[
https://issues.apache.org/jira/browse/HDDS-1496?focusedWorklogId=255416&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-255416
]
ASF GitHub Bot logged work on HDDS-1496:
----------------------------------------
Author: ASF GitHub Bot
Created on: 06/Jun/19 20:40
Start Date: 06/Jun/19 20:40
Worklog Time Spent: 10m
Work Description: hanishakoneru commented on pull request #804:
HDDS-1496. Support partial chunk reads and checksum verification
URL: https://github.com/apache/hadoop/pull/804#discussion_r291362428
##########
File path:
hadoop-ozone/client/src/main/java/org/apache/hadoop/ozone/client/io/KeyInputStream.java
##########
@@ -146,22 +160,34 @@ public synchronized int read(byte[] b, int off, int len)
throws IOException {
// this case.
throw new IOException(String.format(
"Inconsistent read for blockID=%s length=%d numBytesRead=%d",
- current.blockInputStream.getBlockID(), current.length,
- numBytesRead));
+ current.getBlockID(), current.getLength(), numBytesRead));
}
totalReadLen += numBytesRead;
off += numBytesRead;
len -= numBytesRead;
if (current.getRemaining() <= 0 &&
- ((currentStreamIndex + 1) < streamEntries.size())) {
- currentStreamIndex += 1;
+ ((blockIndex + 1) < blockStreams.size())) {
+ blockIndex += 1;
}
}
return totalReadLen;
}
+ /**
+ * Seeks the KeyInputStream to the specified position. This involves 2 steps:
+ * 1. Updating the blockIndex to the blockStream corresponding to the
+ * seeked position.
+ * 2. Seeking the corresponding blockStream to the adjusted position.
+ *
+ * For example, let’s say the block size is 200 bytes and block[0] stores
+ * data from indices 0 - 199, block[1] from indices 200 - 399 and so on.
+ * Let’s say we seek to position 240. In the first step, the blockIndex
+ * would be updated to 1 as indices 200 - 399 reside in blockStream[1]. In
+ * the second step, the blockStream[1] would be seeked to position 40 (=
+ * 240 - blockOffset[1] (= 200)).
+ */
@Override
- public void seek(long pos) throws IOException {
+ public synchronized void seek(long pos) throws IOException {
checkNotClosed();
Review comment:
done
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Issue Time Tracking
-------------------
Worklog Id: (was: 255416)
Time Spent: 9h (was: 8h 50m)
> Support partial chunk reads and checksum verification
> -----------------------------------------------------
>
> Key: HDDS-1496
> URL: https://issues.apache.org/jira/browse/HDDS-1496
> Project: Hadoop Distributed Data Store
> Issue Type: Improvement
> Reporter: Hanisha Koneru
> Assignee: Hanisha Koneru
> Priority: Major
> Labels: pull-request-available
> Time Spent: 9h
> Remaining Estimate: 0h
>
> BlockInputStream#readChunkFromContainer() reads the whole chunk from disk
> even if we need to read only a part of the chunk.
> This Jira aims to improve readChunkFromContainer so that only that part of
> the chunk file is read which is needed by client plus the part of chunk file
> which is required to verify the checksum.
> For example, lets say the client is reading from index 120 to 450 in the
> chunk. And let's say checksum is stored for every 100 bytes in the chunk i.e.
> the first checksum is for bytes from index 0 to 99, the next for bytes from
> index 100 to 199 and so on. To verify bytes from 120 to 450, we would need to
> read from bytes 100 to 499 so that checksum verification can be done.
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