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Posted to pr@cassandra.apache.org by GitBox <gi...@apache.org> on 2022/01/02 14:55:41 UTC
[GitHub] [cassandra] pauloricardomg commented on a change in pull request #1354: [16436] - Added startup check for read_ahead_kb setting.
pauloricardomg commented on a change in pull request #1354:
URL: https://github.com/apache/cassandra/pull/1354#discussion_r777216698
##########
File path: src/java/org/apache/cassandra/service/StartupChecks.java
##########
@@ -498,23 +573,45 @@ public void execute() throws StartupException
throw new StartupException(StartupException.ERR_WRONG_CONFIG, errMsg.get());
};
+ @VisibleForTesting
+ public static String getReadAheadKBPath(String blockDirectoryPath)
+ {
+ String readAheadKBPath = null;
+
+ final String READ_AHEAD_KB_SETTING_PATH = "/sys/block/%s/queue/read_ahead_kb";
+ try
+ {
+ String deviceName = blockDirectoryPath.split("/")[2].replaceAll("[0-9]*$", "");
+
+ if (StringUtils.isNotEmpty(deviceName))
+ {
+ readAheadKBPath = String.format(READ_AHEAD_KB_SETTING_PATH, deviceName);
+ }
+ }
+ catch (Exception e)
+ {
+ logger.error("Error retrieving device path for {}.", blockDirectoryPath);
+ }
+
+ return readAheadKBPath;
+ }
+
@VisibleForTesting
static Optional<String> checkLegacyAuthTablesMessage()
{
List<String> existing = new ArrayList<>(SchemaConstants.LEGACY_AUTH_TABLES).stream().filter((legacyAuthTable) ->
- {
- UntypedResultSet result = QueryProcessor.executeOnceInternal(String.format("SELECT table_name FROM %s.%s WHERE keyspace_name='%s' AND table_name='%s'",
- SchemaConstants.SCHEMA_KEYSPACE_NAME,
- "tables",
- SchemaConstants.AUTH_KEYSPACE_NAME,
- legacyAuthTable));
- return result != null && !result.isEmpty();
- }).collect(Collectors.toList());
+ {
+ UntypedResultSet result = QueryProcessor.executeOnceInternal(String.format("SELECT table_name FROM %s.%s WHERE keyspace_name='%s' AND table_name='%s'",
+ SchemaConstants.SCHEMA_KEYSPACE_NAME, "tables", SchemaConstants.AUTH_KEYSPACE_NAME, legacyAuthTable));
+ return result != null && !result.isEmpty();
+ }).collect(Collectors.toList());
if (!existing.isEmpty())
return Optional.of(String.format("Legacy auth tables %s in keyspace %s still exist and have not been properly migrated.",
- Joiner.on(", ").join(existing), SchemaConstants.AUTH_KEYSPACE_NAME));
+ Joiner.on(", ").join(existing), SchemaConstants.AUTH_KEYSPACE_NAME));
Review comment:
Please remove unrelated formatting change.
##########
File path: test/unit/org/apache/cassandra/service/StartupChecksTest.java
##########
@@ -103,6 +103,30 @@ public void compatibilityCheckIgnoresNonDbFiles() throws Exception
startupChecks.verify();
}
+ @Test
+ public void checkReadAheadKbSettingCheck() throws Exception
+ {
+ // This test just validates if the verify function
+ // doesn't throw any exceptions
+ startupChecks = startupChecks.withTest(StartupChecks.checkReadAheadKbSetting);
+ startupChecks.verify();
+ }
+
+ @Test
+ public void getReadAheadKBPath()
+ {
+ startupChecks = startupChecks.withTest(StartupChecks.checkReadAheadKbSetting);
+
+ String sdaDirectory = startupChecks.getReadAheadKBPath("/dev/sda12");
Review comment:
use `StartupChecks.getReadAheadKBPath` to make explicit this is an static method.
##########
File path: test/unit/org/apache/cassandra/service/StartupChecksTest.java
##########
@@ -103,6 +103,30 @@ public void compatibilityCheckIgnoresNonDbFiles() throws Exception
startupChecks.verify();
}
+ @Test
+ public void checkReadAheadKbSettingCheck() throws Exception
+ {
+ // This test just validates if the verify function
+ // doesn't throw any exceptions
+ startupChecks = startupChecks.withTest(StartupChecks.checkReadAheadKbSetting);
+ startupChecks.verify();
+ }
+
+ @Test
+ public void getReadAheadKBPath()
Review comment:
call this `testGetReadAheadKBPath`
##########
File path: src/java/org/apache/cassandra/service/StartupChecks.java
##########
@@ -498,23 +573,45 @@ public void execute() throws StartupException
throw new StartupException(StartupException.ERR_WRONG_CONFIG, errMsg.get());
};
+ @VisibleForTesting
+ public static String getReadAheadKBPath(String blockDirectoryPath)
+ {
+ String readAheadKBPath = null;
+
+ final String READ_AHEAD_KB_SETTING_PATH = "/sys/block/%s/queue/read_ahead_kb";
+ try
+ {
+ String deviceName = blockDirectoryPath.split("/")[2].replaceAll("[0-9]*$", "");
+
+ if (StringUtils.isNotEmpty(deviceName))
+ {
+ readAheadKBPath = String.format(READ_AHEAD_KB_SETTING_PATH, deviceName);
+ }
+ }
+ catch (Exception e)
+ {
+ logger.error("Error retrieving device path for {}.", blockDirectoryPath);
+ }
+
+ return readAheadKBPath;
+ }
+
@VisibleForTesting
static Optional<String> checkLegacyAuthTablesMessage()
{
List<String> existing = new ArrayList<>(SchemaConstants.LEGACY_AUTH_TABLES).stream().filter((legacyAuthTable) ->
- {
- UntypedResultSet result = QueryProcessor.executeOnceInternal(String.format("SELECT table_name FROM %s.%s WHERE keyspace_name='%s' AND table_name='%s'",
- SchemaConstants.SCHEMA_KEYSPACE_NAME,
- "tables",
- SchemaConstants.AUTH_KEYSPACE_NAME,
- legacyAuthTable));
- return result != null && !result.isEmpty();
- }).collect(Collectors.toList());
+ {
Review comment:
Please remove unrelated formatting change.
##########
File path: src/java/org/apache/cassandra/service/StartupChecks.java
##########
@@ -285,6 +289,77 @@ public void execute()
}
};
+ public static final StartupCheck checkReadAheadKbSetting = new StartupCheck()
+ {
+ // This value is in KB.
+ private static final long MAX_RECOMMENDED_READ_AHEAD_KB_SETTING = 128;
+
+ @Override
+ public void execute() throws StartupException
+ {
+ if (!FBUtilities.isLinux)
+ return;
+
+ String[] dataDirectories = DatabaseDescriptor.getRawConfig().data_file_directories;
+ Map<String, String> blockDevices = new HashMap<String, String>();
+ for (String dataDirectory : dataDirectories)
+ {
+ try
+ {
+ Path p = Path.of(dataDirectory);
+ FileStore fs = Files.getFileStore(p);
+
+ String blockDirectory = fs.name();
+ if(StringUtils.isNotEmpty(blockDirectory))
+ {
+ blockDevices.put(blockDirectory, dataDirectory);
+ }
+ }
+ catch (IOException e)
+ {
+ logger.warn("IO exception while reading file {}.", dataDirectory, e);
+ }
+ }
+ for (Map.Entry<String, String> entry: blockDevices.entrySet())
+ {
+ String blockDeviceDirectory = entry.getKey();
+ String dataDirectory = entry.getValue();
+ try
+ {
+
+ String readAheadKBPath = StartupChecks.getReadAheadKBPath(blockDeviceDirectory);
+
+ final BufferedReader bufferedReader = Files.newBufferedReader(Path.of(readAheadKBPath));
Review comment:
Perhaps we can have a slightly more succint check:
```
Path readAheadKBPath = StartupChecks.getReadAheadKBPath(blockDeviceDirectory);
if (readAheadKBPath != null && Files.exists(readAheadKBPath))
{
int readAheadKbSetting = Ints.fromBytesArray(Files.readAllBytes(readAheadKBPath));
// perform check
}
```
wdyt?
##########
File path: src/java/org/apache/cassandra/service/StartupChecks.java
##########
@@ -243,8 +247,8 @@ private void checkOutOfMemoryHandling()
{
if (!jvmOptionsContainsOneOf("-XX:OnOutOfMemoryError="))
logger.warn("The JVM is not configured to stop on OutOfMemoryError which can cause data corruption."
- + " Either upgrade your JRE to a version greater or equal to 8u92 and use -XX:+ExitOnOutOfMemoryError/-XX:+CrashOnOutOfMemoryError"
- + " or use -XX:OnOutOfMemoryError=\"<cmd args>;<cmd args>\" on your current JRE.");
+ + " Either upgrade your JRE to a version greater or equal to 8u92 and use -XX:+ExitOnOutOfMemoryError/-XX:+CrashOnOutOfMemoryError"
Review comment:
Please remove unrelated formatting change.
##########
File path: src/java/org/apache/cassandra/service/StartupChecks.java
##########
@@ -285,6 +289,77 @@ public void execute()
}
};
+ public static final StartupCheck checkReadAheadKbSetting = new StartupCheck()
+ {
+ // This value is in KB.
+ private static final long MAX_RECOMMENDED_READ_AHEAD_KB_SETTING = 128;
+
+ @Override
+ public void execute() throws StartupException
+ {
+ if (!FBUtilities.isLinux)
+ return;
+
+ String[] dataDirectories = DatabaseDescriptor.getRawConfig().data_file_directories;
+ Map<String, String> blockDevices = new HashMap<String, String>();
+ for (String dataDirectory : dataDirectories)
+ {
+ try
+ {
+ Path p = Path.of(dataDirectory);
+ FileStore fs = Files.getFileStore(p);
+
+ String blockDirectory = fs.name();
+ if(StringUtils.isNotEmpty(blockDirectory))
+ {
+ blockDevices.put(blockDirectory, dataDirectory);
+ }
+ }
+ catch (IOException e)
+ {
+ logger.warn("IO exception while reading file {}.", dataDirectory, e);
+ }
+ }
+ for (Map.Entry<String, String> entry: blockDevices.entrySet())
+ {
+ String blockDeviceDirectory = entry.getKey();
+ String dataDirectory = entry.getValue();
+ try
+ {
+
+ String readAheadKBPath = StartupChecks.getReadAheadKBPath(blockDeviceDirectory);
+
+ final BufferedReader bufferedReader = Files.newBufferedReader(Path.of(readAheadKBPath));
+ final String data = bufferedReader.readLine();
+ if (data != null)
+ {
+ try
+ {
+ Integer readAheadKbSetting = Integer.parseInt(data);
+
+ if (readAheadKbSetting > MAX_RECOMMENDED_READ_AHEAD_KB_SETTING)
+ {
+ logger.warn("Detected high 'read_ahead_kb' setting for device {} " +
+ "of data directory.{} It is Recommended to set this value to 8KB " +
Review comment:
Please fix message
##########
File path: src/java/org/apache/cassandra/service/StartupChecks.java
##########
@@ -285,6 +289,77 @@ public void execute()
}
};
+ public static final StartupCheck checkReadAheadKbSetting = new StartupCheck()
+ {
+ // This value is in KB.
+ private static final long MAX_RECOMMENDED_READ_AHEAD_KB_SETTING = 128;
+
+ @Override
+ public void execute() throws StartupException
+ {
+ if (!FBUtilities.isLinux)
+ return;
+
+ String[] dataDirectories = DatabaseDescriptor.getRawConfig().data_file_directories;
Review comment:
To improve readability and testability, maybe extract this to a different method?
Something like:
```java
Map<String, String> blockDevices = getBlockDevices(DatabaseDescriptor.getRawConfig().data_file_directories);
```
Also perhaps add a simple test with a temporary directory (see: https://www.javacodegeeks.com/2021/03/creating-temporary-files-with-junit-5.html).
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