Mike Ault's thoughts on various topics, Oracle related and not. Note: I reserve the right to delete comments that are not contributing to the overall theme of the BLOG or are insulting or demeaning to anyone. The posts on this blog are provided “as is” with no warranties and confer no rights. The opinions expressed on this site are mine and mine alone, and do not necessarily represent those of my employer.

Monday, March 26, 2012

A Tragedy Unfolds

Trayvon Martin was killed by a gunshot from George Zimmerman's handgun. This is an undisputed fact. However, what led up to George feeling he had to shoot Trayvon is what is in doubt.

From what we can piece together Zimmerman is a self appointed neighborhood watch that has made over 40 calls to 911 over the last year. Zimmerman has made so many calls he is almost considered a nuisance to the local police. Needless to say this shows a certain zeal for being a neighbor hood watch almost bordering on obsession. Zimmerman reportedly desired to be a policeman according to some reports.

Trayvon Martin (despite the cute 14 year old he is pictured in the press) was 17 years old and black. He was wearing a gang related item of clothing, a hoodie. Now, I have worn hoodies and I am sure many of you have, there is nothing inherently damning by wearing a hoodie. However, would I wear a known gang related item in an area where it might be misconstrued? Probably not. Anyway, Trayvon, according to testimony, had left his fathers house and was walking to a local convenience store to get a few harmless items (tea and candy of some sort)when the shooting occurred.

From what has been pieced together Zimmerman spotted what he considered to be a suspicious person in an area where crime was on the uptick, someone he didn't recognize as a part of the neighborhood. He called 911 and started to follow Martin in his vehicle. Martin, noticing he was being followed pulled his hood up and started moving faster. At this point Zimmerman was told by the 911 operator not to pursue him. He did anyway, after losing him, he parked his vehicle and looked around on foot. What happens next is still not clear.

Zimmerman apparently pursued for a while, then started back to his truck, at which point he was supposedly attacked by Martin from the left rear. Now, does the act of stopping the pursuit then put Zimmerman back under the protection of the Castle law?

Castle law where Zimmerman resides states that when attacked you have no duty to retreat, that you may defend yourself up to and including lethal force from a concealed weapon. Zimmerman had a concealed weapons permit and carried a pistol.

An eyewitness has stated he saw Trayvon on top of Zimmerman, hitting him in the face and pounding his head into the concrete, pleas for help, identified as either coming from Zimmerman or Trayvon are recorded on 911 tapes. The witness went to a different window to get a better view, when he looked back out, he saw Trayvon laying on the ground and Zimmerman by him with the gun. The police showed up 2 minutes later. Zimmerman was bleeding from his nose and the back of head and the back of his clothes were wet from the grass.

So, what happened? Who knows, what you feel happened will be colored by your viewpoint. Both Zimmerman, and I am sure Trayvon, felt justified in whatever they did. Was Castle law to blame? I assume the detractors would have us all run from any confrontation, giving over anything asked us up to and including our money, health and even life before hurting someone else. However, places where you are required to flee until your back is to the wall and only then can you defend yourself, have a terrible record of fatalities. Those places that have a requirement to flee also have strict gun laws thus insuring an unarmed populace not able to defend themselves.

Zimmerman should have stopped following Trayvon as soon as the 911 operator told him to. Since Trayvon was not presenting a threat Zimmerman should have reported him, then gone on about his business. So in pursuing Trayvon, had Trayvon attacked him, Trayvon would be in the right in accordance with the Castle law as Zimmerman had become the aggressor. However, if it happened as Zimmerman has said, and, the physical evidence as presented thus far seems to support, that while he had been pursuing Treyvon, he lost sight of him and was returning to his truck, thus, no longer the aggressor, when he was attacked by Trayvon, then the Castle law comes back to being on Zimmerman's side. If Zimmerman felt that he had no other recourse, then using his concealed weapon was his right under the law.

At 6 foot and 160 pounds to 5'9" (no weight given) Trayvon had reach and possibly strength on his side. At 17 I was only 150 pounds at 5'10" and I could press 200 pounds, run 5 miles, swim a mile and was pretty fast with my hands. If I had attacked an older, out of shape man, I feel I could have won the day. The picture shown of Trayvon is not of a 6 foot 160 pound teenager, it is apparently of a 14 year old that looks maybe 5' 6" and a little over 100 pounds if that. Let's see a current High school picture. Oh, right, that wouldn't garner the same amount of sympathy.

It will be interesting to see how this tragedy unfolds, I would not want to be on the jury if it comes to that. My prayers go out to Trayvon's and George's families as both will suffer from the consequences of this for years to come.

Tuesday, March 20, 2012

Spring is in the air

Spring is in the air, literally here in Atlanta. Our pollen count is at 9000+ and rising and a yellow haze envelopes everything turning all cars into yellow taxi wantabes. With the warmer weather my thoughts turn toward scuba diving. Of course that means I need to get the regulators in for servicing at $90 a pop, see what tanks need to be inspected and which ones hydroed. I guess there is a cost for everything.

I also think about fishing. Standing hip deep in rushing cold water, flipping the fly out into just the right spot and feeling that sudden tug that shows the trout (or any other fish) has taken the challenge and wants to play. Hmmm...fresh caught trout fried with a little butter, dill and lemon juice.

Of course the barbecue season is already in full swing, had friends over already for hamburgers and hotdogs. Cooked some great pork chops the other day and some barbecue chicken. Maybe this weekend I'll pull out the last venison roast and rubbed with olive oil, seasoned with sage and garlic and wrapped in bacon, cook it over a slow fire until it is falling apart...

Also time to start planting the garden. Tomatoes, peppers, maybe some snow peas (if I can keep the neighborhood deer away) also spinach, maybe strawberries...

Well, time is flying by, so must close for now, spring is calling!

Wednesday, March 14, 2012

Working Hard on New Novel

Well, I have 122 manuscript pages single spaced so far, that is about 220 book pages. I seem to be adding about 5-10 pages a week. Things are reaching the climax as the several threads of the story come together. I plan on submitting this one to a small press my good friend and fellow author (Bottom Dwellers) Shane Etter uses. Shane's next book, titled "Forest Dwellers" is going in to the editor shortly and should be available soon.

My new novel will be entitled "Prelude to Darkness" and details the effects of an EMP on the main character, his wife, their neighbors and of course the antagonist...each is a separate story line woven together to reach a climax that should be great I hope!

If you haven't seen my other attempts at novels they are shown on Scubamage and can be purchased there if you are so inclined! Well, enough catching up, I have some writing to do!

Sunday, March 04, 2012

Pondering on a Saturday Morning

I have been keeping up with old interests lately. Reading about the space program (or lack thereof) and potential consequences of continued space exploration and exploitation. Of course I chose the words consequences and exploitation deliberately, as did the writers of the articles I read, as they have a negative connotation to most people. I chose them to demonstrate deliberate slanting, they chose them to do deliberate slanting of their message. They took articles which could have been encouraging and uplifting and made them deliberately negative by simple word usage, essentially damning them by faint praise.

In one article they worried over what would happen should we mine the moon for He3 (supposedly needed for fusion) and pondered our damaging the eco-system of the moon (please, stop laughing, they were serious!) They also questioned whether we should seek to do even limited terra-forming of the moon or Mars, again sighting fears over damaging geologic or microscopic eco-systems. I guess it is better to leave all our eggs in one basket (Earth) and just hope our good intentions will prevent a super-flare or stray asteroid from ending us.

Another article fussed about “What will future generations due if we use up the fossil fools or natural gas?” well, they will do what future generations have always done, find something better! I have always contended that fossil fuels, natural gas and nuclear fission are bridge technologies to get us to future technologies. Whether those future technologies will be based in fusion (cold or hot) or in zero-point energy or in some heretofore unknown technology I don’t know, but future generations will!

The big problem with many people in the media industry is they can’t see past their limited technological education. With science and technology taking such a low rung on the education ladder these days (after all, it makes little Johnnie feel bad to not be smart enough to understand it, so we will skip it) it is no wonder journalists feel so threatened by it. We are all limited by our horizons. The closer and safer we make those horizons the more limited is our world view and the fewer options we have. Many people need a good dose of science fiction! We used to base our future on doing the impossible, climbing the unclimbed mountain, going where no one has gone before, now we don’t even have a space program to speak of unless we go begging off the Russians (President Kennedy is spinning in his grave while Nixon is dancing a jig in whatever of the nine-hells he is in.)

Unless we rekindle the imaginations and invest in the future of our children by doing so, we are in for a rough ride. I fear we may be on the slide down into obscurity here in the USA. Unless we can revitalize speculative thinking we are doomed.

Friday, March 02, 2012

Using Flash Cache

In this final test series we will compare the best result from the memory only, Keep and Recycle and first rows tests with the best result with a flash cache set. Tests were completed comparing using a slightly faster server mounted PCIe flash cache to a flash based san so the results will not be as dramatic as when testing server mounted PCIe flash cache against disk based storage.

The flash cache was sized at the suggested 2X the database cache size (90 gb) and then a run with the flash cache set to zero was run. Note that for the first run appropriate tables and indexes were assigned to be kept in the flash cache, other tables where set to default. Figure 1 shows the results from use of the Smart Flash Cache with Flash as storage.

Figure 1: TPS verses GB in the Flash cache

At least for our testing with the database on a RamSan630 SSD and the flash cache being placed on a RamSan70 PCIe card, the results are not encouraging towards the use of the flash cache with a flash based SAN. Review of the AWR results showed that the flash cache was indeed being used but, due to the small difference in overall latency between the RS630 with IB interfaces and the RS70 in the PCIe slot, the overall effect of the flash cache was negligible. The next figure shows the AWR Top Five Events listing both with and without Flash Cache set.

AWR Results
AWR Results
Flash Cache set at 90 GB:
wait % DB
Event Waits Time(s) (ms) time Wait Class
------------------------------ ------------ ----------- ------ ------ ----------
DB CPU 25,339 53.7
log file sync 11,775,317 13,146 1 27.8 Commit
db flash cache single block ph 3,991,869 3,745 1 7.9 User I/O
db file sequential read 6,192,796 3,588 1 7.6 User I/O
latch: cache buffers chains 169,292 251 1 .5 Concurrenc

Flash Cache Set at 0 GB:
wait % DB
Event Waits Time(s) (ms) time Wait Class
------------------------------ ------------ ----------- ------ ------ ----------
DB CPU 26,414 53.9
log file sync 12,139,355 14,138 1 28.9 Commit
db file sequential read 11,548,371 7,373 1 15.0 User I/O
enq: HW - contention 23,317 859 37 1.8 Configurat
latch free 7,922 402 51 .8 Other

Figure 2: AWR Results with and without Flash cache

Disk with Flash Cache
Since the test with a flash utility against an internal PCIe Flash card proved inconclusive we decided to have the lab hook up some disks and re-run the tests using a disk array containing 24-10k 300gb disks for the tables and indexes. The DB_CACHE_SIZE was increased to 50gb and the DB_FLASH_CACHE_SIZE was set to 300gb. Figure 3 shows the results for a disk array with and without a 300gb flash cache.

Figure 3: Disk verse Disk plus Flash Cache Performance

As you can see from reviewing the graph, the Flash cache definitely helped performance at the all levels of our user range. It also showed that with the same hardware the sustained performance increase could be extrapolated to a larger number of users so in the case of using flash cache with disks, yes, performance is gained.

While running this test I had indication that over 160 gigabytes of data blocks were cached in the flash cache. Figure 4 shows the SQL script used to determine flash usage for a single user and Figure 5 shows an example of its output during test runs.

set lines 132 pages 55
col object format a45
select owner||'.'||object_name object,
sum(case when b.status like 'flash%' then 1 end) flash_blocks,
sum(case when b.status like 'flash%' then 0 else 1 end) cache_blocks,
count(*) total_cached_blocks
from v$bh b join dba_objects o
on (objd=object_id)
where owner = upper('&owner')
group by owner, object_name
order by owner,4 asc;

Figure 4: SQL Script to see cached objects for an owner

------------------------- ------------ ------------ -------------------
TPCC.C_CUSTOMER_I1 15249 0 15249
TPCC.C_STOCK_I1 15863 0 15863
TPCC.C_NEW_ORDER_I1 15875 18108 33983
TPCC.C_ORDER_I1 37838 6308 44146
TPCC.WARECLUSTER 63562 450 64012
TPCC.DISTCLUSTER 59511 4504 64015
TPCC.NORDCLUSTER_QUEUE 45764 56100 101864
TPCC.ORDR_UK 94404 40801 135205
TPCC.C_ORDER 123514 67081 190595
TPCC.C_CUSTOMER_I2 202994 51896 254890
TPCC.C_ORDER_LINE_I1 383833 26284 410117
TPCC.C_ORDER_LINE 873325 64108 937433
TPCC.ORDL_UK 1073711 38760 1112471
TPCC.CUSTCLUSTER 1940874 124103 2064977
TPCC.STOKCLUSTER 5508278 3055117 8563395

Figure 5: Example use of Flash Cache
Just to put things in perspective, let’s put the top pure-Flash database results against these disk and Flash cache results. Look at Figure 6.

Figure 6: Flash only, Disk Only and Disk plus Flash Cache Results

In reviewing Figure 6 you should first note it is a logarithmic plot, which means that for each change on the left axis there is a factor of 10 change. This figure shows that using pure flash far outperforms even the best we can expect from a combination of flash and disk. In this case by nearly a factor of 7. The peak performance we obtained from our disk combined with a Flash cache was 1024 TPS, while the peak we obtained in our flash tests (see next section) was over 7000 TPS. Even in previous testing with larger disk arrays (90+ 10K drives), the peak performance I obtained from disk arrays was only in the 2000 TPS range, again showing that SSD technology is superior to any equivalent disk array.