Sunday 11 September 2011

Minimal Sqlite library size

The Sqlite website states that the library size should be around 300KB, and that by omitting optional features it was possible to get the file size down to 180KB.

SQLite is a compact library. With all features enabled, the library size can be less than 300KiB, depending on compiler optimization settings. (Some compiler optimizations such as aggressive function inlining and loop unrolling can cause the object code to be much larger.) If optional features are omitted, the size of the SQLite library can be reduced below 180KiB.
There are also disclaimers that omitting optional features is unsupported and not guaranteed to work.
Important Note: The SQLITE_OMIT_* compile-time options are unsupported.
And there are three out of the many which do not work. When they are specified, compilation errors due to other external code depending on parts of them.
  • SQLITE_OMIT_COMPLETE
  • SQLITE_OMIT_DISKIO
  • SQLITE_OMIT_GET_TABLE
Which leaves the following options that do work:
nmake "OPTS=-DSQLITE_OMIT_ALTERTABLE -DSQLITE_OMIT_ANALYZE -DSQLITE_OMIT_ATTACH -DSQLITE_OMIT_AUTHORIZATION -DSQLITE_OMIT_AUTOINCREMENT -DSQLITE_OMIT_AUTOINIT -DSQLITE_OMIT_AUTOMATIC_INDEX -DSQLITE_OMIT_AUTORESET -DSQLITE_OMIT_AUTOVACUUM -DSQLITE_OMIT_CAST -DSQLITE_OMIT_BETWEEN_OPTIMIZATION -DSQLITE_OMIT_BLOB_LITERAL -DSQLITE_OMIT_BUILTIN_TEST -DSQLITE_OMIT_BTREE_COUNT -DSQLITE_OMIT_CHECK -DSQLITE_OMIT_COMPILEOPTION_DIAGS -DSQLITE_OMIT_COMPOUND_SELECT -DSQLITE_OMIT_DATETIME_FUNCS -DSQLITE_OMIT_DECLTYPE -DSQLITE_OMIT_EXPLAIN -DSQLITE_OMIT_FLAG_PRAGMAS -DSQLITE_OMIT_FLOATING_POINT -DSQLITE_OMIT_FOREIGN_KEY -DSQLITE_OMIT_INCRBLOB -DSQLITE_OMIT_INTEGRITY_CHECK -DSQLITE_OMIT_LIKE_OPTIMIZATION -DSQLITE_OMIT_LOAD_EXTENSION -DSQLITE_OMIT_LOCALTIME -DSQLITE_OMIT_LOOKASIDE -DSQLITE_OMIT_MEMORYDB -DSQLITE_OMIT_OR_OPTIMIZATION -DSQLITE_OMIT_PAGER_PRAGMAS -DSQLITE_OMIT_PRAGMA -DSQLITE_OMIT_PROGRESS_CALLBACK -DSQLITE_OMIT_QUICKBALANCE -DSQLITE_OMIT_REINDEX -DSQLITE_OMIT_SCHEMA_PRAGMAS -DSQLITE_OMIT_SCHEMA_VERSION_PRAGMAS -DSQLITE_OMIT_SHARED_CACHE -DSQLITE_OMIT_SUBQUERY -DSQLITE_OMIT_TCL_VARIABLE -DSQLITE_OMIT_TEMPDB -DSQLITE_OMIT_TRACE -DSQLITE_OMIT_TRIGGER -DSQLITE_OMIT_TRUNCATE_OPTIMIZATION -DSQLITE_OMIT_VACUUM -DSQLITE_OMIT_UTF16 -DSQLITE_OMIT_VIEW -DSQLITE_OMIT_VIRTUALTABLE -DSQLITE_OMIT_WAL -DSQLITE_OMIT_XFER_OPT" -f makefile.msc all dll
Additionally there are some other features that can be disabled by modifying the makefile before compilation.
MAKEFILE_NAME = "Makefile.msc"
s = open(MAKEFILE_NAME, "r").read()
s = s.replace("OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_FTS3=1",
    "# OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_FTS3=1")
s = s.replace("OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_RTREE=1",
    "# OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_RTREE=1")
s = s.replace("OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_COLUMN_METADATA=1",
    "# OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_COLUMN_METADATA=1")
s = s.replace("-O2", "-Os")
open(MAKEFILE_NAME, "w").write(s)
And gives the minimal file sizes of:
381,162 libsqlite3.lib
373,588 sqlite3.lo
382,464 sqlite3.exe
327,680 sqlite3.dll
This is not quite as simple (or perhaps achievable) as advertised. My current assumption is that the Sqlite website is four or five years out of date in describing what is possible.