samueldlightfoot commented on code in PR #4606:
URL: https://github.com/apache/cassandra/pull/4606#discussion_r2818185718
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src/java/org/apache/cassandra/io/sstable/format/SSTableReader.java:
##########
@@ -1417,44 +1419,60 @@ public StatsMetadata getSSTableMetadata()
return sstableMetadata;
}
+ public RandomAccessReader openDataReader()
+ {
+ return openDataReaderInternal(null, null, false);
+ }
+
public RandomAccessReader openDataReader(RateLimiter limiter)
{
assert limiter != null;
- return dfile.createReader(limiter);
+ return openDataReaderInternal(null, limiter, false);
}
- public RandomAccessReader openDataReader()
+ public RandomAccessReader openDataReader(DiskAccessMode diskAccessMode)
{
- return dfile.createReader();
+ return openDataReaderInternal(diskAccessMode, null, false);
}
public RandomAccessReader openDataReaderForScan()
{
- return openDataReaderForScan(dfile.diskAccessMode());
+ return openDataReaderInternal(null, null, true);
}
public RandomAccessReader openDataReaderForScan(DiskAccessMode
diskAccessMode)
{
- boolean isSameDiskAccessMode = diskAccessMode ==
dfile.diskAccessMode();
- boolean isDirectIONotSupported = diskAccessMode ==
DiskAccessMode.direct && !dfile.supportsDirectIO();
+ return openDataReaderInternal(diskAccessMode, null, true);
+ }
- if (isSameDiskAccessMode || isDirectIONotSupported)
- return dfile.createReaderForScan(OnReaderClose.RETAIN_FILE_OPEN);
+ private RandomAccessReader openDataReaderInternal(@Nullable DiskAccessMode
diskAccessMode,
+ @Nullable RateLimiter
limiter,
+ boolean forScan)
+ {
+ if (canReuseDfile(diskAccessMode))
+ return dfile.createReader(limiter, forScan,
OnReaderClose.RETAIN_FILE_OPEN);
- FileHandle dataFile = dfile.toBuilder()
- .withDiskAccessMode(diskAccessMode)
- .complete();
+ FileHandle handle = dfile.toBuilder()
+ .withDiskAccessMode(diskAccessMode)
+ .complete();
try
{
- return dataFile.createReaderForScan(OnReaderClose.CLOSE_FILE);
+ return handle.createReader(limiter, forScan,
OnReaderClose.CLOSE_FILE);
}
catch (Throwable t)
{
- dataFile.close();
+ handle.close();
throw t;
}
}
+ private boolean canReuseDfile(@Nullable DiskAccessMode diskAccessMode)
+ {
+ return diskAccessMode == null
+ || diskAccessMode == dfile.diskAccessMode()
+ || (diskAccessMode == DiskAccessMode.direct &&
!dfile.supportsDirectIO());
Review Comment:
We fail on start-up if any of the data file directories do not support
direct I/O.
The only case FileHandle::supportsDirectIO would return false is when an
SSTable is uncompressed as we have only implemented support for the compressed
case, which may be deemed as noise if we log for. Curious on your thoughts.
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