Automatically optimise the Nix store when a new path is added

Auto-optimisation is enabled by default.  It can be turned off by
setting auto-optimise-store to false in nix.conf.
This commit is contained in:
Eelco Dolstra 2012-07-23 15:02:52 -04:00
parent 564fb7d9fa
commit 6193105710
5 changed files with 45 additions and 10 deletions

View file

@ -337,7 +337,20 @@ build-use-chroot = /dev /proc /bin</programlisting>
<literal>true</literal>.</para></listitem>
</varlistentry>
<varlistentry><term><literal>auto-optimise-store</literal></term>
<listitem><para>If set to <literal>true</literal> (the default),
Nix automatically detects files in the store that have identical
contents, and replaces them with hard links to a single copy.
This saves disk space. If set to <literal>false</literal>, you
can still run <command>nix-store --optimise</command> to get rid
of duplicate files.</para></listitem>
</varlistentry>
</variablelist>
</para>

View file

@ -2093,6 +2093,8 @@ void DerivationGoal::computeClosure()
if (allowed.find(*i) == allowed.end())
throw BuildError(format("output is not allowed to refer to path `%1%'") % *i);
}
worker.store.optimisePath(path); // FIXME: combine with scanForReferences()
}
/* Register each output path as valid, and register the sets of
@ -2546,6 +2548,8 @@ void SubstitutionGoal::finished()
HashResult hash = hashPath(htSHA256, storePath);
worker.store.optimisePath(storePath); // FIXME: combine with hashPath()
ValidPathInfo info2;
info2.path = storePath;
info2.hash = hash.first;

View file

@ -209,6 +209,7 @@ LocalStore::LocalStore(bool reserveSpace)
/* Create missing state directories if they don't already exist. */
createDirs(nixStore);
createDirs(linksDir = nixStore + "/.links");
Path profilesDir = nixStateDir + "/profiles";
createDirs(nixStateDir + "/profiles");
createDirs(nixStateDir + "/temproots");
@ -1116,6 +1117,8 @@ Path LocalStore::addToStoreFromDump(const string & dump, const string & name,
hash.second = dump.size();
} else
hash = hashPath(htSHA256, dstPath);
optimisePath(dstPath); // FIXME: combine with hashPath()
ValidPathInfo info;
info.path = dstPath;
@ -1170,6 +1173,8 @@ Path LocalStore::addTextToStore(const string & name, const string & s,
canonicalisePathMetaData(dstPath);
HashResult hash = hashPath(htSHA256, dstPath);
optimisePath(dstPath);
ValidPathInfo info;
info.path = dstPath;
@ -1405,6 +1410,8 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
/* !!! if we were clever, we could prevent the hashPath()
here. */
HashResult hash = hashPath(htSHA256, dstPath);
optimisePath(dstPath); // FIXME: combine with hashPath()
ValidPathInfo info;
info.path = dstPath;

View file

@ -85,6 +85,8 @@ private:
typedef std::map<Path, RunningSubstituter> RunningSubstituters;
RunningSubstituters runningSubstituters;
Path linksDir;
public:
@ -169,6 +171,9 @@ public:
files with the same contents. */
void optimiseStore(OptimiseStats & stats);
/* Optimise a single store path. */
void optimisePath(const Path & path);
/* Check the integrity of the Nix store. */
void verifyStore(bool checkContents);
@ -267,6 +272,8 @@ private:
Path importPath(bool requireSignature, Source & source);
void checkDerivationOutputs(const Path & drvPath, const Derivation & drv);
void optimisePath_(OptimiseStats & stats, const Path & path);
};

View file

@ -49,10 +49,7 @@ struct MakeImmutable
};
const string linksDir = ".links";
static void hashAndLink(OptimiseStats & stats, const Path & path)
void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path)
{
struct stat st;
if (lstat(path.c_str(), &st))
@ -61,7 +58,7 @@ static void hashAndLink(OptimiseStats & stats, const Path & path)
if (S_ISDIR(st.st_mode)) {
Strings names = readDirectory(path);
foreach (Strings::iterator, i, names)
hashAndLink(stats, path + "/" + *i);
optimisePath_(stats, path + "/" + *i);
return;
}
@ -91,7 +88,7 @@ static void hashAndLink(OptimiseStats & stats, const Path & path)
printMsg(lvlDebug, format("`%1%' has hash `%2%'") % path % printHash(hash));
/* Check if this is a known hash. */
Path linkPath = nixStore + "/" + linksDir + "/" + printHash32(hash);
Path linkPath = linksDir + "/" + printHash32(hash);
if (!pathExists(linkPath)) {
/* Nope, create a hard link in the links directory. */
@ -177,15 +174,22 @@ static void hashAndLink(OptimiseStats & stats, const Path & path)
void LocalStore::optimiseStore(OptimiseStats & stats)
{
createDirs(nixStore + "/" + linksDir);
PathSet paths = queryValidPaths();
foreach (PathSet::iterator, i, paths) {
addTempRoot(*i);
if (!isValidPath(*i)) continue; /* path was GC'ed, probably */
startNest(nest, lvlChatty, format("hashing files in `%1%'") % *i);
hashAndLink(stats, *i);
optimisePath_(stats, *i);
}
}
void LocalStore::optimisePath(const Path & path)
{
if (queryBoolSetting("auto-optimise-store", true)) {
OptimiseStats stats;
optimisePath_(stats, path);
}
}