reduce CGO calls when scanning rows

[charlievieth]

This commit improves the performance of queries by at least 15% by only collecting the information needed to convert sqlite3 values to Go values and by batching CGO calls when scanning rows (the performance improvement scales with the number of columns being scanned).

This commit adds a new coltype field to the SQLiteRows struct which stores the declared column type (either data/time or boolean) and the sqlite3 datatype. Previously, this library would fetch the string representation of each column, which is inefficient and rarely needed since the non-standard SQLiteRows.DeclTypes method is rarely called.

It also changes the benchmark suite to use an in-memory database since we do not want the file system interfering with benchmark results.

goos: darwin
goarch: arm64
pkg: github.com/mattn/go-sqlite3
cpu: Apple M1 Max
                             │ base.10.txt  │             new.10.txt              │
                             │    sec/op    │   sec/op     vs base                │
CustomFunctions-10              3.318µ ± 2%   3.115µ ± 2%   -6.10% (p=0.000 n=10)
Suite/BenchmarkExec-10          1.236µ ± 1%   1.240µ ± 2%        ~ (p=0.617 n=10)
Suite/BenchmarkQuery-10         4.004µ ± 7%   3.363µ ± 2%  -16.02% (p=0.000 n=10)
Suite/BenchmarkParams-10        4.241µ ± 1%   3.758µ ± 2%  -11.40% (p=0.000 n=10)
Suite/BenchmarkStmt-10          2.830µ ± 0%   2.378µ ± 2%  -15.97% (p=0.000 n=10)
Suite/BenchmarkRows-10          126.3µ ± 1%   101.3µ ± 1%  -19.79% (p=0.000 n=10)
Suite/BenchmarkStmtRows-10      124.9µ ± 1%   100.5µ ± 2%  -19.56% (p=0.000 n=10)
Suite/BenchmarkStmt10Cols-10   10.130µ ± 0%   7.042µ ± 1%  -30.48% (p=0.000 n=10)
geomean                         8.655µ        7.328µ       -15.33%

                             │ base.10.txt  │               new.10.txt               │
                             │     B/op     │     B/op      vs base                  │
CustomFunctions-10               568.0 ± 0%     576.0 ± 0%   +1.41% (p=0.000 n=10)
Suite/BenchmarkExec-10           128.0 ± 0%     128.0 ± 0%        ~ (p=1.000 n=10) ¹
Suite/BenchmarkQuery-10          688.0 ± 0%     648.0 ± 0%   -5.81% (p=0.000 n=10)
Suite/BenchmarkParams-10       1.078Ki ± 0%   1.031Ki ± 0%   -4.35% (p=0.000 n=10)
Suite/BenchmarkStmt-10           920.0 ± 0%     872.0 ± 0%   -5.22% (p=0.000 n=10)
Suite/BenchmarkRows-10         9.305Ki ± 0%   9.188Ki ± 0%   -1.26% (p=0.000 n=10)
Suite/BenchmarkStmtRows-10     9.289Ki ± 0%   9.164Ki ± 0%   -1.35% (p=0.000 n=10)
Suite/BenchmarkStmt10Cols-10     992.0 ± 0%     696.0 ± 0%  -29.84% (p=0.000 n=10)
geomean                        1.181Ki        1.106Ki        -6.35%
¹ all samples are equal

                             │ base.10.txt │              new.10.txt              │
                             │  allocs/op  │ allocs/op   vs base                  │
CustomFunctions-10              18.00 ± 0%   18.00 ± 0%        ~ (p=1.000 n=10) ¹
Suite/BenchmarkExec-10          7.000 ± 0%   7.000 ± 0%        ~ (p=1.000 n=10) ¹
Suite/BenchmarkQuery-10         23.00 ± 0%   23.00 ± 0%        ~ (p=1.000 n=10) ¹
Suite/BenchmarkParams-10        27.00 ± 0%   27.00 ± 0%        ~ (p=1.000 n=10) ¹
Suite/BenchmarkStmt-10          25.00 ± 0%   25.00 ± 0%        ~ (p=1.000 n=10) ¹
Suite/BenchmarkRows-10          525.0 ± 0%   519.0 ± 0%   -1.14% (p=0.000 n=10)
Suite/BenchmarkStmtRows-10      524.0 ± 0%   518.0 ± 0%   -1.15% (p=0.000 n=10)
Suite/BenchmarkStmt10Cols-10    39.00 ± 0%   19.00 ± 0%  -51.28% (p=0.000 n=10)
geomean                         46.26        42.17        -8.86%
¹ all samples are equal

[charlievieth]

~Commit https://github.com/mattn/go-sqlite3/pull/1291/commits/aa590cfa961c5cbb0bdd3b5477ca0f6b57debab2 addresses an issue with icu4c on macos that was caused by a recent change to the formula's name and alias: https://github.com/Homebrew/homebrew-core/pull/169239#issuecomment-2448643079~

Edit: this PR now includes https://github.com/mattn/go-sqlite3/pull/1294 since it fixes the CIFuzz and macOS tests.

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Codecov Report

Attention: Patch coverage is 78.94737% with 4 lines in your changes missing coverage. Please review.

Project coverage is 47.14%. Comparing base (18cdded) to head (fd9d096). Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
sqlite3.go	78.94%	2 Missing and 2 partials :warning:

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1291      +/-   ##
==========================================
- Coverage   47.16%   47.14%   -0.02%     
==========================================
  Files          12       12              
  Lines        1533     1542       +9     
==========================================
+ Hits          723      727       +4     
- Misses        669      672       +3     
- Partials      141      143       +2     

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[charlievieth]

Note: this PR includes https://github.com/mattn/go-sqlite3/pull/1294 since it fixes the CIFuzz and macOS tests.

[charlievieth]

@mattn or @rittneje would either of you have some spare cycles to review this PR?

[charlievieth]

@rittneje any chance you could take another look at this PR? I created it because I have a project that needs these performance gains and would like to get it off my fork.