Set SQLITE_LIMIT_FUNCTION_ARG to SQLite's normal default.

[kentonv]

People keep legitimately running up against this limit. It's not really clear what value it is providing, so let's just match the default.

Fixes #2412

[justin-mp]

Just to add color here, according to https://www.sqlite.org/limits.html (search for "Maximum Number Of Arguments On A Function"), the default is 100 and absolute maximum is 127 because this value is sometimes stored in an unsigned char.

Sure enough, sqliteLimit.h has:

#ifndef SQLITE_MAX_FUNCTION_ARG
# define SQLITE_MAX_FUNCTION_ARG 127
#endif

I can't seem to figure out where the default of 100 is set.

[justin-mp]

nit: s/default/maximum/ ?

[kentonv]

Weird, https://www.sqlite.org/security.html says that the default is 127, not 100.

My intent was to use the default.

I guess I can try to find out what sqlite actually reports its own default as being...

[justin-mp]

Digging more: the default is 127 and https://www.sqlite.org/limits.html is buggy. Here's what my sqlite3 reports:

sqlite> .limit
              length 1000000000
          sql_length 1000000000
              column 2000
          expr_depth 1000
     compound_select 500
             vdbe_op 250000000
        function_arg 127
            attached 10
 like_pattern_length 50000
     variable_number 250000
       trigger_depth 1000
      worker_threads 0

The limits from the compile-time constants are initialized into a static const int aHardLimit[] and then that array is copied into the per-database limit in openDatabase(...):

  assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
  memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));

So it's the default and maximum.

[anonrig]

Since this might change in the future, maybe we should add a link to the existing documentation?

[anonrig]

Weird, https://www.sqlite.org/security.html says that the default is 127, not 100.

PS: https://www.sqlite.org/c3ref/create_function.html Also mentions max 127 value.

[kentonv]

OK seems like this is correct as-is, just gonna merge.

[HendrixString]

@kentonv Hi,

when is this gonna be released up stream into production ?

Unfortunately, i am hitting the upper limit of 32 (I have 36 params in json_object)