From 772778c0eced8f8d63bfe6b1e9801ad6aada65bf Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Tue, 11 Dec 2012 11:49:42 +0100 Subject: [PATCH] On SQLITE_BUSY, wait a random amount of time If all contending processes wait a fixed amount of time (100 ms), there is a good probability that they'll just collide again. --- src/libmain/shared.cc | 6 ++++++ src/libstore/local-store.cc | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc index ead3fc017..e869ef037 100644 --- a/src/libmain/shared.cc +++ b/src/libmain/shared.cc @@ -10,6 +10,7 @@ #include #include +#include #include #include @@ -135,6 +136,11 @@ static void initAndRun(int argc, char * * argv) everybody. */ umask(0022); + /* Initialise the PRNG. */ + struct timeval tv; + gettimeofday(&tv, 0); + srandom(tv.tv_usec); + /* Process the NIX_LOG_TYPE environment variable. */ string lt = getEnv("NIX_LOG_TYPE"); if (lt != "") setLogType(lt); diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc index b4fc64d71..26b4cfd8c 100644 --- a/src/libstore/local-store.cc +++ b/src/libstore/local-store.cc @@ -48,7 +48,7 @@ static void throwSQLiteError(sqlite3 * db, const format & f) #if HAVE_NANOSLEEP struct timespec t; t.tv_sec = 0; - t.tv_nsec = 100 * 1000 * 1000; /* 0.1s */ + t.tv_nsec = (random() % 100) * 1000 * 1000; /* <= 0.1s */ nanosleep(&t, 0); #else sleep(1);