Github user sandhyasun commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/889#discussion_r94461709
--- Diff: core/sql/exp/ExpLOBaccess.cpp ---
@@ -1502,7 +1507,50 @@ Ex_Lob_Error ExLob::allocateDesc(ULng32 size, Int64
&descNum, Int64 &dataOffset,
char logBuf[4096];
lobDebugInfo("In ExLob::allocateDesc",0,__LINE__,lobTrace_);
Int32 openFlags = O_RDONLY ;
-
+ if (size == 0) //we are trying to empty this lob.
+ {
+ //rename lob datafile
+ char * saveLobDataFile = new(getLobGlobalHeap())
char[MAX_LOB_FILE_NAME_LEN+6];
+ str_sprintf(saveLobDataFile, "%s_save",lobDataFile_);
+ Int32 rc2 = hdfsRename(fs_,lobDataFile_,saveLobDataFile);
+ if (rc2 == -1)
+ {
+ lobDebugInfo("Problem renaming datafile to save data
file",0,__LINE__,lobTrace_);
+ NADELETEBASIC(saveLobDataFile,getLobGlobalHeap());
+ return LOB_DATA_FILE_WRITE_ERROR;
+ }
+ //create a new file of the same name.
+ hdfsFile fdNew = hdfsOpenFile(fs_,
lobDataFile_,O_WRONLY|O_CREAT,0,0,0);
+ if (!fdNew)
+ {
+ str_sprintf(logBuf,"Could not create/open
file:%s",lobDataFile_);
+ lobDebugInfo(logBuf,0,__LINE__,lobTrace_);
+
+ //restore previous version
+ Int32 rc2 = hdfsRename(fs_,saveLobDataFile,lobDataFile_);
+ if (rc2 == -1)
+ {
+ lobDebugInfo("Problem restoring datafile . Will need to
retry the update",0,__LINE__,lobTrace_);
+ NADELETEBASIC(saveLobDataFile,getLobGlobalHeap());
+ return LOB_DATA_FILE_WRITE_ERROR;
+ }
+ return LOB_DATA_FILE_OPEN_ERROR;
--- End diff --
its deleted below in the "else" part
else
{
//A new empty data file has been created.
// delete the saved data file
Int32 rc2 = hdfsDelete(fs_,saveLobDataFile,FALSE);//ok to
ignore error.nt32
if (rc2 == -1)
{
lobDebugInfo("Problem deleting saved datafile . Will need
to manually cleanup saved datafile",0,__LINE__,lobTrace_);
}
NADELETEBASIC(saveLobDataFile,getLobGlobalHeap());
hdfsCloseFile(fs_,fdNew);
fdNew = NULL;
}
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