Repository: mattn/go-sqlite3
Pull request #568 (2018-05-25 13:45:26)

Fix/usleep
[sqlite3.go](./sqlite3.go#L12) defines the following:

Line: 12
```go
#cgo CFLAGS: -DSQLITE_ENABLE_RTREE -DSQLITE_THREADSAFE=1 -DHAVE_USLEEP=1
```
This means `usleep` is activated even for Windows OS.

However usleep is a *nix command and not available on Windows.
When usleep is not available SQLite3 waits for 1 second.

This implementation adds the `usleep` command for Windows to increases performance.

[Full fix review](https://github.com/GJRTimmer/go-sqlite3/blob/7c89b38a2da041bb3bd4f5db59151ea430c5b1f0/sqlite3_usleep_windows.go)

BenchMark

| Key | Value |
|-----|--------|
|OS | Windows 10 Build: 17134.48 |
| CPU | Intel: 2.8 GHz |
| Cores | 4 |
| Memory | 16 GB |

BenchMark before fix.
```bash
BenchmarkExec           100000      40339 req/s
BenchmarkQuery           10000       3932 req/s
BenchmarkParams           5000       3367 req/s
BenchmarkStmt             5000       4010 req/s
BenchmarkRows                1          1 req/s
BenchmarkStmtRows         1000        447 req/s
```

BenchMark after fix.
```bash
BenchmarkExec           100000      77720 req/s
BenchmarkQuery           10000       6751 req/s
BenchmarkParams          10000       6579 req/s
BenchmarkStmt            10000       6878 req/s
BenchmarkRows                1          1 req/s
BenchmarkStmtRows         1000        632 req/s
```

This PR is based upon #563 please merge #563 before merging this.

@mattn Please remove you stale branch `add-usleep`.


Patch:
diff --git a/.travis.yml b/.travis.yml
index ac1d7e3..ba8c891 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,125 +12,79 @@ env:
   matrix:
     - GOTAGS=
     - GOTAGS=libsqlite3
-    - GOTAGS=trace
-    - GOTAGS=vtable
+    - GOTAGS="sqlite_allow_uri_authority sqlite_app_armor sqlite_foreign_keys sqlite_fts5 sqlite_icu sqlite_introspect sqlite_json sqlite_secure_delete sqlite_see sqlite_stat4 sqlite_trace sqlite_userauth"
+    - GOTAGS=sqlite_vacuum_full
+    - GOTAGS=sqlite_vacuum_incr
+    - GOTAGS=sqlite_vtable
 
 go:
-  - 1.7.x
   - 1.8.x
   - 1.9.x
   - 1.10.x
-  - master
 
 matrix:
-  allow_failures:
-    - go: master
-  exclude:
-    - os: osx
-      go: 1.7.x
   include:
-    - os: linux
-      go: 1.7.x
-      env: GOTAGS= GOOS=windows GOARCH=386
-    - os: linux
-      go: 1.7.x
-      env: GOTAGS= GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.7.x
-      env: GOTAGS=libsqlite3 GOOS=windows GOARCH=386
-    - os: linux
-      go: 1.7.x
-      env: GOTAGS=libsqlite3 GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.7.x
-      env: GOTAGS=trace GOOS=windows GOARCH=386
-    - os: linux
-      go: 1.7.x
-      env: GOTAGS=trace GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.7.x
-      env: GOTAGS=vtable GOOS=windows GOARCH=386
-    - os: linux
-      go: 1.7.x
-      env: GOTAGS=vtable GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.8.x
-      env: GOTAGS= GOOS=windows GOARCH=386
     - os: linux
       go: 1.8.x
       env: GOTAGS= GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.8.x
-      env: GOTAGS=libsqlite3 GOOS=windows GOARCH=386
     - os: linux
       go: 1.8.x
       env: GOTAGS=libsqlite3 GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.8.x
-      env: GOTAGS=trace GOOS=windows GOARCH=386
+      env: GOTAGS="sqlite_allow_uri_authority sqlite_app_armor sqlite_foreign_keys sqlite_fts5 sqlite_icu sqlite_introspect sqlite_json sqlite_secure_delete sqlite_see sqlite_stat4 sqlite_trace sqlite_userauth" GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.8.x
-      env: GOTAGS=trace GOOS=windows GOARCH=amd64
+      env: GOTAGS=sqlite_vacuum_full GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.8.x
-      env: GOTAGS=vtable GOOS=windows GOARCH=386
+      env: GOTAGS=sqlite_vacuum_incr GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.8.x
-      env: GOTAGS=vtable GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.9.x
-      env: GOTAGS= GOOS=windows GOARCH=386
+      env: GOTAGS=sqlite_vtable GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.9.x
       env: GOTAGS= GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.9.x
-      env: GOTAGS=libsqlite3 GOOS=windows GOARCH=386
     - os: linux
       go: 1.9.x
       env: GOTAGS=libsqlite3 GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.9.x
-      env: GOTAGS=trace GOOS=windows GOARCH=386
+      env: GOTAGS="sqlite_allow_uri_authority sqlite_app_armor sqlite_foreign_keys sqlite_fts5 sqlite_icu sqlite_introspect sqlite_json sqlite_secure_delete sqlite_see sqlite_stat4 sqlite_trace sqlite_userauth" GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.9.x
-      env: GOTAGS=trace GOOS=windows GOARCH=amd64
+      env: GOTAGS=sqlite_vacuum_full GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.9.x
-      env: GOTAGS=vtable GOOS=windows GOARCH=386
+      env: GOTAGS=sqlite_vacuum_incr GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.9.x
-      env: GOTAGS=vtable GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.10.x
-      env: GOTAGS= GOOS=windows GOARCH=386
+      env: GOTAGS=sqlite_vtable GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.10.x
       env: GOTAGS= GOOS=windows GOARCH=amd64
-    - os: linux
-      go: 1.10.x
-      env: GOTAGS=libsqlite3 GOOS=windows GOARCH=386
     - os: linux
       go: 1.10.x
       env: GOTAGS=libsqlite3 GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.10.x
-      env: GOTAGS=trace GOOS=windows GOARCH=386
+      env: GOTAGS="sqlite_allow_uri_authority sqlite_app_armor sqlite_foreign_keys sqlite_fts5 sqlite_icu sqlite_introspect sqlite_json sqlite_secure_delete sqlite_see sqlite_stat4 sqlite_trace sqlite_userauth" GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.10.x
-      env: GOTAGS=trace GOOS=windows GOARCH=amd64
+      env: GOTAGS=sqlite_vacuum_full GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.10.x
-      env: GOTAGS=vtable GOOS=windows GOARCH=386
+      env: GOTAGS=sqlite_vacuum_incr GOOS=windows GOARCH=amd64
     - os: linux
       go: 1.10.x
-      env: GOTAGS=vtable GOOS=windows GOARCH=amd64
+      env: GOTAGS=sqlite_vtable GOOS=windows GOARCH=amd64
 
 
 before_install:
   - |
     if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then 
       brew update
+      brew upgrade icu4c
     fi
   - |
     if [[ "${GOOS}" != "windows" ]]; then
diff --git a/README.md b/README.md
index 4870adf..6a71218 100644
--- a/README.md
+++ b/README.md
@@ -6,13 +6,19 @@ go-sqlite3
 [![Coverage Status](https://coveralls.io/repos/mattn/go-sqlite3/badge.svg?branch=master)](https://coveralls.io/r/mattn/go-sqlite3?branch=master)
 [![Go Report Card](https://goreportcard.com/badge/github.com/mattn/go-sqlite3)](https://goreportcard.com/report/github.com/mattn/go-sqlite3)
 
-Description
------------
+# Description
 
 sqlite3 driver conforming to the built-in database/sql interface
 
-Installation
-------------
+### Overview
+
+- [Installation](#installation)
+- [API Reference](#api-reference)
+- [Features](#features)
+- [FAQ](#faq)
+- [License](#license)
+
+# Installation
 
 This package can be installed with the go get command:
 
@@ -22,56 +28,80 @@ _go-sqlite3_ is *cgo* package.
 If you want to build your app using go-sqlite3, you need gcc.
 However, after you have built and installed _go-sqlite3_ with `go install github.com/mattn/go-sqlite3` (which requires gcc), you can build your app without relying on gcc in future.
 
-Documentation
--------------
+# API Reference
 
 API documentation can be found here: http://godoc.org/github.com/mattn/go-sqlite3
 
-Examples can be found under the `./_example` directory
+Examples can be found under the [examples](./_example) directory
+
+# Features
+
+This package allows additional configuration of features available within SQLite3 to be enabled or disabled by golang build constraints also known as build `tags`.
 
-FAQ
----
+[Click here for more information about build tags / constraints.](https://golang.org/pkg/go/build/#hdr-Build_Constraints)
 
-* Want to build go-sqlite3 with libsqlite3 on my linux.
+| Extension | Build Tag | Description |
+|-----------|-----------|-------------|
+| Additional Statistics | sqlite_stat4 | This option adds additional logic to the ANALYZE command and to the query planner that can help SQLite to chose a better query plan under certain situations. The ANALYZE command is enhanced to collect histogram data from all columns of every index and store that data in the sqlite_stat4 table.<br><br>The query planner will then use the histogram data to help it make better index choices. The downside of this compile-time option is that it violates the query planner stability guarantee making it more difficult to ensure consistent performance in mass-produced applications.<br><br>SQLITE_ENABLE_STAT4 is an enhancement of SQLITE_ENABLE_STAT3. STAT3 only recorded histogram data for the left-most column of each index whereas the STAT4 enhancement records histogram data from all columns of each index.<br><br>The SQLITE_ENABLE_STAT3 compile-time option is a no-op and is ignored if the SQLITE_ENABLE_STAT4 compile-time option is used |
+| Allow URI Authority | sqlite_allow_uri_authority | URI filenames normally throws an error if the authority section is not either empty or "localhost".<br><br>However, if SQLite is compiled with the SQLITE_ALLOW_URI_AUTHORITY compile-time option, then the URI is converted into a Uniform Naming Convention (UNC) filename and passed down to the underlying operating system that way |
+| App Armor | sqlite_app_armor | When defined, this C-preprocessor macro activates extra code that attempts to detect misuse of the SQLite API, such as passing in NULL pointers to required parameters or using objects after they have been destroyed. <br><br>App Armor is not available under `Windows`. |
+| Disable Load Extensions | sqlite_omit_load_extension | Loading of external extensions is enabled by default.<br><br>To disable extension loading add the build tag `sqlite_omit_load_extension`. |
+| Foreign Keys | sqlite_foreign_keys | This macro determines whether enforcement of foreign key constraints is enabled or disabled by default for new database connections.<br><br>Each database connection can always turn enforcement of foreign key constraints on and off and run-time using the foreign_keys pragma.<br><br>Enforcement of foreign key constraints is normally off by default, but if this compile-time parameter is set to 1, enforcement of foreign key constraints will be on by default | 
+| Full Auto Vacuum | sqlite_vacuum_full | Set the default auto vacuum to full |
+| Incremental Auto Vacuum | sqlite_vacuum_incr | Set the default auto vacuum to incremental |
+| Full Text Search Engine | sqlite_fts5 | When this option is defined in the amalgamation, versions 5 of the full-text search engine (fts5) is added to the build automatically |
+|  International Components for Unicode | sqlite_icu | This option causes the International Components for Unicode or "ICU" extension to SQLite to be added to the build |
+| Introspect PRAGMAS | sqlite_introspect | This option adds some extra PRAGMA statements. <ul><li>PRAGMA function_list</li><li>PRAGMA module_list</li><li>PRAGMA pragma_list</li></ul> |
+| JSON SQL Functions | sqlite_json | When this option is defined in the amalgamation, the JSON SQL functions are added to the build automatically |
+| Secure Delete | sqlite_secure_delete | This compile-time option changes the default setting of the secure_delete pragma.<br><br>When this option is not used, secure_delete defaults to off. When this option is present, secure_delete defaults to on.<br><br>The secure_delete setting causes deleted content to be overwritten with zeros. There is a small performance penalty since additional I/O must occur.<br><br>On the other hand, secure_delete can prevent fragments of sensitive information from lingering in unused parts of the database file after it has been deleted. See the documentation on the secure_delete pragma for additional information |
+| Tracing / Debug | sqlite_trace | Activate trace functions |
+
+# FAQ
+
+- Want to build go-sqlite3 with libsqlite3 on my linux.
 
     Use `go build --tags "libsqlite3 linux"`
 
-* Want to build go-sqlite3 with libsqlite3 on OS X.
+- Want to build go-sqlite3 with libsqlite3 on OS X.
 
     Install sqlite3 from homebrew: `brew install sqlite3`
 
     Use `go build --tags "libsqlite3 darwin"`
 
-* Want to build go-sqlite3 with icu extension.
+- Want to build go-sqlite3 with additional extensions / features.
+
+    Use `go build --tags "<FEATURE>"`
+
+    When using multiple build tags, all the different tags should be space delimted.
 
-   Use `go build --tags "icu"`
+    For available features / extensions see [Features](#features).
 
-   Available extensions: `json1`, `fts5`, `icu`
+    Example building multiple features: `go build --tags "icu json1 fts5 secure_delete"`
 
-* Can't build go-sqlite3 on windows 64bit.
+- Can't build go-sqlite3 on windows 64bit.
 
     > Probably, you are using go 1.0, go1.0 has a problem when it comes to compiling/linking on windows 64bit.
     > See: [#27](https://github.com/mattn/go-sqlite3/issues/27)
 
-* Getting insert error while query is opened.
+- Getting insert error while query is opened.
 
     > You can pass some arguments into the connection string, for example, a URI.
     > See: [#39](https://github.com/mattn/go-sqlite3/issues/39)
 
-* Do you want to cross compile? mingw on Linux or Mac?
+- Do you want to cross compile? mingw on Linux or Mac?
 
     > See: [#106](https://github.com/mattn/go-sqlite3/issues/106)
     > See also: http://www.limitlessfx.com/cross-compile-golang-app-for-windows-from-linux.html
 
-* Want to get time.Time with current locale
+- Want to get time.Time with current locale
 
     Use `_loc=auto` in SQLite3 filename schema like `file:foo.db?_loc=auto`.
 
-* Can I use this in multiple routines concurrently?
+- Can I use this in multiple routines concurrently?
 
     Yes for readonly. But, No for writable. See [#50](https://github.com/mattn/go-sqlite3/issues/50), [#51](https://github.com/mattn/go-sqlite3/issues/51), [#209](https://github.com/mattn/go-sqlite3/issues/209), [#274](https://github.com/mattn/go-sqlite3/issues/274).
 
-* Why is it racy if I use a `sql.Open("sqlite3", ":memory:")` database?
+- Why is it racy if I use a `sql.Open("sqlite3", ":memory:")` database?
 
     Each connection to :memory: opens a brand new in-memory sql database, so if
     the stdlib's sql engine happens to open another connection and you've only
@@ -80,8 +110,7 @@ FAQ
     connection to this string will point to the same in-memory database. See
     [#204](https://github.com/mattn/go-sqlite3/issues/204) for more info.
 
-License
--------
+# License
 
 MIT: http://mattn.mit-license.org/2012
 
@@ -91,7 +120,6 @@ The -binding suffix was added to avoid build failures under gccgo.
 
 In this repository, those files are an amalgamation of code that was copied from SQLite3. The license of that code is the same as the license of SQLite3.
 
-Author
-------
+# Author
 
 Yasuhiro Matsumoto (a.k.a mattn)
diff --git a/sqlite3_opt_allow_uri_authority.go b/sqlite3_opt_allow_uri_authority.go
new file mode 100644
index 0000000..2a5c497
--- /dev/null
+++ b/sqlite3_opt_allow_uri_authority.go
@@ -0,0 +1,13 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build sqlite_allow_uri_authority
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_ALLOW_URI_AUTHORITY
+#cgo LDFLAGS: -lm
+*/
+import "C"
diff --git a/sqlite3_opt_app_armor.go b/sqlite3_opt_app_armor.go
new file mode 100644
index 0000000..7108c5d
--- /dev/null
+++ b/sqlite3_opt_app_armor.go
@@ -0,0 +1,14 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build !windows
+// +build sqlite_app_armor
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_ENABLE_API_ARMOR
+#cgo LDFLAGS: -lm
+*/
+import "C"
diff --git a/sqlite3_opt_foreign_keys.go b/sqlite3_opt_foreign_keys.go
new file mode 100644
index 0000000..882a1cd
--- /dev/null
+++ b/sqlite3_opt_foreign_keys.go
@@ -0,0 +1,13 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build sqlite_foreign_keys
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_DEFAULT_FOREIGN_KEYS=1
+#cgo LDFLAGS: -lm
+*/
+import "C"
diff --git a/sqlite3_fts3_test.go b/sqlite3_opt_fts3_test.go
similarity index 100%
rename from sqlite3_fts3_test.go
rename to sqlite3_opt_fts3_test.go
diff --git a/sqlite3_fts5.go b/sqlite3_opt_fts5.go
similarity index 90%
rename from sqlite3_fts5.go
rename to sqlite3_opt_fts5.go
index 0e65d69..9126272 100644
--- a/sqlite3_fts5.go
+++ b/sqlite3_opt_fts5.go
@@ -2,7 +2,7 @@
 //
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
-// +build fts5
+// +build sqlite_fts5 fts5
 
 package sqlite3
 
diff --git a/sqlite3_opt_icu.go b/sqlite3_opt_icu.go
new file mode 100644
index 0000000..9bc0c61
--- /dev/null
+++ b/sqlite3_opt_icu.go
@@ -0,0 +1,15 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build sqlite_icu icu
+
+package sqlite3
+
+/*
+#cgo LDFLAGS: -licuuc -licui18n
+#cgo CFLAGS: -DSQLITE_ENABLE_ICU
+#cgo darwin CFLAGS: -I/usr/local/opt/icu4c/include
+#cgo darwin LDFLAGS: -L/usr/local/opt/icu4c/lib
+*/
+import "C"
diff --git a/sqlite3_opt_introspect.go b/sqlite3_opt_introspect.go
new file mode 100644
index 0000000..19fd3ee
--- /dev/null
+++ b/sqlite3_opt_introspect.go
@@ -0,0 +1,13 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build sqlite_introspect
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_INTROSPECTION_PRAGMAS
+#cgo LDFLAGS: -lm
+*/
+import "C"
diff --git a/sqlite3_json1.go b/sqlite3_opt_json1.go
similarity index 85%
rename from sqlite3_json1.go
rename to sqlite3_opt_json1.go
index a7b2473..993f037 100644
--- a/sqlite3_json1.go
+++ b/sqlite3_opt_json1.go
@@ -2,7 +2,7 @@
 //
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
-// +build json1
+// +build sqlite_json sqlite_json1 json1
 
 package sqlite3
 
diff --git a/sqlite3_opt_secure_delete.go b/sqlite3_opt_secure_delete.go
new file mode 100644
index 0000000..0ea5594
--- /dev/null
+++ b/sqlite3_opt_secure_delete.go
@@ -0,0 +1,13 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build sqlite_secure_delete
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_SECURE_DELETE
+#cgo LDFLAGS: -lm
+*/
+import "C"
diff --git a/sqlite3_icu.go b/sqlite3_opt_stat4.go
similarity index 72%
rename from sqlite3_icu.go
rename to sqlite3_opt_stat4.go
index e960626..706cb87 100644
--- a/sqlite3_icu.go
+++ b/sqlite3_opt_stat4.go
@@ -2,12 +2,12 @@
 //
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
-// +build icu
+// +build sqlite_stat4
 
 package sqlite3
 
 /*
-#cgo LDFLAGS: -licuuc -licui18n
-#cgo CFLAGS: -DSQLITE_ENABLE_ICU
+#cgo CFLAGS: -DSQLITE_ENABLE_STAT4
+#cgo LDFLAGS: -lm
 */
 import "C"
diff --git a/sqlite3_opt_vacuum_full.go b/sqlite3_opt_vacuum_full.go
new file mode 100644
index 0000000..7217f95
--- /dev/null
+++ b/sqlite3_opt_vacuum_full.go
@@ -0,0 +1,13 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build sqlite_vacuum_full
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_DEFAULT_AUTOVACUUM=1
+#cgo LDFLAGS: -lm
+*/
+import "C"
diff --git a/sqlite3_opt_vacuum_incr.go b/sqlite3_opt_vacuum_incr.go
new file mode 100644
index 0000000..8dccc43
--- /dev/null
+++ b/sqlite3_opt_vacuum_incr.go
@@ -0,0 +1,13 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build sqlite_vacuum_incr
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_DEFAULT_AUTOVACUUM=2
+#cgo LDFLAGS: -lm
+*/
+import "C"
diff --git a/sqlite3_vtable.go b/sqlite3_opt_vtable.go
similarity index 99%
rename from sqlite3_vtable.go
rename to sqlite3_opt_vtable.go
index 8bef291..3391756 100644
--- a/sqlite3_vtable.go
+++ b/sqlite3_opt_vtable.go
@@ -2,7 +2,7 @@
 //
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
-// +build vtable
+// +build sqlite_vtable vtable
 
 package sqlite3
 
diff --git a/sqlite3_trace.go b/sqlite3_trace.go
index 8f90a56..999ba78 100644
--- a/sqlite3_trace.go
+++ b/sqlite3_trace.go
@@ -2,7 +2,7 @@
 //
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
-// +build trace
+// +build sqlite_trace trace
 
 package sqlite3
 
diff --git a/sqlite3_usleep_windows.go b/sqlite3_usleep_windows.go
new file mode 100644
index 0000000..d439b53
--- /dev/null
+++ b/sqlite3_usleep_windows.go
@@ -0,0 +1,39 @@
+// +build cgo
+
+// Copyright (C) 2018 G.J.R. Timmer <gjr.timmer@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+package sqlite3
+
+// usleep is a function available on *nix based systems.
+// This function is not present in Windows.
+// Windows has a sleep function but this works with seconds
+// and not with microseconds as usleep.
+//
+// This code should improve performance on windows because
+// without the presence of usleep SQLite waits 1 second.
+//
+// Source: https://stackoverflow.com/questions/5801813/c-usleep-is-obsolete-workarounds-for-windows-mingw?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa
+
+/*
+#include <windows.h>
+
+void usleep(__int64 usec)
+{
+    HANDLE timer;
+    LARGE_INTEGER ft;
+
+    // Convert to 100 nanosecond interval, negative value indicates relative time
+    ft.QuadPart = -(10*usec);
+
+    timer = CreateWaitableTimer(NULL, TRUE, NULL);
+    SetWaitableTimer(timer, &ft, 0, NULL, NULL, 0);
+    WaitForSingleObject(timer, INFINITE);
+    CloseHandle(timer);
+}
+*/
+import "C"
+
+// EOF


Test patch:
diff --git a/sqlite3_vtable_test.go b/sqlite3_opt_vtable_test.go
similarity index 99%
rename from sqlite3_vtable_test.go
rename to sqlite3_opt_vtable_test.go
index ce6a48c..51dcd0f 100644
--- a/sqlite3_vtable_test.go
+++ b/sqlite3_opt_vtable_test.go
@@ -2,7 +2,7 @@
 //
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
-// +build vtable
+// +build sqlite_vtable vtable
 
 package sqlite3