Introduce core.trustPackedRefsStat config
Currently, we always read packed-refs file when 'trustFolderStat'
is false. Introduce a new config 'trustPackedRefsStat' which takes
precedence over 'trustFolderStat' when reading packed refs. Possible
values for this new config are:
* always: Trust packed-refs file attributes
* after_open: Same as 'always', but refresh the file attributes of
packed-refs before trusting it
* never: Always read the packed-refs file
* unset: Fallback to 'trustFolderStat' to determine if the file
attributes of packed-refs can be trusted
Folks whose repositories are on NFS and have traditionally been
setting 'trustFolderStat=false' can now get some performance improvement
with 'trustPackedRefsStat=after_open' as it refreshes the file
attributes of packed-refs (at least on some NFS clients) before
considering it.
For example, consider a repository on NFS with ~500k packed-refs. Here
are some stats which illustrate the improvement with this new config
when reading packed refs on NFS:
trustFolderStat=true trustPackedRefsStat=unset: 0.2ms
trustFolderStat=false trustPackedRefsStat=unset: 155ms
trustFolderStat=false trustPackedRefsStat=after_open: 1.5ms
Change-Id: I00da88e4cceebbcf3475be0fc0011ff65767c111
Signed-off-by: Kaushik Lingarkar <quic_kaushikl@quicinc.com>
diff --git a/Documentation/config-options.md b/Documentation/config-options.md
index 6551ba8..9cb3c62 100644
--- a/Documentation/config-options.md
+++ b/Documentation/config-options.md
@@ -46,6 +46,7 @@
| `core.supportsAtomicFileCreation` | `true` | ⃞ | Whether the filesystem supports atomic file creation. |
| `core.symlinks` | Auto detect if filesystem supports symlinks| ✅ | If false, symbolic links are checked out as small plain files that contain the link text. |
| `core.trustFolderStat` | `true` | ⃞ | Whether to trust the pack folder's and packed-refs file's file attributes (Java equivalent of stat command on *nix). When looking for pack files, if `false` JGit will always scan the `.git/objects/pack` folder and if set to `true` it assumes that pack files are unchanged if the file attributes of the pack folder are unchanged. When getting the list of packed refs, if `false` JGit will always read the packed-refs file and if set to `true` it uses the file attributes of the packed-refs file and will only read it if a file attribute has changed. Setting this option to `false` can help to workaround caching issues on NFS, but reduces performance.|
+| `core.trustPackedRefsStat` | `unset` | ⃞ | Whether to trust the file attributes (Java equivalent of stat command on *nix) of the packed-refs file. If `never` JGit will ignore the file attributes of the packed-refs file and always read it. If `always` JGit will trust the file attributes of the packed-refs file and will only read it if a file attribute has changed. `after_open` behaves the same as `always`, except that the packed-refs file is opened and closed before its file attributes are considered. An open/close of the packed-refs file is known to refresh its file attributes, at least on some NFS clients. If `unset`, JGit will use the behavior described in `trustFolderStat`. |
| `core.worktree` | Root directory of the working tree if it is not the parent directory of the `.git` directory | ✅ | The path to the root of the working tree. |
## __gc__ options
diff --git a/org.eclipse.jgit/.settings/.api_filters b/org.eclipse.jgit/.settings/.api_filters
index a6f1831..0f84330 100644
--- a/org.eclipse.jgit/.settings/.api_filters
+++ b/org.eclipse.jgit/.settings/.api_filters
@@ -15,6 +15,20 @@
<message_argument value="SHA1_IMPLEMENTATION"/>
</message_arguments>
</filter>
+ <filter id="1142947843">
+ <message_arguments>
+ <message_argument value="6.1.1"/>
+ <message_argument value="CONFIG_KEY_TRUST_PACKED_REFS_STAT"/>
+ </message_arguments>
+ </filter>
+ </resource>
+ <resource path="src/org/eclipse/jgit/lib/CoreConfig.java" type="org.eclipse.jgit.lib.CoreConfig$TrustPackedRefsStat">
+ <filter id="1142947843">
+ <message_arguments>
+ <message_argument value="6.1.1"/>
+ <message_argument value="TrustPackedRefsStat"/>
+ </message_arguments>
+ </filter>
</resource>
<resource path="src/org/eclipse/jgit/lib/ObjectDatabase.java" type="org.eclipse.jgit.lib.ObjectDatabase">
<filter id="336695337">
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
index b46ffe3..43ebce3 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
@@ -30,6 +30,7 @@
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
+import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.InterruptedIOException;
import java.nio.file.DirectoryNotEmptyException;
@@ -60,6 +61,7 @@
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.ConfigConstants;
import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.CoreConfig.TrustPackedRefsStat;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectIdRef;
import org.eclipse.jgit.lib.Ref;
@@ -892,10 +894,37 @@ PackedRefList getPackedRefs() throws IOException {
boolean trustFolderStat = getRepository().getConfig().getBoolean(
ConfigConstants.CONFIG_CORE_SECTION,
ConfigConstants.CONFIG_KEY_TRUSTFOLDERSTAT, true);
+ TrustPackedRefsStat trustPackedRefsStat =
+ getRepository().getConfig().getEnum(
+ ConfigConstants.CONFIG_CORE_SECTION,
+ null,
+ ConfigConstants.CONFIG_KEY_TRUST_PACKED_REFS_STAT,
+ TrustPackedRefsStat.UNSET);
final PackedRefList curList = packedRefs.get();
- if (trustFolderStat && !curList.snapshot.isModified(packedRefsFile)) {
- return curList;
+
+ switch (trustPackedRefsStat) {
+ case NEVER:
+ break;
+ case AFTER_OPEN:
+ try (InputStream stream = Files
+ .newInputStream(packedRefsFile.toPath())) {
+ // open the file to refresh attributes (on some NFS clients)
+ } catch (FileNotFoundException e) {
+ // Ignore as packed-refs may not exist
+ }
+ //$FALL-THROUGH$
+ case ALWAYS:
+ if (!curList.snapshot.isModified(packedRefsFile)) {
+ return curList;
+ }
+ break;
+ case UNSET:
+ if (trustFolderStat
+ && !curList.snapshot.isModified(packedRefsFile)) {
+ return curList;
+ }
+ break;
}
final PackedRefList newList = readPackedRefs();
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigConstants.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigConstants.java
index 649bcde..9398419 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigConstants.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigConstants.java
@@ -850,4 +850,10 @@ public final class ConfigConstants {
*/
public static final String CONFIG_KEY_ABBREV = "abbrev";
+ /**
+ * The "trustPackedRefsStat" key
+ *
+ * @since 6.1.1
+ */
+ public static final String CONFIG_KEY_TRUST_PACKED_REFS_STAT = "trustPackedRefsStat";
}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/CoreConfig.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/CoreConfig.java
index f23c6e0..fc82a5f 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/CoreConfig.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/CoreConfig.java
@@ -116,6 +116,27 @@ public enum LogRefUpdates {
ALWAYS
}
+ /**
+ * Permissible values for {@code core.trustPackedRefsStat}.
+ *
+ * @since 6.1.1
+ */
+ public enum TrustPackedRefsStat {
+ /** Do not trust file attributes of the packed-refs file. */
+ NEVER,
+
+ /** Trust file attributes of the packed-refs file. */
+ ALWAYS,
+
+ /** Open and close the packed-refs file to refresh its file attributes
+ * and then trust it. */
+ AFTER_OPEN,
+
+ /** {@code core.trustPackedRefsStat} defaults to this when it is
+ * not set */
+ UNSET
+ }
+
private final int compression;
private final int packIndexVersion;
