Clues about tables fileformat - Mailing list pgsql-hackers

From Miguel A. Arévalo
Subject Clues about tables fileformat
Date
Msg-id 3C7DFAFD.5070309@marevalo.net
Whole thread Raw
List pgsql-hackers
First of all sorry for posting directly to -hackers without trying it in 
the other lists but I'm pretty sure that this is the place to ask this.

Second, the embarrasing thing, in summary, deleted table, no backup at 
all, neither vacuum so ended with a pretty file with all my datas but no 
clever way to access them.

I've search for this question in the archives and only find a reference 
to "The Tao of Backup" which enlightened me, and will be very useful for 
future reference but doesn't solve my present problem. Also find some 
references for a "not so hard to make" recover utility so...

I'm not a bad C and PERL hacker so I'm trying to contribute this utility 
but havent't found any doc about this file format, I've scanned also 
some of the source code but haven't been able to find any information 
that helps me (I've only studied some parts of the fti contrib module 
before), also tried to do some rev. eng. but this is no the way to go so 
I would be grateful is someone can:

- Point me to some developer doc about this file format.

- Point me to some part of the source code that could be of help, please 
be precise because I'm not very familiar with the tree.

- Or even explain, in summary, something about this file format, or some 
of the bytes needed for me to write this tool.

- Of course, if someone has made or started this tool I will be very 
happy to receive an URL to a .tar.gz ;-) .

On another point, I've been thinking about this tool, and will accept 
hints about this proccess:

- The tool will receive the schema of the table and a copy of the file 
which stores this table, as far I know the schema is not stored in the 
table data file.

- After scanning the file will print a (sorted or filtered by 
transaction id or number of altered rows) list of transactions.

- Ask for a trasaction id and store all the data on a new .sql file much 
like the one generated from a pg_dump.

I think that this is fairly feasible and practical, am I wrong?


So, thanks in advance for your help, and thankyou all for this killer 
application.

P.S.: Please answer also to my email also because I only read pg lists 
by nntp.

Oops, forgot something, I'm talkin about PG 7.1 after that I will port 
it to 7.2 if someone finds it usefull.

Miguel A. Arévalo
marevalo@marevalo.net
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