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* Wrap calls to registerSubstitute() in a single transaction to

Browse source 
improve throughput.
* Don't build the `substitute-rev' table for now, since it caused
  Theta(N^2) time and log file consumption when adding N substitutes.
  Maybe we can do without it.
This commit is contained in:
Eelco Dolstra 2004-06-21 07:38:17 +00:00
parent 15c60ca1b6
commit daf0a923c7
3 changed files with 13 additions and 11 deletions
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12
src/libstore/store.cc
View file

@ -302,19 +302,16 @@ static void writeSubstitutes(const Transaction & txn,
}
void registerSubstitute(const Path & srcPath,
const Substitute & sub)
void registerSubstitute(const Transaction & txn,
const Path & srcPath, const Substitute & sub)
{
assertStorePath(srcPath);
assertStorePath(sub.storeExpr);
Transaction txn(nixDB);
Substitutes subs = readSubstitutes(txn, srcPath);
if (find(subs.begin(), subs.end(), sub) != subs.end()) {
/* Nothing to do if the substitute is already known. */
txn.abort();
return;
}
subs.push_front(sub); /* new substitutes take precedence */
@ -326,9 +323,8 @@ void registerSubstitute(const Path & srcPath,
if (find(revs.begin(), revs.end(), srcPath) == revs.end())
revs.push_back(srcPath);
nixDB.setStrings(txn, dbSubstitutesRev, sub.storeExpr, revs);
txn.commit();
// !!! O(n^2) complexity in building this
// nixDB.setStrings(txn, dbSubstitutesRev, sub.storeExpr, revs);
}

4
src/libstore/store.hh
View file

@ -63,8 +63,8 @@ bool querySuccessor(const Path & srcPath, Path & sucPath);
Paths queryPredecessors(const Path & sucPath);
/* Register a substitute. */
void registerSubstitute(const Path & srcPath,
const Substitute & sub);
void registerSubstitute(const Transaction & txn,
const Path & srcPath, const Substitute & sub);
/* Return the substitutes expression for the given path. */
Substitutes querySubstitutes(const Path & srcPath);

8
src/nix-store/main.cc
View file

@ -170,6 +170,9 @@ static void opSubstitute(Strings opFlags, Strings opArgs)
if (!opArgs.empty())
throw UsageError("no arguments expected");
Transaction txn;
createStoreTransaction(txn);
while (1) {
Path srcPath;
Substitute sub;
@ -188,8 +191,11 @@ static void opSubstitute(Strings opFlags, Strings opArgs)
sub.args.push_back(s);
}
if (!cin || cin.eof()) throw Error("missing input");
registerSubstitute(srcPath, sub);
cerr << ".";
registerSubstitute(txn, srcPath, sub);
}
txn.commit();
}