crystal-lang / crystal-sqlite3

SQLite3 bindings for Crystal

crystal-sqlite3

SQLite3 bindings for Crystal.

Check crystal-db for general db driver documentation. crystal-sqlite3 driver is registered under sqlite3:// uri.

Installation

Add this to your application's shard.yml:

dependencies:
  sqlite3:
    github: crystal-lang/crystal-sqlite3

Usage

require "sqlite3"

DB.open "sqlite3://./data.db" do |db|
  db.exec "create table contacts (name text, age integer)"
  db.exec "insert into contacts values (?, ?)", "John Doe", 30

  args = [] of DB::Any
  args << "Sarah"
  args << 33
  db.exec "insert into contacts values (?, ?)", args: args

  puts "max age:"
  puts db.scalar "select max(age) from contacts" # => 33

  puts "contacts:"
  db.query "select name, age from contacts order by age desc" do |rs|
    puts "#{rs.column_name(0)} (#{rs.column_name(1)})"
    # => name (age)
    rs.each do
      puts "#{rs.read(String)} (#{rs.read(Int32)})"
      # => Sarah (33)
      # => John Doe (30)
    end
  end
end

DB::Any

• Time is implemented as TEXT column using SQLite3::DATE_FORMAT_SUBSECOND format (or SQLite3::DATE_FORMAT_SECOND if the text does not contain a dot).
• Bool is implemented as INT column mapping 0/1 values.

Setting PRAGMAs

You can adjust certain SQLite3 PRAGMAs automatically when the connection is created by using the query parameters:

require "sqlite3"

DB.open "sqlite3://./data.db?journal_mode=wal&synchronous=normal" do |db|
  # this database now uses WAL journal and normal synchronous mode
  # (defaults were `delete` and `full`, respectively)
end

The following is the list of supported options:

Name	Connection key
Busy Timeout	busy_timeout
Cache Size	cache_size
Foreign Keys	foreign_keys
Journal Mode	journal_mode
Synchronous	synchronous
WAL autocheckoint	wal_autocheckpoint

Please note there values passed using these connection keys are passed directly to SQLite3 without check or evaluation. Using incorrect values result in no error by the library.

crystal-sqlite3's Issues

Compile error(s)

Umm, I have an interesting problem with compiling an app that uses this shard. I don't really know how to describe it, sorry 😕

I created a minimal project and just copied the readme example. On running shards build --error-trace --no-color (--no-color doesn't seem to be respected for the ^~~~ interestingly enough^^) I receive the following output (hidden via details 'cause it's a lot). I get this output no matter what I try to do with the db. All that actually does compile is DB.open [...] without any further actions.

I: Dependencies are satisfied
I: Building: sqlitetest
E: Error target sqlitetest failed to compile:
Error in src/sqlitetest.cr:5: instantiating 'DB:Module#open(String)'

  DB.open "sqlite3://./data.db" do |db|
     �[32;1m^~~~�[0m

in src/sqlitetest.cr:5: instantiating 'DB:Module#open(String)'

  DB.open "sqlite3://./data.db" do |db|
     �[32;1m^~~~�[0m

in src/sqlitetest.cr:6: instantiating 'DB::Database#exec(String)'

    db.exec "create table contacts (name string, age integer)"
       �[32;1m^~~~�[0m

in lib/db/src/db/query_methods.cr:217: instantiating 'build(String)'

      build(query).exec(*args)
      �[32;1m^~~~~�[0m

in lib/db/src/db/session_methods.cr:23: instantiating 'fetch_or_build_prepared_statement(String)'

        fetch_or_build_prepared_statement(query)
        �[32;1m^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~�[0m

in lib/db/src/db/database.cr:84: instantiating 'DB::StringKeyCache(DB::PoolPreparedStatement)#fetch(String)'

      @statements_cache.fetch(query) { build_prepared_statement(query) }
                        �[32;1m^~~~~�[0m

in lib/db/src/db/database.cr:84: instantiating 'DB::StringKeyCache(DB::PoolPreparedStatement)#fetch(String)'

      @statements_cache.fetch(query) { build_prepared_statement(query) }
                        �[32;1m^~~~~�[0m

in lib/db/src/db/database.cr:84: instantiating 'build_prepared_statement(String)'

      @statements_cache.fetch(query) { build_prepared_statement(query) }
                                       �[32;1m^~~~~~~~~~~~~~~~~~~~~~~~�[0m

in lib/db/src/db/database.cr:89: instantiating 'DB::PoolPreparedStatement:Class#new(DB::Database, String)'

      PoolPreparedStatement.new(self, query)
                            �[32;1m^~~�[0m

in lib/db/src/db/pool_prepared_statement.cr:17: instantiating 'statement_with_retry()'

      statement_with_retry &.release_connection
      �[32;1m^~~~~~~~~~~~~~~~~~~~�[0m

in lib/db/src/db/pool_statement.cr:52: instantiating 'DB::Database#retry()'

      @db.retry do
          �[32;1m^~~~~�[0m

in lib/db/src/db/database.cr:135: instantiating 'DB::Pool(DB::Connection)#retry()'

      @pool.retry do
            �[32;1m^~~~~�[0m

in lib/db/src/db/database.cr:135: instantiating 'DB::Pool(DB::Connection)#retry()'

      @pool.retry do
            �[32;1m^~~~~�[0m

in lib/db/src/db/pool_statement.cr:52: instantiating 'DB::Database#retry()'

      @db.retry do
          �[32;1m^~~~~�[0m

in lib/db/src/db/pool_statement.cr:53: instantiating 'build_statement()'

        return yield build_statement
                     �[32;1m^~~~~~~~~~~~~~~�[0m

in lib/db/src/db/pool_prepared_statement.cr:34: instantiating 'clean_connections()'

      clean_connections
      �[32;1m^~~~~~~~~~~~~~~~~�[0m

in lib/db/src/db/pool_prepared_statement.cr:42: instantiating 'Set(WeakRef(DB::Connection))#each()'

      @connections.each do |ref|
                   �[32;1m^~~~�[0m

in /usr/local/Cellar/crystal-lang/0.21.1_1/src/set.cr:149: instantiating 'Hash(WeakRef(DB::Connection), Nil)#each_key()'

    @hash.each_key do |key|
          �[32;1m^~~~~~~~�[0m

in /usr/local/Cellar/crystal-lang/0.21.1_1/src/hash.cr:336: instantiating 'each()'

    each do |key, value|
    �[32;1m^~~~�[0m

in /usr/local/Cellar/crystal-lang/0.21.1_1/src/hash.cr:336: instantiating 'each()'

    each do |key, value|
    �[32;1m^~~~�[0m

in /usr/local/Cellar/crystal-lang/0.21.1_1/src/set.cr:149: instantiating 'Hash(WeakRef(DB::Connection), Nil)#each_key()'

    @hash.each_key do |key|
          �[32;1m^~~~~~~~�[0m

in lib/db/src/db/pool_prepared_statement.cr:42: instantiating 'Set(WeakRef(DB::Connection))#each()'

      @connections.each do |ref|
                   �[32;1m^~~~�[0m

in lib/db/src/db/pool_prepared_statement.cr:43: undefined method 'value' for WeakRef(DB::Connection)

        conn = ref.value
                   �[32;1m^~~~~�[0m

================================================================================

WeakRef(DB::Connection) trace:

  lib/db/src/db/pool_prepared_statement.cr:42

          @connections.each do |ref|
                                �[32;1m^~~�[0m

I'm running macOS 10.12 if that helps. I also have sqlite3 installed via homebrew, not the outdated system default. I don't have it installed with any of the provided options though, should any of those be necessary.

--with-dbstat
	Enable the 'dbstat' virtual table
--with-docs
	Install HTML documentation
--with-fts
	Enable the FTS3 module
--with-fts5
	Enable the FTS5 module (experimental)
--with-functions
	Enable more math and string functions for SQL queries
--with-icu4c
	Enable the ICU module
--with-json1
	Enable the JSON1 extension
--with-secure-delete
	Defaults secure_delete to on
--with-session
	Enable the session extension
--with-unlock-notify
	Enable the unlock notification feature
--without-readline
	Build without readline support
--without-rtree
	Disable the R*Tree index module

Thanks for any help! 😊

Allow pkg-config to determine library location

Ref: https://forum.crystal-lang.org/t/upgrade-sqlite3-binding-version/3384/2?u=bcardiff

Unhandled exception when writing to DB

def write_entry
      args = [] of DB::Any
      args << @id
      args << @datum
      args << @ht
      args << @nt
      args << @tarif_id
      MY_DB.exec "INSERT INTO dayly VALUES(?, ?, ?, ?, ?)", args
end

When writing to the database I get the following exception:

Unhandled exception: SQLite3::Statement does not support Array(Bool | Float32 | Float64 | Int32 | Int64 | Slice(UInt8) | String | Time | Nil) params (Exception)

It worked fine with previous releases

Connection are not promptly closed when transactions are used, eventually leading to file descriptor exaustion.

For easy reproduction, just run this and wait a bit:

require "sqlite3"

puts "PID is #{Process.pid}"

DB.open("sqlite3://./test-db-feel-free-to-delete-me.sqlite") do |db|
  db.exec("CREATE TABLE IF NOT EXISTS foo (bar)")

  loop do
    db.transaction do
      db.exec("INSERT INTO foo VALUES (1)")
    end
  end
end

The PID output is so that you can browse to /proc/$PID/fd and see the number of open file descriptors accumulate.

[FEATURE] Connection param for journal mode.

Setting the journal mode isn't standardized.

Suggested url format:

DB.open "sqlite3://./data.db?journal_mode=wal"

Putting the journal mode in the connection params allows all ORM's to transparently pass through the journal mode.

Expose extended result codes in the exception

Hi,

The current Exception.code field return the primary result code. It would be nice to add a new field extented_code, using sqlite3_extended_errcode().

https://sqlite.org/rescode.html#pve

Implement support for simple, aggregate, and window functions

The create_function() support exists, and was added in order to implement the REGEX() callback function. It would be very useful to have a documented Crystal interface to sqlite3_create_function_v2() that could be used similar to this:

@db.create_function returning: Int32.class do |param1, param2|
  # ... do something, returning an Int32
end

Syntax to support returning an array, handling aggregate functions, and handling window functions would be (hopefully) similar.

In addition, for my uses, it doesn't need to be exposed through DB; this is obviously for use cases that are very specific to SQLite and not portable, so having a different interface than Database::DB would be perfectly acceptable, though obviously a lot of the functionality would have to be duplicated.

Invalid memory access if query inside rows iteration

Crystal 1.0.0 [dd40a2442] (2021-03-22)
LLVM: 10.0.0
Default target: x86_64-unknown-linux-gnu
sqlite3: version: 0.18.0

Running this code with query inside iteration, fails with Invalid memory access error:

require "sqlite3"

DB.open "sqlite3://%3amemory%3a" do |db|
    db.exec "create table t1(id integer primary key autoincrement, t text)"
    db.exec "insert into t1 (t) values ('v1')"
    db.query "select id, t from t1" do |rs|
        rs.each do
            v = db.scalar "select id from t1 limit 1"
        end
    end
end

and error:

Invalid memory access (signal 11) at address 0x0
[0x55e447408396] *Exception::CallStack::print_backtrace:(Int32 | Nil) +118
[0x55e4473f783c] __crystal_sigfault_handler +316
[0x7fb5022963c0] ???
[0x7fb50228cfc4] pthread_mutex_lock +4
[0x7fb5024ea28f] sqlite3_reset +31
[0x55e4474da30b] *SQLite3::ResultSet#do_close:Int32 +27
[0x55e4474da2bf] *SQLite3::ResultSet +63
[0x55e4473e605a] __crystal_main +1658
[0x55e4474db386] *Crystal::main_user_code<Int32, Pointer(Pointer(UInt8))>:Nil +6
[0x55e4474db1fc] *Crystal::main<Int32, Pointer(Pointer(UInt8))>:Int32 +44
[0x55e4473f15e6] main +6
[0x7fb50203d0b3] __libc_start_main +243
[0x55e4473e591e] _start +46
[0x0] ???

Travis build

I looked what's missing to run this on Travis. The build fails with a missing reference to sqlite3_close_v2. That got added in SQLite 3.7.14 but Travis runs on Ubuntu precise, thus SQLite 3.7.9. There's a PPA with 3.7.15, but it's not in the whitelist, although a request is pending, also a general request for 3.8.

So we can either wait for either of those to happen, Travis migrating to a newer Ubuntu version or look into using the legacy infrastructure which doesn't require the whitelist and the PPA.

How to use this shard on Windows 10

Hi.

I'm running Crystal natively on Windows 10 and I was wondering about how to use this shard.

Right now I have a small project with successfully installed crystal-sqlite3 shard. I also have installed sqlite3 library on my system as a dll file in a folder that is added to my path. Unfortunately it seems that my setup doesn't work out of the box, because I'm getting the following error when I'm trying to run any SQLite3 related code:

Error: Cannot locate the .lib files for the following libraries: sqlite3

I don't have any .lib files in my SQLite3 installation folder. I only have a single .dll file. Is there any way to make it work or do I need to install SQLite3 differently to also have those .lib files?

Implement support for virtual tables

Support for virtual tables in crystal-sqlite3 would be very useful. (See https://sqlite.org/vtab.html#implementation for docs)

Specifically, it would be great to be able to define a virtual table in a Crystal class, which enforces the required methods and allows overriding the ones with defaults.

For example, a Crystal implementation of the generate_series virtual table (https://sqlite.org/src/file/ext/misc/series.c) might look a little like this (I'm totally making this up, and assume a real implementation will be wildly different, the point is that it's idiomatic Crystal):

class SeriesVirtualTable < SQLite3::VirtualTable
  class_property max_row_id : Int64 = 10_i64
  module_name "generate_series"
  @row_id : Int64 = 0_i64
  declare_vtab "CREATE TABLE x(a,b)" { a: Int64, b: Int64 } # raises SQLite3::Exception::SomethingAppropriate if sqlite3_declare_vtab() fails
  def next
    @row_id += 1
  end
  def row_id
    @row_id
  end
  def eof
    @row_id >= @@max_row_id
  end
  def filter
    @row_id=0
  end
  def best_index
    {estimatedCost: 10.0, estimatedRows: @@max_row_id}
  end
  def column(id)
    case id
    when 0
      1000 + @row_id
    when 1
      2000 + @row_id
    else
      raise SQLite3::Exception.new("#{id}: row id doesn't exist")
    end
end

Hopefully the intention is clear; the details are pretty flexible. Creating the instance provides the necessary parameters as class attributes. Then it is attached to the database connection and the virtual table can be created. A separate cursor object might be needed, of course, though maybe the instance can serve as both the virtual table definition and the cursor?

Maybe the other methods (like xOpen, xClose, xBegin, xCommit, etc) can be exposed as additional methods in the class.

Eponymous, eponymous-only, and shadowed virtual tables might be different base classes.

And maybe there are no base classes, but instead modules to include into a class…

Ideas and suggestions are always welcome!

SQLite3::Connection#dump fails to read >1MB files

require "sqlite3"

mem_db = DB.open "sqlite3::memory:"
file_db = DB.open "sqlite3:test.sqlite"

mem_db.using_connection do |mem_conn|
  file_db.using_connection do |file_conn|
    file_conn.dump(mem_conn)
  end 
end

The above fails with not an error (SQLite3::Exception) when the size of test.sqlite exceeds 1024K. Works fine if I delete enough rows beforehand and issue VACUUM to get the size below 1024K. The issue is the file size, because if I don't do a VACUUM, it still fails.

Specifically, on line 77 in src/sqlite3/connection.cr, code is OKAY when the expected value is DONE.

Support for PRAGMAs via query params?

Hello folks,

Been using crystal-sqlite3 a lot recently and found a bit cumbersome to use DB#setup_connection on every codebase. Things outside of DB pool size or retry timeout cannot be controlled or passed to the lower level driver.

When looked at crystal-sqlite3 source noticed a TODO for enabling URI support for additional options:

https://github.com/crystal-lang/crystal-sqlite3/blob/master/src/sqlite3/connection.cr#L5-L6

But the recognized query parameters provided by that are quite limited.

Comparing this with other implementations of sqlite3 in other languages like Go (example mattn/go-sqlite3), saw out-of-the-box support for foreign keys, timeout and journal mode (see feature list).

Made an attempt to explore adding this, but encountered that couldn't use #exec directly from within the connection initialize, as this is being instantiated by the Pool and exec tries to access the pool to pick a connection from it, and then 💣

Saw comments in #48 about considering broader support for things like this.

The SQLite3 example of setting PRAGMAs is one, but other examples like TLS support for MySQL comes to my mind. Perhaps something for this could be added to the abstraction that allows doing these adjustments on a per-driver basis?

(perhaps should be posting this on crystal-db instead, but better ask somewhere).

Thank you in advance for your responses! 😊

❤️ ❤️ ❤️

Memory leak

require "sqlite3"

DBFILE = "test.db"

db = DB.open("sqlite3://./#{DBFILE}")
while true
    begin
        db.scalar("select padding from foo where id=#{Random.rand(100000000)}") # size matters!
    rescue DB::NoResultsError
    end
end

grows beyond 32GB of RAM on my machine in a couple of minutes.

For the setup you need:
https://www.sqlite.org/src/file/ext/misc/series.c
https://www.sqlite.org/loadext.html: gcc -g -fPIC -shared series.c -o series.so

save the lines below in setup.sql, then
cat setup.sql | sqlite3 test.db

.load ./series
.header on
.timer on
drop table if exists foo;
create table foo (id int, padding text);
insert into foo (id, padding) select value, random() from generate_series(1, 100000000) order by random();
create index foo_id_ix on foo (id);

I use crystal 1.1.1 on Ubuntu 18.04

Release for crystal db 0.4.0?

Hi @bcardiff. Same question just correct repo. :-)

Error occurs by invalid DATE_FORMAT

When I define a time column to my table, I got an error like

unexpected char: '.' (19) (Time::Format::Error)

When I read it as String, I got a format

2016-12-25 14:25:53

Is the DATE_FORMAT right?

I think it should be "%F %T".

My SQLite version is here.

3.8.10.2 2015-05-20 18:17:19 2ef4f3a5b1d1d0c4338f8243d40a2452cc1f7fe4

Upsert with new syntax from SQLIte 3.24.0 fails

Hi,

This is the error being returned:

Exception occurred: UNIQUE constraint failed: my_join_table.left_id, my_join_table.right_id

Query : INSERT INTO my_join_table(left_id,right_id) VALUES(?,?)
  ON CONFLICT(left_id) DO UPDATE SET right_id = excluded.right_id;
args : [239, 1]

That's run using the DB::QueryMethods#exec method.

If I plug in the values into that statement and run it using the sqlite client (v3.36.0) it works fine. The syntax is from this Sqlite doc.

If there's any more info you need from me, just ask. I'll use one of the older workarounds I've found until (if) this is fixed, so no pressure (but it would be nice if it's looked at 😄 )

Edit: forgive me, I forgot the library info

sqlite3:
    git: https://github.com/crystal-lang/crystal-sqlite3.git
    version: 0.18.0
  db:
    git: https://github.com/crystal-lang/crystal-db.git
    version: 0.10.1

$ crystal --version
Crystal 1.1.0 [af095d72d] (2021-07-14)

LLVM: 10.0.0
Default target: x86_64-apple-macosx

Regards,
iain

Initializing empty records with `Model.new` or `Model.build`

Today Jennifer doesn't support Model.new or Model.build without any attributes nor with a sub-set of required attributes. Is this by choice or something that slipped through?

Example:

class User < Jennifer::Model::Base
  with_timestamps

  mapping(
    id: Primary32,
    name: String,
    created_at: Time?,
    updated_at: Time?,
  )
end

User.new({:name => "Jennifer"})
Unhandled exception: Column User.age can't be casted from Nil to it's type - Int32 (Jennifer::DataTypeCasting)
  from src/models/user.cr:4:3 in '_extract_attributes'
  from src/models/user.cr:4:3 in 'initialize'
  from src/models/user.cr:4:3 in 'initialize'
  from src/models/user.cr:4:3 in 'new'
  from .icr_cRpmabygCPTixNpJwNqrZA.cr:13:3 in '__icr_exec__'
  from .icr_cRpmabygCPTixNpJwNqrZA.cr:16:26 in '__crystal_main'
  from /opt/homebrew/Cellar/crystal/1.3.2/src/crystal/main.cr:115:5 in 'main_user_code'
  from /opt/homebrew/Cellar/crystal/1.3.2/src/crystal/main.cr:101:7 in 'main'
  from /opt/homebrew/Cellar/crystal/1.3.2/src/crystal/main.cr:127:3 in 'main'


User.new
          ^--
Error: wrong number of arguments for 'User.new' (given 0, expected 1..2)

Overloads are:
 - User.new(values : Hash | NamedTuple, new_record : Bool)
 - User.new(values : Hash | NamedTuple, new_record)
 - User.new(pull : DB::ResultSet)
 - User.new(values : Hash(Symbol, AttrType) | NamedTuple)
 - User.new(values : Hash(String, AttrType))

Release a new version

Hi @bcardiff

v0.8.2 was released on Mar 21, at least 5 commit and fixes has been published on master.

Would be good to have a new release

Thanks you for maintain this shard! <3

Enable foreign key checking.

By default sqlite3 doesn't check foreign keys. For application portability and consistency with other db implmentations it should be enabled.

After reviewing a variety of projects using crystal-sqlite3

• Several of them are amber or other orm's which require mysql/pg/sqlite. +1 For consistency between databases.
• The remainder don't appear to use foreign keys. Changing the default is unlikely to affect them.

Not changing the default can also lead to broken behavior. Applications that depend on CASCADE can break when moving between other db engines and sqlite.

Invalid memory access when using `#scalar` or `#exec` directly in multi-thread mode (`-Dpreview_mt`)

Hello!

Been testing out preview_mt mode with SQLite and encountered some issues. It has been hard to reproduce this, but I was able to get a small test program:

require "sqlite3"

COUNT = 10

puts "preview_mt: ", {{ flag?(:preview_mt) }}

db = DB.open("sqlite3:data.db?journal_mode=wal&busy_timeout=5000")

COUNT.times do |i|
  spawn do
    rand_id = rand(1..500)

    puts db.scalar("SELECT age FROM contacts WHERE id = ? LIMIT 1;", rand_id).as(Int64)
  end
end

Fiber.yield

db.close

data.db contains a simple schema with 500 records in it:

require "sqlite3"

CREATE_SQL = <<-SQL
  CREATE TABLE IF NOT EXISTS contacts (
    id INTEGER PRIMARY KEY NOT NULL,
    name TEXT NOT NULL,
    age INTEGER NOT NULL
  );
SQL

INSERT_SQL = <<-SQL
  INSERT INTO contacts (id, name, age) VALUES (?, ?, ?);
SQL

DB.open("sqlite3:data.db?journal_mode=wal&busy_timeout=5000") do |db|
  db.exec CREATE_SQL

  db.transaction do
    500.times do |t|
      id = t + 1
      db.exec INSERT_SQL, id, "Name #{id}", id + 20
    end
  end
end

When compiled and executed with -Dpreview_mt, I randomly receive something like the following:

preview_mt: 
true
202
500
393
337
Invalid memory access (signal 11) at address 0x0
Unhandled exception in spawn: bad parameter or other API misuse (SQLite3::Exception)
[0x557449e450f6] *Exception::CallStack::print_backtrace:Nil +118 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
Invalid memory access (signal 11) at address 0x0
426
[0x557449e30646] ~procProc(Int32, Pointer(LibC::SiginfoT), Pointer(Void), Nil) +310 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449e450f6] *Exception::CallStack::print_backtrace:Nil +118 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x7f20a5a42520] ?? [phone] in /lib/x86_64-linux-gnu/libc.so.6
[0x557449e30646] ~procProc(Int32, Pointer(LibC::SiginfoT), Pointer(Void), Nil) +310 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x7f20a5ffbc76] sqlite3_reset +22 in /lib/x86_64-linux-gnu/libsqlite3.so.0
[0x7f20a5a42520] ?? [phone] in /lib/x86_64-linux-gnu/libc.so.6
[0x557449f2c42b] *SQLite3::ResultSet#do_close:Int32 +27 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x7f20a5ffbc76] sqlite3_reset +22 in /lib/x86_64-linux-gnu/libsqlite3.so.0
[0x557449f2c3dc] *SQLite3::ResultSet +60 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449f2c42b] *SQLite3::ResultSet#do_close:Int32 +27 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449f29f63] *DB::Statement+ +291 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449f2c3dc] *SQLite3::ResultSet +60 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449f2a7b9] *DB::PoolStatement+ +633 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449f29f63] *DB::Statement+ +291 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449f1195b] *DB::Database +59 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449f2a7b9] *DB::PoolStatement+ +633 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449e31b9b] ~procProc(Nil) +155 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449f1195b] *DB::Database +59 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449e8bc52] *Fiber#run:(IO::FileDescriptor | Nil) +114 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449e31b9b] ~procProc(Nil) +155 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449e30166] ~proc2Proc(Fiber, (IO::FileDescriptor | Nil)) +6 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x557449e8bc52] *Fiber#run:(IO::FileDescriptor | Nil) +114 in /home/luis/repos/github.com/luislavena/test-sqlite3-mt/bin/test
[0x0] ???

Sometimes receiving bad parameter or other API misuse, others unable to close due to unfinalized statements or unfinished backups

I was able to workaround this by using using_connection block instead:

COUNT.times do |i|
  spawn do
    rand_id = rand(1..500)

    db.using_connection do |conn|
      puts conn.scalar("SELECT age FROM contacts WHERE id = ? LIMIT 1;", rand_id).as(Int64)
    end
  end
end

Which points there might be an issue on how #exec, #scalar and possible other calls are handled by DB::Database and passed to one of the connections in the pool.

But even so, I will still randomly get errors (small adaptation to my example on my site).

Since I'm blowing things up, decided to put more dynamite into the issue and tried ysbaddaden/pool shard:

db = ConnectionPool(DB::Connection).new(capacity: 20) do
  DB.connect(DATABASE_URL)
end

And then:

    db.connection do |conn|
      conn.scalar("SELECT name FROM contacts WHERE id = ? LIMIT 1;", id).as(String)
    end

To my surprise, these random exceptions are gone and performance is even higher:

$ plow -c 20 -d 10s http://localhost:8080
Benchmarking http://localhost:8080 for 10s using 20 connection(s).
@ Real-time charts is listening on http://[::]:18888

Summary:
  Elapsed        10s
  Count       746816
    2xx       746816
  RPS      74681.412
  Reads    7.392MB/s
  Writes   4.131MB/s

Statistics    Min       Mean    StdDev     Max   
  Latency     29µs     266µs     804µs   35.593ms
  RPS       71105.09  74675.39  1390.64  75844.23

Latency Percentile:
  P50     P75    P90    P95     P99     P99.9   P99.99 
  146µs  169µs  201µs  257µs  6.482ms  6.658ms  6.901ms

Latency Histogram:
  149µs    632328  84.67%
  268µs     99222  13.29%
  3.697ms    7679   1.03%
  6.503ms    5546   0.74%
  6.592ms    1752   0.23%
  6.656ms     190   0.03%
  6.786ms      87   0.01%
  7.004ms      12   0.00%

Tried running this project own specs with -Dpreview_mt and fails with the same issue, so not sure where to start looking at.

Apologies for the rambling, but wanted to make sure I included all the information I think is connected and relevant, I hope is not too much.

Any ideas where I should start looking at first?

Thank you in advance.
❤️ ❤️ ❤️

Can't read BLOB type as Bytes

A column with a BLOB type, reads as whatever the type of the value is, as opposed to Bytes, which would make more sense.

DB.open "sqlite3://./data.db" do |db|
  db.exec "create table contacts (name text, data BLOG)"
  db.exec "insert into contacts values (?, ?)", "John Doe", 30

  db.query "select name, data from contacts" do |rs|
    rs.each do
      puts "#{rs.read(String)} (#{rs.read(Bytes)})"
    end
  end
end

SQLite3::ResultSet#read returned a Int64. A Slice(UInt8) was expected. (Exception)

Changing the 30 to "foo"

SQLite3::ResultSet#read returned a String. A Slice(UInt8) was expected. (Exception)

Create database instance for further usage

Inspired from the Ruby sqlite gem, here is an improvement I would like to see in the Crystal shard syntax :
Being able to create a new database object, allowing usage everywhere in the code, as opposed to only in the 'do' block. Also would allow for usage of several databases at once.
db = SQLite3::Database.new 'database.db'

You would then be able to run db.exec, db.query on this object.

undefined reference to `sqlite3_close_v2'

Hello, I'm new to crystal, I see some reference to this problem, but I don't see what I might need to do to work around the problem. From what I see, the version of sqlite3 and the driver are not compatible. What is a working combination? I simply pasted the sample from this git into a text file and attempted to run.

SQLite35858Connection.o: In function *SQLite3::Connection#do_close:Int32': SQLite3::Connection:(.text+0x403): undefined reference tosqlite3_close_v2'
collect2: error: ld returned 1 exit status

Error: execution of command failed with code: 1: cc -o "/home/eugene/workspace/harvest/harvest" "${@}" -rdynamic -lsqlite3 -lpcre -lgc -lpthread /opt/crystal/src/ext/libcrystal.a -levent -lrt -ldl -L/usr/lib -L/usr/local/lib

require "db"
require "sqlite3"


module Harvest
  # TODO Put your code here
   puts "Hello"
db = DB.open "sqlite3://data.db" 
  db.exec "create table contacts (name string, age integer)"
  db.exec "insert into contacts values (?, ?)", "John Doe", 30

#  args = [] of DB::Any
#  args << "Sarah"
#  args << 33
#  db.exec "insert into contacts values (?, ?)", args

#  puts "max age:"
#  puts db.scalar "select max(age) from contacts" # => 33

#  puts "contacts:"
#  db.query "select name, age from contacts order by age desc" do |rs|
#    puts "#{rs.column_name(0)} (#{rs.column_name(1)})"
#    # => name (age)
#    rs.each do
#      puts "#{rs.read(String)} (#{rs.read(Int32)})"
#      # => Sarah (33)
#      # => John Doe (30)
   db.close

DROP TABLE IF EXISTS issue. Exception: no such table: tablename (SQLite3::Exception)

DB.open "sqlite3:./mydb.sqlite3" do |db|
db.exec "DROP TABLE IF EXISTS tablename"
end

triggers "Exception: no such table: tablename (SQLite3::Exception)"

when:

sqlite3 mydb.sqlite3
SQLite version 3.31.1 2020-01-27 19:55:54
Enter ".help" for usage hints.
sqlite> .tables
tablename

1. table exists
2. sqlite3 implements "DROP TABLE IF EXISTS tablename" which should NOT trigger any exception.
3. crystal-sqlite3 test spec https://github.com/crystal-lang/crystal-sqlite3/blob/master/spec/db_spec.cr
   specifically invokes (lines 81-83)

drop_table_if_exists_syntax do |table_name|
"drop table if exists #{table_name}"
end

4. I cleaned cache ~/.cache/crystal/

crystal version 1.7.3

What am I doing wrong?

REGEXP support

The sqlite3 REGEXP operator relies on a user-defined regexp function which is not defined by default, so regex support requires specifying a function. Does/will this library have an API to connect Crystal's stdlib regex functionality to it?

How to use a different version of SQLite?

If I install a newer version of SQLite (e.g. in /usr/local/) how do I get crystal to use the newer binaries?

What about SQL injections?

Do you plan to allow statement with a SQL injection protection ?

Data Change Notification Hook

I've been skimming through the source and looking through the docs, and I can't find any indications that crystal-sqlite3 supports the sqlite3_update_hook callback to get "notified" when potentially interesting data is created, updated or deleted. It is similar to the PostgreSQL NOTIFY feature.

I'm not sure if the underlying DB wrapper has support for this kind of functionality yet though, but I figured I'd open an issue here nonetheless.

Does Jennifer strive for ActiveRecord method parity?

In my project I am monkey-patching some native ActiveRecord methods like:

• find_by
• find_by_and_initialize
• find_or_create_by
• Model.first instead of Model.all.first

Is the long-term vision for Jennifer to be as close as possible to AR's API or do you want to be more selective? Just want to clarify before opening any PRs. 😄

Add support for serialize/deserialize

Could you please add support for sqlite3_serialize and sqlite3_deserialize?

As a downstream app, that would allow us to manipulate database in memory only, removing the need to write data on disk!

Fail With Debian Testing

Debian Testing
Crystal 25.1
SQLITE3 installed

shards install seemed to work ok

require "kemal"
require "db"
require "sqlite3"
DB.open "sqlite3://ourwebsite.db" do |db|

/usr/bin/ld: cannot find -lsqlite3 (this usually means you need to install the development package for libsqlite3)
/usr/bin/ld: cannot find -lz (this usually means you need to install the development package for libz)
collect2: error: ld returned 1 exit status
Error: execution of command failed with code: 1: cc "${@}" -o '/home/work/.cache/crystal/crystal-run-website.tmp' -rdynamic -lsqlite3 -lz command -v pkg-config > /dev/null && pkg-config --libs --silence-errors libssl || printf %s '-lssl -lcrypto' command -v pkg-config > /dev/null && pkg-config --libs --silence-errors libcrypto || printf %s '-lcrypto' -lpcre -lm -lgc -lpthread /usr/share/crystal/src/ext/libcrystal.a -levent -lrt -ldl -L/usr/lib -L/usr/local/lib

we have tried to look for a zlib-dev but cannot find. We have this working on a Fedora 28 machine so something is missing with packages
appreciate any help

atomic last_insert_rowid

last_insert_rowid() can be used to get the autoincrement-generated ID of a row: https://stackoverflow.com/a/30715960/12211329

But this has to be atomic with the insert statement to be useful, and I'm seeing that if I execute a combined statement like db.scalar("INSERT INTO table (col1, col2) VALUES ('blah', 'blah'); SELECT last_insert_rowid()"), I get a DB::NoResultsError. It works if I execute the insert with db.exec and then the select with db.scalar, but I don't believe that's atomic.

ARM Fiber bug

I just try the 0.8.2 version with a Crystal 0.23.1 [e2a1389e8] LLVM 3.8.
There is a bug that doesn't allow sqlite to run in a spawned Fiber (which is annoying if you try to run Kemal e.g.)

The bug is easy to reproduce:
require "sqlite3"

spawn do
DB.open "sqlite3://%3Amemory%3A" do |db|
db.exec "CREATE TABLE IF NOT EXISTS contacts (name string, age integer)"
puts "=== count is #{db.scalar "select count(*) from contacts"}"
end
end
sleep 1.seconds

The execution gives:

---inside #step : #SQLite3::Statement:0x412d20 sql select count(*) from contacts
Unhandled exception in spawn:
database disk image is malformed (SQLite3::Exception)
0x72eb4: *CallStack::unwind:Array(Pointer(Void)) at /home/pi/Projects/crystal/src/float/printer/cached_powers.cr 1:1
0xd7cf0: move_next at /home/pi/Projects/CrystalThinking/lib/sqlite3/src/sqlite3/result_set.cr 20:7
0xce484: scalar at /home/pi/Projects/CrystalThinking/lib/db/src/db/statement.cr 39:13
0xcec04: scalar at /home/pi/Projects/CrystalThinking/lib/db/src/db/pool_statement.cr 44:30
0xc5268: scalar at /home/pi/Projects/CrystalThinking/lib/db/src/db/query_methods.cr 223:7
0x6e584: ~procProc(Nil) at /home/pi/Projects/crystal/src/time/format/pattern.cr 1:1
0x83260: run at /home/pi/Projects/crystal/src/fiber.cr 255:3
0x6d834: ~proc2Proc(Fiber, (IO::FileDescriptor | Nil)) at /home/pi/Projects/crystal/src/concurrent.cr 61:3

Support additional DateTime formats and common datetime queries

Currently (0.8.1) when reading/writing Time values the format SQLite3::DATE_FORMAT is used. This is one of the supported formats by sqlite. It is actually the one with more precision: YYYY-MM-DD HH:MM:SS.SSS

This is enough for reading/writing values using Time crystal's type. But it would be proper to allow reading time values using a fallback for all other DateTime formats described in https://www.sqlite.org/lang_datefunc.html so the following queries will work:

• select date('now');
• select datetime('now');
• SELECT current_timestamp;

This should be handled in

crystal-sqlite3/src/sqlite3/result_set.cr

Line 59 in 9784573

Time.parse read(String), SQLite3::DATE_FORMAT

Query methods raise if instructed to read String consisting entirely out of digits

Minimal Example:

require "db"
require "sqlite3"

DB.open("sqlite3://test.db") do |db|
  db.exec("create table if not exists foo (bar string);")
  db.exec("insert into foo (bar) values (?);", "42")
  pp db.query_all("select * from foo;", as: String)
end

Output:

[nix-shell:~/tmp/sqlite-crash-reduction]$ shards build && bin/sqlite-crash-reduction 
Dependencies are satisfied
Building: sqlite-crash-reduction
Unhandled exception: SQLite3::ResultSet#read returned a Int64. A String was expected. (Exception)
  from lib/db/src/db/result_set.cr:0:9 in 'read'
  from lib/db/src/db/query_methods.cr:249:9 in 'query_all:as'
  from src/sqlite-crash-reduction.cr:7:6 in '__crystal_main'
  from /nix/store/1j9vv8lxl38ylhx970fbcfnplari4gl1-crystal-0.30.1/lib/crystal/crystal/main.cr:97:5 in 'main_user_code'
  from /nix/store/1j9vv8lxl38ylhx970fbcfnplari4gl1-crystal-0.30.1/lib/crystal/crystal/main.cr:86:7 in 'main'
  from /nix/store/1j9vv8lxl38ylhx970fbcfnplari4gl1-crystal-0.30.1/lib/crystal/crystal/main.cr:106:3 in 'main'
  from __libc_start_main
  from ../sysdeps/x86_64/start.S:122:0 in '_start'
  from ???

Versions:
crystal 0.30.1
sqlite3 3.28.0
crystal-db 0.7.0
crystal-sqlite3 0.14.0

A workaround is reading strings as DB::Any initially and later running to_s on them.

Executed statements which return multiple rows will result in an exception

While attempting to execute a particular PRAGMA statement, my application crashed with an "unknown error".

Crystal / shard versions

• Crystal: 0.23.1
• sqlite3: 0.8.2
• db: 0.4.2

Example code

require "db"
require "sqlite3"

DB.open "sqlite3://./tester.db" do |db|
  db.exec("PRAGMA journal_mode = memory")
end

Execution result

$ crystal run example.cr 
unknown error (SQLite3::Exception)
0x55c42a4f6f4d: perform_exec at /tmp/pragma-crystal-sqlite3/lib/sqlite3/src/sqlite3/statement.cr 25:40
0x55c42a4f766d: perform_exec_and_release at /tmp/pragma-crystal-sqlite3/lib/db/src/db/statement.cr 97:14
0x55c42a4f75f9: exec at /tmp/pragma-crystal-sqlite3/lib/db/src/db/statement.cr 67:7
0x55c42a4f7ac9: exec at /tmp/pragma-crystal-sqlite3/lib/db/src/db/pool_statement.cr 14:30
0x55c42a4eeb55: exec at /tmp/pragma-crystal-sqlite3/lib/db/src/db/query_methods.cr 217:7
0x55c42a488952: __crystal_main at /tmp/pragma-crystal-sqlite3/example.cr 5:3
0x55c42a498159: main at /usr/lib/crystal/main.cr 12:15
0x7f2efbf24f6a: __libc_start_main at ??
0x55c42a4880fa: _start at ??
0x0: ??? at ??

The PRAGMA statement given in the example code returns a LibSQLite3::Code::ROW after being stepped once. It appears that this statement needs more than one step before it is considered done.

Crash when querying on ARM (Failed to raise an exception: FAILURE)

• Crystal version: 0.33.0
• LLVM: 8.0.0

Here's a minimal example to reproduce

require "sqlite3"

puts "creating DB"

DB.open "sqlite3://./test.db" do |db|
  db.exec "create table if not exists test (number integer)"
end

puts "DB created. Querying"

DB.open "sqlite3://./test.db" do |db|
  begin
    db.query_one "select * from test where number = 1" do |rs|
      pp rs
    end
  rescue e
    puts e
  end
end

Console output when running on an armhf device (tested on a Raspberry Pi 3):

creating DB
DB created. Querying
Failed to raise an exception: FAILURE
[0x0] ???

The same code works as expected on amd64.

Invalid memory access (signal 11) at address 0x0

Invalid memory access (signal 11) at address 0x0
[0x55eb4f123e66] *Exception::CallStack::print_backtrace:Nil +118 in bin/translater
[0x55eb4f1048e6] ~procProc(Int32, Pointer(LibC::SiginfoT), Pointer(Void), Nil) +310 in bin/translater
[0x7f828811c770] ?? [phone] in /usr/lib/libc.so.6
[0x0] ???

I can reproduce this on my recent version translater.
it is an simple app with infrequent access to SQL.

reproduce

1. clone https://github.com/crystal-china/translater and switch to sqlite3_exception branch.
2. shards install
3. shards build
4. run bin/translater -e baidu,bing 'hello world'

As you can see, it raise Invalid memory access this time, but it work on next time.

the broken code is here, when insert into two table in same db file in a times loop.

Anyway, i thiought whatever happen don't should cause a Invalid memory access.

Add a sleep 0.1 after this line, seem like fix this issue.

BTW: same issue happen both on use DB.connect or DB.open.

Test on Crystal 1.12.0

Thanks

Sample DB

Well, it's not an issue really, but it'd be nice if a sample db would be included sample program. It'll save some time to start testing/experimenting ...

Investigate: performance bottleneck when running in multi-thread scenarios

Decided to separate this from #87, as it relates to performance and not necessarily the exception experienced in the original report.

Using luislavena/test-crystal-sqlite3-db repository/app, run a few benchmarks single-thread vs multi-thread vs other pooling mechanisms and found that it appears that the usage of double mutexes (connection pool and prepared statement pool) cause a bottleneck when running in mutli-concurrency scenarios.

Based on #87 (fix-mt branch) build, all this is run and tested on 4C/8T AMD Ryzen CPU, static (musl) and release mode builds, natively (no containers or VMs) using plow locally (localhost), no network latency involved. Tests were performed multiple times after warm up processes and pick the best of 3 runs.

---

fix-mt build:

Single thread build:

• 1 connection: ~18K RPS
• 5 connections: ~43.5K RPS
• 10 connections: ~43.9K RPS
• 20 connections: ~44.5K RPS

CRYSTAL_WORKERS=4, multi-thread:

• 1 connection: ~14K RPS
• 5 connections: ~7.8K RPS
• 10 connections: ~10K RPS
• 20 connections: ~10K RPS

CRYSTAL_WORKERS=8, multi-thread:

• 1 connection: ~12K RPS
• 5 connections: ~7.8K RPS
• 10 connections: ~8.5K RPS
• 20 connections: ~9.5K RPS

---

Same as above, but replaced DB.open with DB.connect and usage of DB's pool with Syn::Pool wrap around DB::Connection, (see exp-syn-pool branch)

Single-thread build:

• 1 connection: ~20K RPS
• 5 connections: ~44.6K RPS
• 10 connections: ~45.7K RPS
• 20 connections: ~45.9K RPS

CRYSTAL_WORKERS=4, multi-thread:

• 1 connection: ~12.9K RPS
• 5 connections: ~54.8K RPS
• 10 connections: ~49.8K RPS
• 20 connections: ~82.1K RPS

CRYSTAL_WORKERS=8, multi-thread:

• 1 connection: ~11.9K RPS
• 5 connections: ~53K RPS
• 10 connections: ~48.3K RPS
• 20 connections: ~57.9K RPS

---

For reference, as baseline, a no-op HTTP server app (Eg. Hello world) in similar scenarios:

Single-thread build, same concurrency:

• 1 connection: ~25.6K RPS
• 5 connections: ~71.7K RPS
• 10 connections: ~73K RPS
• 20 connections: ~74.8K RPS

CRYSTAL_WORKERS=4, multi-thread:

• 1 connection: ~16K RPS
• 5 connections: ~70K RPS
• 10 connections: ~79K RPS
• 20 connections: ~127K RPS

CRYSTAL_WORKERS=8, multi-thread:

• 1 connection: ~17.5K RPS
• 5 connections: ~53.9K RPS
• 10 connections: ~84.9K RPS
• 20 connections: ~84.2K RPS

---

Some notes:

On 10 concurrent connections:

Single-thread, noop: ~73K RPS
Single-thread, fix-mt: ~43.9K RPS
Single-thread, Syn::Pool: ~45.7K RPS

Conclusion: not much overhead.

Multi-thread (4), noop: ~79K RPS
Multi-thread (4), fix-mt: ~10K RPS
Multi-thread (4), Syn::Pool: ~49.8K RPS

Conclusion: hit bottleneck

I will perform a deeper performance analysis on this and come back with more details.

[Info] Generated binding available

Hello,
I wrote a kind of generator, and, as I generated sqlite3 bindings to test it, I though you may be interested :
The generated file is here : https://github.com/TechMagister/bindgencr/blob/master/samples/sqlite3/lib_sqlite3.cr
The project : https://github.com/TechMagister/bindgencr/

Exception handling : Desired clarifications

Hi,
I am trying to understand how exceptions are handled in Crystal-sqlite3.
Given the following code :

require "sqlite3"
DBCONN = DB.connect "sqlite3://%3Amemory%3A"
begin
  DBCONN.exec "create table test ( id integer primary key, code text not null unique)"
  DBCONN.exec "insert into test(code) values('A')"
  DBCONN.exec "insert into test(code) values('A')"
rescue e
  if e.message =~ /UNIQUE constraint failed/i
    puts ("Already in database")
  else
    puts (e.message)
  end
ensure
  DBCONN.close
end

output is :

Already in database
Unhandled exception: UNIQUE constraint failed: test.code (SQLite3::Exception)
from lib/sqlite3/src/sqlite3/statement.cr:81:5 in 'check'
from lib/sqlite3/src/sqlite3/statement.cr:37:5 in 'do_close'
from lib/db/src/db/disposable.cr:11:7 in 'close'
from lib/db/src/db/connection.cr:60:38 in 'do_close'
from lib/sqlite3/src/sqlite3/connection.cr:34:5 in 'do_close'
from lib/db/src/db/disposable.cr:11:7 in 'close'
from test1a.cr:14:3 in '__crystal_main'
from /usr/lib/crystal/crystal/main.cr:97:5 in 'main_user_code'
from /usr/lib/crystal/crystal/main.cr:86:7 in 'main'
from /usr/lib/crystal/crystal/main.cr:106:3 in 'main'
from __libc_start_main
from _start
from ???

Why does Crystal tell me the exception is unhandled when the displayed message in the rescue clause "proves" it was rescued ?

I noticed that if I comment out the DBCONN.close statement, I only get the "Already in database" message, no more unhandled exception.

If however, I run the following program :

require "sqlite3"
DBCONN = DB.connect "sqlite3://%3Amemory%3A"
begin
  DBCONN.exec "create table test ( id integer primary key, code text not null unique)"
  DBCONN.exec "insert into test(code) values('A')"
  sql = "select 1 from test where code = 'Z'"
  code = DBCONN.query_one sql, as: {String}
rescue e
  puts (e.message)
ensure
  DBCONN.close
end

the output is a bare

no rows

So, no more unhandled exception and I'm somewhat puzzled : can you enlighten me on this?
Are there different "levels" of exceptions ?
I also noticed that putting the DBCONN.close in an at_exit statement produce the same "unhandled exception" for the first code snippet.

Thanks

Result set cannot read timestamps

Database:

sqlite> .schema
CREATE TABLE IF NOT EXISTS "things"(id bigserial primary key, created_at text);
sqlite> select * from things;
1|2020-11-14 21:56:52

Code:

require "sqlite3"

DB.open("sqlite3:./test.db") do |db|
  db.query "select * from things" do |rs|
    rs.each do
      puts "#{rs.read(Int64)}, #{rs.read(Time)}"
    end
  end
end

Output:

Unhandled exception: Unexpected char: '\u{0}' at 19: "2020-11-14 21:56:52>>" (Time::Format::Error)
  from ../../../../usr/lib/crystal/time/format/parser.cr:558:11 in 'raise'
  from ../../../../usr/lib/crystal/time/format/parser.cr:554:5 in 'raise'
  from ../../../../usr/lib/crystal/time/format/parser.cr:474:9 in 'char'
  from ../../../../usr/lib/crystal/time/format/pattern.cr:165:9 in 'check_char'
  from ../../../../usr/lib/crystal/time/format/pattern.cr:8:18 in 'visit'
  from ../../../../usr/lib/crystal/time/format.cr:83:5 in 'parse'
  from ../../../../usr/lib/crystal/time/format.cr:81:3 in 'parse'
  from ../../../../usr/lib/crystal/time.cr:1181:5 in 'parse'
  from lib/sqlite3/src/sqlite3/result_set.cr:67:5 in 'read'
  from test.cr:6:34 in '__crystal_main'
  from ../../../../usr/lib/crystal/crystal/main.cr:105:5 in 'main_user_code'
  from ../../../../usr/lib/crystal/crystal/main.cr:91:7 in 'main'
  from ../../../../usr/lib/crystal/crystal/main.cr:114:3 in 'main'
  from __libc_start_main
  from _start
  from ???

However, this is the timestamp format used by SQLite's current_timestamp, so not being able to parse it is a problem. I'm not sure if the appropriate solution is a change here or somewhere else, but I'm posting it here as a starting point.

Occurs on master branch.