        }
}
END {
        for ( var in stats) {
                print var " = " stats[var];
        }
}

I saved the script as netstat_c.
I have to filter my netstat output to match only my tcp sockets prior to pipe the output to the script.

On linux:

$ netstat -a | grep ^tcp | netstat_c
LISTEN = 13
ESTABLISHED = 74
TIME_WAIT = 7

This is great to check my webserver connections when I do stress tests.

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Clustering the RMAN catalog on a RAC environment

January 13th, 2009

You have your brand new RAC deployed on a cluster and you want to manage your backups through a recovery catalog.
Suppose you don’t have a dedicate server to host your catalog, perhaps you wouldn’t configure your catalog as a RAC database: so why don’t you use Clusterware to configure your catalog as a single instance in cold failover?

OTN has a very nice whitepaper describing how to protect a single instance database. This can be nicely applied on 10g, 10gR2 or 11g: Using Oracle Clusterware to Protect A Single Instance Oracle Database 11g.

Clusterware is appealing also for traditional cold failover clusters. Licensing allows you to use Clusterware as far as you protect Oracle software or 3rd party software that use Oracle as database backend.

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Quick Oracle Dataguard check script

January 5th, 2009

Oracle Dataguard has his own command-line dgmgrl to check the whole dataguard configuration status.
At least you should check that the show configuration command returns SUCCESS.

This is an hypothetic script:

#!/bin/bash
export ORACLE_HOME=/u1/app/oracle/product/10.2.0
export ORACLE_SID=orcldg
result=`echo "show configuration;" | \
  $ORACLE_HOME/bin/dgmgrl sys/strongpasswd | \
  grep -A 1 "Current status for" | grep -v "Current status for"`
if [ "$result" = "SUCCESS" ] ; then
    exit 0
else
    exit 1
fi

Another script should check for the gap between production online log and the log stream received by the standby database. This can be accomplished with v$managed_standby view.
The Total Block Gap between production and standby can be calculated this way:
Sum all blocks from v$archived_logs where seq# between Current Standby Seq# and Current Production Seq#. Then add current block# of the production LGWR process and subtract current block# from RFS standby process. This gives you total blocks even if there is a log sequence gap between sites.
This is NOT the gap of online log APPLIED to the standby database. THIS IS THE GAP OF ONLINE LOG TRANSMITTED TO THE STANDBY RFS PROCESS and can be used to monitor your dataguard transmission from production to disaster recovery environment.

This is an excerpt of such script (please take care that it does not check against RFS failures, so it can fails when RFS is not alive):

#!/u1/app/oracle/product/10.2.0/perl/bin/perl -w
use DBI;
use DBD::Oracle qw(:ora_session_modes);
# DB connection #
my $prod  = "orclprod";
my $stby = "orcldr";
my $prodh;
unless ($prodh = DBI->connect('dbi:Oracle:'.$prod,
  'sys', 'strongpassword',
  {PrintError=>0, AutoCommit => 0,
  ora_session_mode => ORA_SYSDBA}))  {
    print "Error connecting to DB: $DBI::errstr\n";
        exit(1);
}
$prodh->{RaiseError}=1;
 
my $stbyh;
unless ($stbyh = DBI->connect('dbi:Oracle:'.$stby,
  'sys', 'strongpassword',
  {PrintError=>0, AutoCommit => 0,
  ora_session_mode => ORA_SYSDBA}))  {
    print "Error connecting to DB: $DBI::errstr\n";
        $prodh->disconnect;
        exit(1);
}
$stbyh->{RaiseError}=1;
 
my $sth;
### query prod
$sth = $prodh->prepare( < <EOSQL );
        select SEQUENCE#, BLOCK# from v\$managed_standby
        where process='LGWR'
EOSQL
$sth->execute();
my ($psequence, $pblock) = $sth->fetchrow_array();
$sth->finish();
### query stdby
$sth = $stbyh->prepare( < <EOSQL );
        select SEQUENCE#, BLOCK# from v\$managed_standby
        where process='RFS' and client_process='LGWR'
EOSQL
$sth->execute();
my ($ssequence, $sblock) = $sth->fetchrow_array();
$sth->finish();
 
printf ("PROD   : %10d %10d\n", $psequence, $pblock);
printf ("STANDBY: %10d %10d\n", $ssequence, $sblock);
 
$sth = $stbyh->prepare( < <EOSQL );
        select nvl(sum(blocks),0)
        + $pblock - $sblock as BLOCK_GAP
    from v\$archived_log
        where sequence# between $ssequence and $psequence
EOSQL
$sth->execute();
my ($blockgap) = $sth->fetchrow_array();
$sth->finish();
printf ("%-10d blocks gap\n", $blockgap);
 
$stbyh->disconnect;
$prodh->disconnect;

Any comment is appreciated!

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Tips: Bash Prompt and Oracle

December 30th, 2008
export PS1=\u@\h:\w\$

I disagree with default bash prompt. Do you? It’s quote common to work with long paths:

ludovico@host:/u01/app/oracle/product/10.2.0/network/admin$ \
/nooo/this/command/line/is/really/long/and/offcourse -I \
-will -wrap -my -command -line

and, when working on multi-database environments I need to check my environment:

env | grep -i oracle
#or
echo $ORACLE_SID
echo $ORACLE_HOME

I currently use this prompt, instead:

export PS1=$'\\n# [ $LOGNAME@\h:$PWD [\\t] [`ohvers` SID:${ORACLE_SID:-"no sid"}] ]\\n# '
 
# [ ludovico@caldara_2k:/u01/app/oracle/product/10.2.0/db_1/network/admin [23:15:58] [10.2.0 SID:orcl] ]
#

What is `ohvers`?? I defined this function to get the version of oracle from my ORACLE_HOME variable:

ohvers ()
{
echo -n $ORACLE_HOME | sed -n 's/.*\/\([[:digit:].]\+\)\/.*/\1/p'
}

Pros:

  • I have a blank line that separate my prompt from previous output
  • I get the system clock (useful when saving my konsole history. Did I say konsole?)
  • I can see my Oracle Environment before launching dangerous commands
  • I have an empty line to start my endless commands
  • I have a lot of sharps “#” : they are fine against wrong copy&paste operations…

Suggestions?

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