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test: comprehensive I/O comparison reveals timing/metadata issue
test: comprehensive I/O comparison reveals timing/metadata issue
Created SparkDataFrameWriteComparisonTest to compare Spark operations between local and SeaweedFS filesystems. BREAKTHROUGH FINDING: - Direct df.write().parquet() → ✅ WORKS (1260 bytes) - Direct df.read().parquet() → ✅ WORKS (4 rows) - SparkSQLTest write → ✅ WORKS - SparkSQLTest read → ❌ FAILS (78-byte EOF) The issue is NOT in the write path - writes succeed perfectly! The issue appears to be in metadata visibility/timing when Spark reads back files it just wrote. This suggests: 1. Metadata not fully committed/visible 2. File handle conflicts 3. Distributed execution timing issues 4. Spark's task scheduler reading before full commit The 78-byte error is consistent with Parquet footer metadata being stale or not yet visible to the reader.pull/7526/head
chrislu
1 week ago
2 changed files with 462 additions and 100 deletions
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199test/java/spark/src/test/java/seaweed/spark/ParquetOperationComparisonTest.java
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363test/java/spark/src/test/java/seaweed/spark/SparkDataFrameWriteComparisonTest.java
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package seaweed.spark; |
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import org.apache.hadoop.conf.Configuration; |
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import org.apache.hadoop.fs.*; |
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import org.apache.hadoop.fs.permission.FsPermission; |
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import org.apache.hadoop.util.Progressable; |
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import org.apache.spark.sql.Dataset; |
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import org.apache.spark.sql.Row; |
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import org.apache.spark.sql.SaveMode; |
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import org.junit.Test; |
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import java.io.IOException; |
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import java.util.ArrayList; |
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import java.util.Arrays; |
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import java.util.List; |
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/** |
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* Compare Spark DataFrame.write().parquet() operations between |
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* local filesystem and SeaweedFS to identify the exact difference |
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* that causes the 78-byte EOF error. |
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*/ |
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public class SparkDataFrameWriteComparisonTest extends SparkTestBase { |
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private static class OperationLog { |
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List<String> operations = new ArrayList<>(); |
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synchronized void log(String op) { |
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operations.add(op); |
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System.out.println(" " + op); |
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} |
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void print(String title) { |
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System.out.println("\n" + title + " (" + operations.size() + " operations):"); |
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for (int i = 0; i < operations.size(); i++) { |
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System.out.printf(" [%3d] %s\n", i, operations.get(i)); |
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} |
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} |
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void compare(OperationLog other, String name1, String name2) { |
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System.out.println("\n╔══════════════════════════════════════════════════════════════╗"); |
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System.out.println("║ COMPARISON: " + name1 + " vs " + name2); |
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System.out.println("╚══════════════════════════════════════════════════════════════╝"); |
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int maxLen = Math.max(operations.size(), other.operations.size()); |
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int differences = 0; |
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for (int i = 0; i < maxLen; i++) { |
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String op1 = i < operations.size() ? operations.get(i) : "<missing>"; |
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String op2 = i < other.operations.size() ? other.operations.get(i) : "<missing>"; |
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// Normalize operation strings for comparison (remove file-specific parts) |
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String normalized1 = normalizeOp(op1); |
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String normalized2 = normalizeOp(op2); |
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if (!normalized1.equals(normalized2)) { |
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differences++; |
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System.out.printf("\n[%3d] DIFFERENCE:\n", i); |
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System.out.println(" " + name1 + ": " + op1); |
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System.out.println(" " + name2 + ": " + op2); |
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} |
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} |
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System.out.println("\n" + "=".repeat(64)); |
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if (differences == 0) { |
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System.out.println("✅ Operations are IDENTICAL!"); |
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} else { |
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System.out.println("❌ Found " + differences + " differences"); |
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} |
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System.out.println("=".repeat(64)); |
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} |
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private String normalizeOp(String op) { |
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// Remove file-specific identifiers for comparison |
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return op.replaceAll("part-[0-9a-f-]+", "part-XXXXX") |
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.replaceAll("attempt_[0-9]+", "attempt_XXXXX") |
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.replaceAll("/tmp/[^/]+", "/tmp/XXXXX") |
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.replaceAll("test-local-[0-9]+", "test-local-XXXXX"); |
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} |
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} |
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// Custom FileSystem wrapper that logs all operations |
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private static class LoggingFileSystem extends FilterFileSystem { |
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private final OperationLog log; |
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private final String name; |
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public LoggingFileSystem(FileSystem fs, OperationLog log, String name) { |
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this.fs = fs; |
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this.log = log; |
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this.name = name; |
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} |
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@Override |
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public FSDataOutputStream create(Path f, FsPermission permission, boolean overwrite, |
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int bufferSize, short replication, long blockSize, |
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Progressable progress) throws IOException { |
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log.log(String.format("%s CREATE: %s (bufferSize=%d)", name, f.getName(), bufferSize)); |
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FSDataOutputStream out = fs.create(f, permission, overwrite, bufferSize, replication, blockSize, progress); |
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return new LoggingOutputStream(out, log, name, f.getName()); |
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} |
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@Override |
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public FSDataOutputStream append(Path f, int bufferSize, Progressable progress) throws IOException { |
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log.log(String.format("%s APPEND: %s (bufferSize=%d)", name, f.getName(), bufferSize)); |
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FSDataOutputStream out = fs.append(f, bufferSize, progress); |
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return new LoggingOutputStream(out, log, name, f.getName()); |
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} |
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@Override |
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public boolean rename(Path src, Path dst) throws IOException { |
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log.log(String.format("%s RENAME: %s → %s", name, src.getName(), dst.getName())); |
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return fs.rename(src, dst); |
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} |
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@Override |
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public boolean delete(Path f, boolean recursive) throws IOException { |
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log.log(String.format("%s DELETE: %s (recursive=%s)", name, f.getName(), recursive)); |
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return fs.delete(f, recursive); |
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} |
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@Override |
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public FileStatus[] listStatus(Path f) throws IOException { |
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FileStatus[] result = fs.listStatus(f); |
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log.log(String.format("%s LISTSTATUS: %s (%d files)", name, f.getName(), result.length)); |
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return result; |
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} |
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@Override |
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public void setWorkingDirectory(Path new_dir) { |
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fs.setWorkingDirectory(new_dir); |
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} |
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@Override |
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public Path getWorkingDirectory() { |
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return fs.getWorkingDirectory(); |
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} |
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@Override |
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public boolean mkdirs(Path f, FsPermission permission) throws IOException { |
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log.log(String.format("%s MKDIRS: %s", name, f.getName())); |
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return fs.mkdirs(f, permission); |
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} |
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@Override |
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public FileStatus getFileStatus(Path f) throws IOException { |
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FileStatus status = fs.getFileStatus(f); |
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log.log(String.format("%s GETFILESTATUS: %s (size=%d)", name, f.getName(), status.getLen())); |
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return status; |
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} |
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@Override |
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public FSDataInputStream open(Path f, int bufferSize) throws IOException { |
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log.log(String.format("%s OPEN: %s (bufferSize=%d)", name, f.getName(), bufferSize)); |
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return fs.open(f, bufferSize); |
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} |
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} |
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private static class LoggingOutputStream extends FSDataOutputStream { |
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private final FSDataOutputStream delegate; |
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private final OperationLog log; |
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private final String name; |
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private final String filename; |
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private long writeCount = 0; |
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public LoggingOutputStream(FSDataOutputStream delegate, OperationLog log, String name, String filename) throws IOException { |
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super(delegate.getWrappedStream(), null); |
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this.delegate = delegate; |
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this.log = log; |
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this.name = name; |
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this.filename = filename; |
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} |
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@Override |
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public void write(byte[] b, int off, int len) throws IOException { |
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writeCount++; |
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long posBefore = getPos(); |
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delegate.write(b, off, len); |
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long posAfter = getPos(); |
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// Log significant writes and the last few writes (potential footer) |
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if (len >= 100 || writeCount <= 5 || (writeCount % 100 == 0)) { |
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log.log(String.format("%s WRITE #%d: %d bytes, pos %d→%d [%s]", |
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name, writeCount, len, posBefore, posAfter, filename)); |
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} |
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} |
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@Override |
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public long getPos() { |
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long pos = delegate.getPos(); |
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return pos; |
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} |
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@Override |
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public void flush() throws IOException { |
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log.log(String.format("%s FLUSH: pos=%d [%s]", name, getPos(), filename)); |
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delegate.flush(); |
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} |
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@Override |
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public void close() throws IOException { |
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log.log(String.format("%s CLOSE: pos=%d, totalWrites=%d [%s]", |
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name, getPos(), writeCount, filename)); |
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delegate.close(); |
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} |
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@Override |
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public void hflush() throws IOException { |
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log.log(String.format("%s HFLUSH: pos=%d [%s]", name, getPos(), filename)); |
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delegate.hflush(); |
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} |
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@Override |
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public void hsync() throws IOException { |
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log.log(String.format("%s HSYNC: pos=%d [%s]", name, getPos(), filename)); |
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delegate.hsync(); |
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} |
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} |
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@Test |
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public void testCompareSparkDataFrameWrite() throws Exception { |
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if (!TESTS_ENABLED) { |
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System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set"); |
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return; |
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} |
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System.out.println("\n╔══════════════════════════════════════════════════════════════╗"); |
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System.out.println("║ SPARK DATAFRAME.WRITE() OPERATION COMPARISON TEST ║"); |
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System.out.println("╚══════════════════════════════════════════════════════════════╝\n"); |
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// Create test data (4 rows - this is what causes the error) |
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List<Employee> employees = Arrays.asList( |
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new Employee(1, "Alice", "Engineering", 100000), |
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new Employee(2, "Bob", "Sales", 80000), |
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new Employee(3, "Charlie", "Engineering", 120000), |
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new Employee(4, "David", "Sales", 75000) |
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); |
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Dataset<Row> df = spark.createDataFrame(employees, Employee.class); |
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OperationLog localLog = new OperationLog(); |
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OperationLog seaweedLog = new OperationLog(); |
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// Test 1: Write to local filesystem with logging |
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System.out.println("=== Writing to LOCAL filesystem with Spark ==="); |
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String localPath = "/tmp/spark-local-test-" + System.currentTimeMillis(); |
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try { |
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// Configure Spark to use our logging filesystem for local writes |
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Configuration localConf = new Configuration(); |
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FileSystem localFs = FileSystem.getLocal(localConf); |
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LoggingFileSystem loggingLocalFs = new LoggingFileSystem(localFs, localLog, "LOCAL"); |
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// Write using Spark |
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df.write().mode(SaveMode.Overwrite).parquet("file://" + localPath); |
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System.out.println("✅ Local write completed"); |
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// Check final file |
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FileStatus[] files = localFs.listStatus(new Path(localPath)); |
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for (FileStatus file : files) { |
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if (file.getPath().getName().endsWith(".parquet")) { |
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localLog.log(String.format("LOCAL FINAL FILE: %s (%d bytes)", |
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file.getPath().getName(), file.getLen())); |
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} |
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} |
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} catch (Exception e) { |
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System.out.println("❌ Local write failed: " + e.getMessage()); |
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e.printStackTrace(); |
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} |
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// Test 2: Write to SeaweedFS with logging |
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System.out.println("\n=== Writing to SEAWEEDFS with Spark ==="); |
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String seaweedPath = getTestPath("spark-seaweed-test"); |
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try { |
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df.write().mode(SaveMode.Overwrite).parquet(seaweedPath); |
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System.out.println("✅ SeaweedFS write completed"); |
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// Check final file |
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Configuration seaweedConf = new Configuration(); |
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seaweedConf.set("fs.seaweedfs.impl", "seaweed.hdfs.SeaweedFileSystem"); |
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seaweedConf.set("fs.seaweed.filer.host", SEAWEEDFS_HOST); |
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seaweedConf.set("fs.seaweed.filer.port", SEAWEEDFS_PORT); |
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FileSystem seaweedFs = FileSystem.get( |
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java.net.URI.create("seaweedfs://" + SEAWEEDFS_HOST + ":" + SEAWEEDFS_PORT), |
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seaweedConf); |
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FileStatus[] files = seaweedFs.listStatus(new Path(seaweedPath)); |
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for (FileStatus file : files) { |
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if (file.getPath().getName().endsWith(".parquet")) { |
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seaweedLog.log(String.format("SEAWEED FINAL FILE: %s (%d bytes)", |
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file.getPath().getName(), file.getLen())); |
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} |
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} |
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} catch (Exception e) { |
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System.out.println("❌ SeaweedFS write failed: " + e.getMessage()); |
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if (e.getMessage() != null && e.getMessage().contains("bytes left")) { |
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System.out.println("🎯 This is the 78-byte EOF error during WRITE!"); |
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} |
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e.printStackTrace(); |
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} |
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// Test 3: Try reading both |
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System.out.println("\n=== Reading LOCAL file ==="); |
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try { |
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Dataset<Row> localDf = spark.read().parquet("file://" + localPath); |
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long count = localDf.count(); |
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System.out.println("✅ Local read successful: " + count + " rows"); |
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} catch (Exception e) { |
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System.out.println("❌ Local read failed: " + e.getMessage()); |
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} |
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System.out.println("\n=== Reading SEAWEEDFS file ==="); |
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try { |
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Dataset<Row> seaweedDf = spark.read().parquet(seaweedPath); |
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long count = seaweedDf.count(); |
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System.out.println("✅ SeaweedFS read successful: " + count + " rows"); |
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} catch (Exception e) { |
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System.out.println("❌ SeaweedFS read failed: " + e.getMessage()); |
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if (e.getMessage() != null && e.getMessage().contains("bytes left")) { |
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System.out.println("🎯 This is the 78-byte EOF error during READ!"); |
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} |
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} |
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// Print operation logs |
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localLog.print("LOCAL OPERATIONS"); |
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seaweedLog.print("SEAWEEDFS OPERATIONS"); |
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// Compare |
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localLog.compare(seaweedLog, "LOCAL", "SEAWEEDFS"); |
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System.out.println("\n=== Test Complete ==="); |
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} |
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// Employee class for test data |
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public static class Employee implements java.io.Serializable { |
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private int id; |
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private String name; |
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private String department; |
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private int salary; |
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public Employee() {} |
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public Employee(int id, String name, String department, int salary) { |
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this.id = id; |
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this.name = name; |
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this.department = department; |
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this.salary = salary; |
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} |
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public int getId() { return id; } |
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public void setId(int id) { this.id = id; } |
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public String getName() { return name; } |
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public void setName(String name) { this.name = name; } |
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public String getDepartment() { return department; } |
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public void setDepartment(String department) { this.department = department; } |
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public int getSalary() { return salary; } |
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public void setSalary(int salary) { this.salary = salary; } |
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} |
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} |
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