Hello, I'm working on a simple db. Each record is composed of 3 long values. The first two are the primary key.
I have to measure the performance of the insertions. Each insertion is wrapped in a transaction, which is commited having only one insertion in it. I've measured both berkeley db performance and postgres and got about 110-115 insertions per second. Now in derby db (both in embeded mode and server mode) I get better performance: about 250-300 insertions per second. This obviously results from some kind of a group commit, although I get these results both when auto-commiting or manual-commiting after each insertion. I've performed a simple test of synchronious writing 24 bytes (3 * 8 bytes) to the disk. It measure 117 writes per second, and I believe this is the upper bound of any db performance. So, I don't understand why I get such good performance, although I commit after each insertion. I examined the .dat files in both /log and /seg0 folders. None of them increase in 24 bytes segments, but rathar bigger segments. So, my questions are: 1. Which log file in /log or /seg0 should I examine to analyze the numebr of bytes written each write to disk? 2. How do I disable the group commit or whatever attribute that causes this communal write? how do I make each transaction be written on its own to the disk? Thanks in advance, Yaron -- View this message in context: http://www.nabble.com/Derby-db---need-to-disable-improved-performance-tf3796921.html#a10739876 Sent from the Apache Derby Users mailing list archive at Nabble.com.
