Github user joshelser commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/277#discussion_r146902970
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/query/ConnectionQueryServicesImpl.java
---
@@ -3101,49 +3124,72 @@ void ensureSystemTablesUpgraded(ReadOnlyProps props)
// Regardless of the case 1 or 2, if the NS does not
exist, we will error expectedly
// below. If the NS does exist and is mapped, the below
check will exit gracefully.
}
-
+
List<TableName> tableNames = getSystemTableNames(admin);
// No tables exist matching "SYSTEM\..*", they are all already
in "SYSTEM:.*"
if (tableNames.size() == 0) { return; }
// Try to move any remaining tables matching "SYSTEM\..*" into
"SYSTEM:"
if (tableNames.size() > 5) {
logger.warn("Expected 5 system tables but found " +
tableNames.size() + ":" + tableNames);
}
+
+ // Try acquiring a lock in SYSMUTEX table before migrating the
tables since it involves disabling the table
+ // If we cannot acquire lock, it means some old client is
either migrating SYSCAT or trying to upgrade the
+ // schema of SYSCAT table and hence it should not be
interrupted
+ acquiredMutexLock = acquireUpgradeMutex(0, mutexRowKey);
+ if(acquiredMutexLock) {
+ logger.debug("Acquired lock in SYSMUTEX table for
migrating SYSTEM tables to SYSTEM namespace");
--- End diff --
Log a debug message for the `else` case too? Easier than finding the lack
of the above message when debugging..
---
