opendev/gerrit
Code Issues Proposed changes

Shard refs/starred-changes refs by change ID instead of account ID

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If the ref is sharded by change ID, the lookup by change ID is
cheaper. This is because now we can list all refs that start with
refs/starred-changes/ plus sharded change ID and looking up refs with
a prefix that end on '/' is optimized in jgit.

Finding all changes that were starred by a user gets more expensive
since now we need to scan the complete refs/starred-changes/ namespace
for this.

The ref format is changed, because we plan to store the users that
have starred a change in the change index, and this means that we need
to look them up each time a change is reindex. If reindexing a change
would require a complete scan over the refs/starred-changes/ namespace
this would result in performance issues.

On the other hand looking up the changes that were starred by a user
can be done via the change index so that we don't need to scan the
refs/starred-changes/ namespace in this case either.

Change-Id: Ib81d46283035ef753d35fbc78684ded9f074bd1f
Signed-off-by: Edwin Kempin <ekempin@google.com>
This commit is contained in:
Edwin Kempin
2016-04-15 16:34:33 +02:00
parent 82d3bfa84c
commit dfe73dc408
3 changed files with 31 additions and 30 deletions
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23
gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RefNames.java
View File

@@ -95,37 +95,36 @@ public class RefNames {
public static String refsDraftComments(Account.Id accountId,
Change.Id changeId) {
StringBuilder r = buildRefsPrefix(REFS_DRAFT_COMMENTS, accountId);
StringBuilder r = buildRefsPrefix(REFS_DRAFT_COMMENTS, accountId.get());
r.append(changeId.get());
return r.toString();
}
public static String refsDraftCommentsPrefix(Account.Id accountId) {
return buildRefsPrefix(REFS_DRAFT_COMMENTS, accountId).toString();
return buildRefsPrefix(REFS_DRAFT_COMMENTS, accountId.get()).toString();
}
public static String refsStarredChanges(Account.Id accountId,
Change.Id changeId) {
StringBuilder r = buildRefsPrefix(REFS_STARRED_CHANGES, accountId);
r.append(changeId.get());
public static String refsStarredChanges(Change.Id changeId,
Account.Id accountId) {
StringBuilder r = buildRefsPrefix(REFS_STARRED_CHANGES, changeId.get());
r.append(accountId.get());
return r.toString();
}
public static String refsStarredChangesPrefix(Account.Id accountId) {
return buildRefsPrefix(REFS_STARRED_CHANGES, accountId).toString();
public static String refsStarredChangesPrefix(Change.Id changeId) {
return buildRefsPrefix(REFS_STARRED_CHANGES, changeId.get()).toString();
}
private static StringBuilder buildRefsPrefix(String prefix,
Account.Id accountId) {
private static StringBuilder buildRefsPrefix(String prefix, int id) {
StringBuilder r = new StringBuilder();
r.append(prefix);
int n = accountId.get() % 100;
int n = id % 100;
if (n < 10) {
r.append('0');
}
r.append(n);
r.append('/');
r.append(accountId.get());
r.append(id);
r.append('/');
return r;
}