Aaron Schulz has uploaded a new change for review.
https://gerrit.wikimedia.org/r/300759
Change subject: Make onTransactionPreCommitOrIdle() atomic when immediate
......................................................................
Make onTransactionPreCommitOrIdle() atomic when immediate
One of the main uses of this method is to tack on some DB
updates to the end of atomic transactions to reduce lock
contention problems. In this case, multiple updates in the
callback are atomic. However, if no transaction is active,
then such updates were previously not atomic. Wrap them in
transactions now.
Change-Id: I18c56e65063a61000c4dfd1979bf972800b173ac
---
M includes/db/Database.php
M includes/db/IDatabase.php
2 files changed, 9 insertions(+), 5 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/mediawiki/core
refs/changes/59/300759/1
diff --git a/includes/db/Database.php b/includes/db/Database.php
index 9b73584..91517b5 100644
--- a/includes/db/Database.php
+++ b/includes/db/Database.php
@@ -2468,7 +2468,10 @@
if ( $this->mTrxLevel ) {
$this->mTrxPreCommitCallbacks[] = [ $callback,
wfGetCaller() ];
} else {
- $this->onTransactionIdle( $callback ); // this will
trigger immediately
+ // If no transaction is active, then make one for this
callback
+ $this->begin( __METHOD__ );
+ call_user_func( $callback );
+ $this->commit( __METHOD__ );
}
}
diff --git a/includes/db/IDatabase.php b/includes/db/IDatabase.php
index c024632..aa2a980 100644
--- a/includes/db/IDatabase.php
+++ b/includes/db/IDatabase.php
@@ -1221,7 +1221,7 @@
public function getMasterPos();
/**
- * Run an anonymous function as soon as the current transaction commits
or rolls back.
+ * Run a callback as soon as the current transaction commits or rolls
back.
* An error is thrown if no transaction is pending. Queries in the
function will run in
* AUTO-COMMIT mode unless there are begin() calls. Callbacks must
commit any transactions
* that they begin.
@@ -1238,7 +1238,7 @@
public function onTransactionResolution( callable $callback );
/**
- * Run an anonymous function as soon as there is no transaction pending.
+ * Run a callback as soon as there is no transaction pending.
* If there is a transaction and it is rolled back, then the callback
is cancelled.
* Queries in the function will run in AUTO-COMMIT mode unless there
are begin() calls.
* Callbacks must commit any transactions that they begin.
@@ -1259,9 +1259,10 @@
public function onTransactionIdle( callable $callback );
/**
- * Run an anonymous function before the current transaction commits or
now if there is none.
+ * Run a callback before the current transaction commits or now if
there is none.
* If there is a transaction and it is rolled back, then the callback
is cancelled.
- * Callbacks must not start nor commit any transactions.
+ * Callbacks must not start nor commit any transactions. If no
transaction is active,
+ * then a transaction will wrap the callback.
*
* This is useful for updates that easily cause deadlocks if locks are
held too long
* but where atomicity is strongly desired for these updates and some
related updates.
--
To view, visit https://gerrit.wikimedia.org/r/300759
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I18c56e65063a61000c4dfd1979bf972800b173ac
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Aaron Schulz <asch...@wikimedia.org>
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