Upload to HDFS stops with warning "Slow ReadProcessor read" - hadoop

When I try to upload files that are about 20 GB into HDFS they usually upload till about 12-14 GB then they stop uploading and I get a bunch of these warnings through command line
"INFO hdfs.DataStreamer: Slow ReadProcessor read fields for block BP-222805046-10.66.4.100-1587360338928:blk_1073743783_2960 took 62414ms (threshold=30000ms); ack: seqno: 226662 reply: SUCCESS downstreamAckTimeNanos: 0 flag: 0, targets:"
However, if I try to upload the files like 5-6 times, they sometimes work after the 4th or 5th attempt. I believe if I alter some data node storage settings I can achieve consistent uploads without issues but I don't know what parameters to modify in the hadoop configurations. Thanks!
Edit: This happens when I put the file into HDFS through python program which uses a subprocess call to put the file in. However, even if I directly call it from command line I still run into the same issue.

Related

Import file failed to greenplum because of one line of data on navicate

When importing a file into Greenplum,one lines fails,and the whole file is not imported successfully.Is there a way can skip the wrong line and import other data into Greenplum successfully?
Here are my SQL execution and error messages:
copy cjh_test from '/gp_wkspace/outputs/base_tables/error_data_test.csv' using delimiters ',';
ERROR: invalid input syntax for integer: "FE00F760B39BD3756BCFF30000000600"
CONTEXT: COPY cjh_test, line 81, column local_city: "FE00F760B39BD3756BCFF30000000600"
Greenplum has an extension to the COPY command that lets you log errors and set up a certain amount of errors that can occur that won't stop the load. Here is an example from the documentation for the COPY command:
COPY sales FROM '/home/usr1/sql/sales_data' LOG ERRORS
SEGMENT REJECT LIMIT 10 ROWS;
That tells COPY that 10 bad rows can be ignored without stopping the load. The reject limit can be # of rows or a percentage of the load file. You can check the full syntax in psql with: \h copy
If you are loading a very large file into Greenplum, I would suggest looking at gpload or gpfdist (which also support the segment reject limit syntax). COPY is single threaded through the master server where gpload/gpfdist load the data in parallel to all segments. COPY will be faster for smaller load files and the others will be faster for millions of rows in a load file(s).

Mainframe pkunzip generates PEX013W Record(s) being truncated to lrecl=

I'm sending binary .gz files from Linux to z/OS via ftps. The file transfers seem to be fine, but when the mainframe folks pkunzip the file, they get a warning:
PEX013W Record(s) being truncated to lrecl= 996. Record# 1 is 1000 bytes.
Currently I’m sending the site commands:
SITE TRAIL
200 SITE command was accepted
SITE CYLINDERS PRIMARY=50 SECONDARY=50
200 SITE command was accepted
SITE RECFM=VB LRECL=1000 BLKSIZE=32000
200 SITE command was accepted
SITE CONDDISP=delete
200 SITE command was accepted
TYPE I
200 Representation type is Image
...
250 Transfer completed successfully.
QUIT
221 Quit command received. Goodbye.
They could read the file after the pkunzip, but having a warning is not a good thing.
Output from pkunzip:
SDSF OUTPUT DISPLAY RMD0063A JOB22093 DSID 103 LINE 25 COLUMNS 02- 81
COMMAND INPUT ===> SCROLL ===> CSR
PCM123I Authorized services are unavailable.
PAM030I INPUT Archive opened: TEST.FTP.SOA5021.GZ
PAM560I ARCHIVE FASTSEEK processing is disabled.
PDA000I DDNAME=SYS00001,DISP_STATUS=MOD,DISP_NORMAL=CATALOG,DISP_ABNORMAL=
PDA000I SPACE_TYPE=TRK,SPACE_TYPE=CYL,SPACE_TYPE=BLK
PDA000I SPACE_PRIMARY=4194304,SPACE_DIRBLKS=5767182,INFO_ALCFMT=00
PDA000I VOLUMES=DPPT71,INFO_CNTL=,INFO_STORCLASS=,INFO_MGMTCLASS=
PDA000I INFO_DATACLASS=,INFO_VSAMRECORG=00,INFO_VSAMKEYOFF=0
PDA000I INFO_COPYDD=,INFO_COPYMDL=,INFO_AVGRECU=00,INFO_DSTYPE=00
PEX013W Record(s) being truncated to lrecl= 996. Record# 1 is 1000 bytes.
PEX002I TEST.FTP.SOA5021
PEX003I Extracted to TEST.FTP.SOA5021I.TXT
PAM140I FILES: EXTRACTED EXCLUDED BYPASSED IN ERROR
PAM140I 1 0 0 0
PMT002I PKUNZIP processing complete. RC=00000004 4(Dec) Start: 12:59:48.86 End
Is there a better set of site commands to transfer a .gz file from Linux to z/OS to avoid this error?
**** Update ****
Using SaggingRufus's answer below, it turns out it doesn't much matter how you send the .gz file, as long as it's binary. His suggestion pointed us to the parameters sent to the pkunzip for the output file, which was VB and was truncating 4 bytes off the record.
Because it is a variable block file, there are 4 bytes allocated to the record attributes. Allocate the file with an LRECL of 1004 and it will be fine.
Rather than generating a .zip file, perhaps generate a .tar.gz file and transfer it to z/OS UNIX? Tar is shipped with z/OS by default, and Rocket Software provides a port of gzip that is optimized for z/OS.

what is the file ORA_DUMMY_FILE.f in oracle?

oracle version: 12.2.0.1
As you know, these are then unix processes for the parallel servers in oracle:
ora_p000_ora12c
ora_p001_ora12c
....
ora_p???_ora12c
They can be seen also with the view: gv$px_process.
The spid for each parallel server can be obtained from there.
Then I look for the open files associated with te parallel server here:
ls -l /proc/<spid>/fd
And I'm obtaining around 500-10000 file descriptors for several parallel servers equal to this one:
991 -> /u01/app/oracle/admin/ora12c/dpdump/676185682F2D4EA0E0530100007FFF5E/ORA_DUMMY_FILE.f (deleted)
I've deleted them using:(actually I've create a small script for doing it because there are thousands of them)
gdb -p <spid>
gdb> p close(<fd_id>)
But after some hours the file descriptors start being created again (hundreds every day)
If they are not deleted then eventually the linux limit is reached and any parallel query throws an error like this:
ORA-12801: error signaled in parallel query server P001
ORA-01116: error in opening database file 132
ORA-01110: data file 132: '/u02/oradata/ora12c/pdbname/tablespacenaname_ts_1.dbf'
ORA-27077: too many files open
Does anyone have any idea of how and why this file descriptors are being created, and how to avoid it?.
Edited: Added some more information that could be useful.
I've tested that when a new PDB is created a directory DATA_PUMP_DIR is created in it (select * from all_directories) that is pointing to:
/u01/app/oracle/admin/ora12c/dpdump/<xxxxxxxxxxxxx>
The linux directory is also created.
Also one file descriptor is created pointing to ORA_DUMMY_FILE.f in the new dpdump subdirectory like the ones described initially
lsof | grep "ORA_DUMMY_FILE.f (deleted)"
/u01/app/oracle/admin/ora12c/dpdump/<xxxxxxxxxxxxx>/ORA_DUMMY_FILE.f (deleted)
This may be ok, the problem I face is the continuos growing of the file descriptors pointing to ORA_DUMMY_FILE that reach the linux limits.

Strange pause when python download file from ftp

I have some code, where i check some directories on ftp server and download new files on my server. There are above 3 million files on server (zip archives). I am doing many not optimize things in this code, but all of them works fast, except part with downloading. Here is this part:
lf = open(local_filename, "wb") //here i create blank file
print ("opened")
try:
ftp.retrbinary("RETR "+name, lf.write) //here i write data
print ("wrote")
except ftplib.error_perm:
pass
lf.close() //here i close file with data
print ("closed")
my problem in the part between print ("opened") and print ("wrote"). My python console (2.7) keep silence for 10-20 second on this fase, but size of downloading files is very tiny. Its below 2-3 Kb.
Strange thing in next: when i start script from my own PC (windows 7), it works great and fast, but when i start it on windows server 2012 R2 (VDS), i got this sadly pause. Guys, i need your help. What should i do for configuration my server and fast downloading?
i got the answer. just need to run next command:
netsh int tcp set global ecncapability=disabled
and everything will be excellent!

Random corruption in file created/updated from shell script on a singular client to NFS mount

We have bash script (job wrapper) that writes to a file, launches a job, then at job completion it appends to the file information about the job. The wrapper is run on one of several thousand batch nodes, but has only cropped up with several batch machines (I believe RHEL6) accessing one NFS server, and at least one known instance of a different batch job on a different batch node using a different NFS server. In all cases, only one client host is writing to the files in question. Some jobs take hours to run, others take minutes.
In the same time period that this has occurred, there seems to be 10-50 issues out of 100,000+ jobs.
Here is what I believe to effectively be the (distilled) version of the job wrapper:
#!/bin/bash
## cwd is /nfs/path/to/jobwd
## This file is /nfs/path/to/jobwd/job_wrapper
gotEXIT()
{
## end of script, however gotEXIT is called because we trap EXIT
END="EndTime: `date`\nStatus: Ended”
echo -e "${END}" >> job_info
cat job_info | sendmail jobtracker#example.com
}
trap gotEXIT EXIT
function jobSetVar { echo "job.$1: $2" >> job_info; }
export -f jobSetVar
MSG=“${email_metadata}\n${job_metadata}”
echo -e "${MSG}\nStatus: Started" | sendmail jobtracker#example.com
echo -e "${MSG}" > job_info
## At the job’s end, the output from `time` command is the first non-corrupt data in job_info
/usr/bin/time -f "Elapsed: %e\nUser: %U\nSystem: %S" -a -o job_info job_command
## 10-360 minutes later…
RC=$?
echo -e "ExitCode: ${RC}" >> job_info
So I think there are two possibilities:
echo -e "${MSG}" > job_info
This command throws out corrupt data.
/usr/bin/time -f "Elapsed: %e\nUser: %U\nSystem: %S" -a -o job_info job_command
This corrupts the existing data, then outputs it’s data correctly.
However, some job, but not all, call jobSetVar, which doesn't end up being corrupt.
So, I dig into time.c (from GNU time 1.7) to see when the file is open. To summarize, time.c is effectively this:
FILE *outfp;
void main (int argc, char** argv) {
const char **command_line;
RESUSE res;
/* internally, getargs opens “job_info”, so outfp = fopen ("job_info", "a”) */
command_line = getargs (argc, argv);
/* run_command doesn't care about outfp */
run_command (command_line, &res);
/* internally, summarize calls fprintf and putc on outfp FILE pointer */
summarize (outfp, output_format, command_line, &res); /
fflush (outfp);
}
So, time has FILE *outfp (job_info handle) open the entire time of the job. It then writes the summary at the end of the job, and then doesn’t actually appear to close the file (not sure if this is necessary with fflush?) I've no clue if bash also has the file handle open concurrently as well.
EDIT:
A corrupted file will typically end consist of the corrupted part, followed with the non-corrupted part, which may look like this:
The corrupted section, which would occur before the non-corrupted section, is typically largely a bunch of 0x0000, with maybe some cyclic garbage mixed in:
Here's an example hexdump:
40000000 00000000 00000000 00000000
00000000 00000000 C8B450AC 772B0000
01000000 00000000 C8B450AC 772B0000
[ 361 x 0x00]
Then, at the 409th byte, it continues with the non-corrupted section:
Elapsed: 879.07
User: 0.71
System: 31.49
ExitCode: 0
EndTime: Fri Dec 6 15:29:27 PST 2013
Status: Ended
Another file looks like this:
01000000 04000000 805443FC 9D2B0000 E04144FC 9D2B0000 E04144FC 9D2B0000
[96 x 0x00]
[Repeat above 3 times ]
01000000 04000000 805443FC 9D2B0000 E04144FC 9D2B0000 E04144FC 9D2B0000
Followed by the non corrupted section:
Elapsed: 12621.27
User: 12472.32
System: 40.37
ExitCode: 0
EndTime: Thu Nov 14 08:01:14 PST 2013
Status: Ended
There are other files that have much more random corruption sections, but more than a few were cyclical similar to above.
EDIT 2: The first email, sent from the echo -e statement goes through fine. The last email is never sent due to no email metadata from corruption. So MSG isn't corrupted at that point. It's assumed that job_info probably isn't corrupt at that point either, but we haven't been able to verify that yet. This is a production system which hasn't had major code modifications and I have verified through audit that no jobs have been ran concurrently which would touch this file. The problem seems to be somewhat recent (last 2 months), but it's possible it's happened before and slipped through. This error does prevent reporting which means jobs are considered failed, so they are typically resubmitted, but one user in specific has ~9 hour jobs in which this error is particularly frustrating. I wish I could come up with more info or a way of reproducing this at will, but I was hoping somebody has maybe seen a similar problem, especially recently. I don't manage the NFS servers, but I'll try to talk to the admins to see what updates the NFS servers at the time of these issues (RHEL6 I believe) were running.
Well, the emails corresponding to the corrupt job_info files should tell you what was in MSG (which will probably be business as usual). You may want to check how NFS is being run: there's a remote possibility that you are running NFS over UDP without checksums. That could explain some corrupt data. I also hear that UDP/TCP checksums are not strong enough and the data can still end up corrupt -- maybe you are hitting such a problem (I have seen corrupt packets slipping through a network stack at least once before, and I'm quite sure some checksumming was going on). Presumably the MSG goes out as a single packet and there might be something about it that makes checksum conflicts with the garbage you see more likely. Of course it could also be an NFS bug (client or server), a server-side filesystem bug, busted piece of RAM... possibilities are almost endless here (although I see how the fact that it's always MSG that gets corrupted makes some of those quite unlikely). The problem might be related to seeking (which happens during the append). You could also have a bug somewhere else in the system, causing multiple clients to open the same job_info file, making it a jumble.
You can also try using different file for 'time' output and then merge them together with job_info at the end of script. That may help to isolate problem further.
Shell opens 'job_info' file for writing, outputs MSG and then shall close its file descriptor before launching main job. 'time' program opens same file for append as stream and I suspect the seek over NFS is not done correctly which may cause that garbage. Can't explain why, but normally this shall not happen (and is not happening). Such rare occasions may point to some race condition somewhere, can be caused by out of sequence packet delivery (due to network latency spike) or retransmits which causes duplicate data, or a bug somewhere. At first look I would suspect some bug, but that bug may be triggered by some network behavior, e.g. unusually large delay or spike of packet loss.
File access between different processes are serialized by kernel, but for additional safeguard may be worth adding some artificial delays - sleep timers between outputs for example.
Network is not transparent, especially a large one. There can be WAN optimization devices which are known to cause application issues sometimes. CIFS and NFS are good candidates for optimization over WAN with local caching of filesystem operations. Might be worth looking for recent changes with network admins..
Another thing to try, although can be difficult due to rare occurrences is capture of interesting NFS sessions via tcpdump or wireshark. In really tough cases we do simultaneous capturing on both client and server side and then compare the protocol logic to prove that network is or is not working correctly. That's a whole topic in itself, requires thorough preparation and luck but usually a last resort of desperate troubleshooting :)
It turns out this was actually another issue altogether, apparently to do with an out-of-date page being written to disk.
A bug fix was supplied to the linux-nfs implementation:
http://www.spinics.net/lists/linux-nfs/msg41357.html

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