Possible memory leak with enumerated table dump?

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1

https://learninghub.kx.com/forums/topic/possible-memory-leak-with-enumerated-table-dump

I have the following code fragment:

E:test>q 
KDB+ 3.6 2019.04.02 Copyright (C) 1993-2019 Kx Systems w32/ 8()core 4095MB xxxxxxxx xxxxxxxx xxx.xxx.xxx.xxx NONEXPIRE 
Welcome to kdb+ 32bit edition For support please see http://groups.google.com/d/forum/personal-kdbplus Tutorials can be found at http://code.kx.com To exit, type \ To remove this startup msg, edit q.q 
q)Syms:([A:`$/:"c"$(`int$"A")+til 26] NS:til 26) 
q)T:{ ([] A:`Syms$upper x?`1; B:-1+x?2.; C:x?1000) }; 
q)(persist:`:T.dat) set T 10000; 
q).Q.w[] 
used| 304208 
heap| 67108864 
peak| 67108864 
wmax| 0 
mmap| 0 
mphy| 4294967295 
syms| 668 
symw| 24354 

q)get persist 
A B         C 
----------------- 
L 0.1561184 314 .. 

q).Q.w[] 
used| 370736 
heap| 67108864 
peak| 67108864 
wmax| 0 
mmap| 0 
mphy| 4294967295 
syms| 668 
symw| 24354 

q)do[1000; get persist ]; 
q).Q.w[] 
used| 65906736 
heap| 134217728 
peak| 134217728 
wmax| 0 
mmap| 0 
mphy| 4294967295 
syms| 668 
symw| 24354 

q).Q.gc[] 
0

As seen from above, the “used” space as reported by Q.w[] keeps increasing every single time :T.dat file was read.

Is this a sign of a memory leak somewhere caused by the enumerated column A in T.dat?

2

I tested this in 3.6 2019.04.02 could reproduce it.

The issue is not present in 3.6 2020.05.04.

Release notes of fix:

2019.05.24 FIX reading enums in log format could leak memory. e.g.

q)h:hopen`:a set ();
h enlist(`u;`sym?`a`b`c);
hclose h;
do[5;get`:a;0N!.Q.w[]`used]

 

3

Thanks for pointing this out. 2020.05.04 seems good. But I don’t seem to be able to find a 32-bit q for this version. (My test environment, unfortunately, depends on a couple of 32-bit DLLs. So I had to find a 32-bit q to use.) Any luck that I can find a 32-bit build of 2020.05.04 (or newer) anywhere?