Reduce precompilation work in the function Buffer

[ronisbr]

Hi!

I managed to reduce the precompilation work in Julia 1.9 by just rewriting the function that creates a Buffer. Unfortunately, I have no ideia if those actions have performance consequences in other scenarios since I only have access to one MSSQL server (I cannot install docker at the moment here). For my use case, there was no measurable performance degradation when fetching data, but the time to fetch the first package was greatly reduced.

Here is the timing without the modifications in Julia 1.9:

julia> @time using ODBC
  0.129348 seconds (161.98 k allocations: 12.275 MiB, 9.80% compilation time)

...

julia> function test()
       DBInterface.execute(conn, "SELECT * FROM SYSOBJECTS WHERE xtype = 'U'")
       return nothing
       end
test (generic function with 1 method)

julia> t₀ = time(); test(); t₁ = time(); println(t₁ - t₀)
49.72623920440674

Hence, it takes 50s to retrieve all the tables in the MSSQL server. The second time is way faster.

Here is the timing with the modifications in Julia 1.9:

@time using ODBC
  0.118692 seconds (159.37 k allocations: 12.150 MiB, 10.20% compilation time)

julia> function test()
       DBInterface.execute(conn, "SELECT * FROM SYSOBJECTS WHERE xtype = 'U'")
       return nothing
       end
test (generic function with 1 method)

julia> t₀ = time(); test(); t₁ = time(); println(t₁ - t₀)
7.495282888412476

Note: I could reduce even further the time to fetch the first package here using precompilation statements. However, it did not provide useful gains, because the time to load the package went from 0.11s to more than 5s.

Closes #371

[ronisbr]

I really have no ideia why the tests are failing. The function:

Buffer(ctype::API.SQLSMALLINT, columnsize, rows, nullable)

provides the same answer before and after modifications for all possible inputs.

[ronisbr]

I triggered the tests in my fork without the modifications in this PR and they are also failing. Hence, it is not be related to this PR.

[ronisbr]

Bump!

[ronisbr]

Bump v2 :)

[ronisbr]

We do not need this anymore apparently. I tested in Julia v1.10-RC1 and this time was reduced to 0.7s!