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Paul C

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I used to manage database geeks. Lovely people once you get to understand their language

 

There will be approximately twenty seven specific errors in what I said, all highly significant to database folk, none of which will make much odds to users

 

Richard

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Basically the database was trashed from last week's full disk issue - the information_schema didn't reconcile with the underlying .MYD and .MYI files. Last Monday, we eventually got the database up and running reasonably well, albeit with a number of outstanding issues which meant certain admin tasks (such as merging members) couldn't be done. Also there was a chance that the weekly automatic repair/optimise had in fact further damaged it, preventing a backup. The longer it was left, the more data we'd lose. So the database was issue was resolved and stitched together this morning using a little bit from a backup we had by chance kept before xmas, but mostly all the important data kept without loss.

 

Ah, splendid.

 

At least MySQL is happy to play that game.

 

I once spent a VERY tense week trying to fix a broken Oracle database.

 

Oracle has this endearing feature of protecting you from yourself.

 

Can't recall all the details, but basically, it had crashed during a commit and the rollback was corrupt, which meant that the tables were in an unknown and inconsistent state. I knew exactly what data was in flight.

 

The database backup then turned out to be corrupt, and couldn't be restored.

 

So the resolution was simple. Accept that the database was inconsistent, delete all the in-flight transactions that were affected, take a good backup, and off we go.

 

Not so.

 

Oracle was having none of it.

 

"that database is corrupt, you don't want it"

 

"Yes I do, its the best we have"

 

"Restore from a backup"

 

"I don't have a backup"

 

Took bloody hours manually dumping tables, then creating a new database to load them into.

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I have a rather nice book on the history of LEO (Lyons Electronic Office, I think, as in Lyons Tea Shops), if you want to borrow it. https://en.wikipedia.org/wiki/LEO_(computer)

 

One point about Joe Lyons' innovative use of a computer fro business use was that they used mark sensing readers to collect the data from the tea shops.

Leo would print out the delivery sheets for each tea shop and the driver would mark the items when delivered. Although it was an awful long time ago - I think the clever thing (well it was then) that the delivery slip also captured the reorder quantities as well.

J.L at Cadby Hall (sounds grand doesn't it) ran trips around the factory for school kids - I went 'cos you got free ice creams - and ended up passing through Leo's umm- office. Being inquisitive I asked the leader "what's that funny paper" and he waxed lyrical about the system.

 

IIRC Leo was before punched cards and the only means of input was (ugh) paper tape - so early OCR really was revolutionary.

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Sir, sir, ive got a topic I can bore people rigid with, bet you can't work out what it is wink.png

 

I wouldn't be bored! I'm a tree geek too! In fact only the other day I was able to inform my neighbour that the tree which blew down and almost killed one of his cows wasn't a Picea abies as he had told me, but an Abies alba! He wasn't impressed.

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One point about Joe Lyons' innovative use of a computer fro business use was that they used mark sensing readers to collect the data from the tea shops.

Leo would print out the delivery sheets for each tea shop and the driver would mark the items when delivered. Although it was an awful long time ago - I think the clever thing (well it was then) that the delivery slip also captured the reorder quantities as well.

J.L at Cadby Hall (sounds grand doesn't it) ran trips around the factory for school kids - I went 'cos you got free ice creams - and ended up passing through Leo's umm- office. Being inquisitive I asked the leader "what's that funny paper" and he waxed lyrical about the system.

 

IIRC Leo was before punched cards and the only means of input was (ugh) paper tape - so early OCR really was revolutionary.

I think you mean OMR on the last line. The early Optical Mark Readers (OMR) could sense the presence of a mark in certain locations on a form. Optical Character Readers came much later.

 

London Transport used OMR back in the late 60's for bus timesheets. The forms had several boxes for each digit or letter and were quite hard to fill out. For example, to represent the number 7 you would have to put a mark in the 1 and 2 and 4 boxes (octal - geddit!).

 

The OCR readers were notoriously unreliably and had to be fettled by engineers prior to weekly use. Even then, they would chew up forms or misread the data.

 

Not sure if early LEO's supported card readers but I worked with an old LEO III in the early 70's that did.

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