Re: A performance tip

--On Thursday, January 23, 2003 12:14 PM -0500 Neil Schemenauer
nas@mems-exchange.org wrote:

 Before running svnadmin load or svnadmin recover, add set_flags
 DB_TXN_NOSYNC in the DB_CONFIG file. It gives a massive speed
 increase. Remember to remove it after since I'm not sure if it's
 safe.

 Could svnadmin set the flag itself? It stupid for it to do
 millions of fsync calls while running instead a handful when it
 completes. Try running strace on svnserve, svnadmin or the apache.
 The number of fsync calls made is truly staggering.

Yeah, the fact that BDB does an fsync() after every transaction is a
massive performance problem overall. (Consider we do a transaction
for every value retrieved, etc.)

I think the better/best thing to do would be to do this recovery in
one transaction. I have a hunch that this isn't possible given the
current state of libsvn_fs. What we'd potentially lose in atomicity
(by having larger-grained txn's), we'll gain in speed.

I'm starting to think some of our transactions are a bit too
fine-grained and we're getting killed by the fact that they are
ridiculously expensive in BDB.

C-Mike? -- justin

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Received on Sat Oct 14 02:09:35 2006