Re: FreeTDS port to VMS V9.x on x86?

On 6/25/2025 8:15 AM, Craig A. Berry wrote:

On 6/24/25 7:38 PM, Arne Vajhøj wrote:

On 6/24/2025 12:25 PM, Arne Vajhøj wrote:

I don't like the #elif HAVE_VSNPRINTF code in tds_vasprintf.
>
:-)
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The algorithm is basically to try vsnprintf with buffers
increasing in size 512, 1024, 1536, ... until there is space.
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That is very inefficient compared to just use the return value.
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And since it does not use va_copy, then only the first call to
vsnprintf will work.

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Even if va_copy was called and we ignore the option of
using vsnprintf return value, then +512 is not good
compared to *2. +512 with a 1 GB CLOB value would mean
2 million calls to vsnprintf.
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(I have not checked if TDS actually allow that long
statements, but +512 is a problem)

 TDS packet length is negotiated but must be between 512 and 32,767 bytes:
 https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-tds/ c1cddd03-b448-470a-946a-9b1b908f27a7
 And vasprintf appears to be used in FreeTDS only for query strings and
commands, not for data.

dbfcmd (which calls vasprintf) are for SQL statements in general.
SELECT and DELETE statements are not likely to be really long.
But INSERT and UPDATE statements does contain data and can
therefore be very long.
I tried using dbfcmd to insert 100 KB, 200 KB and 400 KB values.
They all succeeded (very slow but I don't know if that is the library
or something in my setup). So somewhere it must be able to chunk up such
a long SQL statement into multiple TDS packets.

You aren't wrong, but improving the vasprintf implementation isn't my
highest priority;

There are 8 billion people on this planet. It is not your
responsibility.

                  feel free to take a crack at it and submit a PR.  To
work against current sources, you either need to use autoconf with a git
checkout or get a nightly snapshot from <https://www.freetds.org>.

I may take a look.
Submitting a PR may be a problem. I have never had a personal
Github account and I suspect that my work Github account has
been deactivated. But I will worry about that when/if I have
a good fix.
Arne