Receiving 0 byte files :: Support Forum

Berube
Joined:: 2020-04-20
Posts:: 5

Receiving 0 byte files

2024-07-03 14:43

We have a recurring problem with a script that runs nightly; it works most of the time, but we occasionally get files with no contents. The log from last night is attached; the problem occurred three times last night.

I have noticed something unusual in the logs. When a successful transfer occurs, the log entries contain:

< 2024-07-03 01:20:06.643 150 Opening BINARY mode data connection.
. 2024-07-03 01:20:06.689 Session ID reused
. 2024-07-03 01:20:06.689 Using TLSv1.2, cipher TLSv1.2: ECDHE-RSA-AES256-GCM-SHA384, 2048 bit RSA, ECDHE-RSA-AES256-GCM-SHA384    TLSv1.2 Kx=ECDH     Au=RSA   Enc=AESGCM(256)            Mac=AEAD
. 2024-07-03 01:20:06.689 TLS connection established
. 2024-07-03 01:20:06.736 Data connection closed
< 2024-07-03 01:20:06.736 226 Transfer complete.

However, when we get a 0 byte file, the "Session ID reused" line is missing:

< 2024-07-03 01:20:06.924 150 Opening BINARY mode data connection.
< 2024-07-03 01:20:07.049 226 Transfer complete.
. 2024-07-03 01:20:07.090 Data connection closed

WinSCP_BDS.log (39.61 KB, Private file)

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Guest

2024-07-03 15:53

Martin can of course look at the log (I can't as I'm just a guest).

But, if you know that the file on the server is indeed not 0 byte, then it makes sense that WinSCP is creating a file but is unable to get bytes into it. This can be from a connection issue such as with networking equipment. However, if WinSCP creates a file before the server gets into the read file loop, and the server has an issue, WinSCP could in theory leave a 0 byte file around.

I'm not looking at the code or anything.

Session resumption involving session id has nothing to do with this.

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martin◆ Site Admin
Joined:: 2002-12-10
Posts:: 41,441
Location:: Prague, Czechia

Re: Receiving 0 byte files

2024-07-04

@Berube: Please give us a name of a file that has 0 bytes and a file that was transferred correctly (in the log).

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Berube
Joined:: 2020-04-20
Posts:: 5

Zero-length files

2024-07-05 14:42

The files with zero length were:

ym_lims_export_20240703000027.txt
ym_lims_export_20240703000029.txt
ym_lims_export_20240703000031.txt

The original files did have content on the server.

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martin◆ Site Admin

Re: Zero-length files

2024-07-06

Please increase logging level to Debug 2 and post again logs of one successful and one zero transfer.

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Berube
Joined:: 2020-04-20
Posts:: 5

More failures

2024-07-11 14:01

Attached is the log from last night's transfers with logging at debug 2. Four files failed, those with filenames ending in 31, 32, 37, & 38.

WinSCP_BDS.log (55.25 KB, Private file)

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martin◆ Site Admin

Re: Receiving 0 byte files

2024-07-12

I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

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Receiving 0 byte files