n00b question (db locking)

[Ariel Girón]

What is this about?

[agiron@useclwslpv132 06/17/16 03:31 PM dropbox]$ cat test3.rb
require "sqlite3"

# Open a database
db = SQLite3::Database.new "test.db"

# Create a database
rows = db.execute <<-SQL
  create table numbers (
    name varchar(30),
    val int
  );
SQL

# Execute a few inserts
{
  "one" => 1,
  "two" => 2,
}.each do |pair|
  db.execute "insert into numbers values ( ?, ? )", pair
end

# Find a few rows
db.execute( "select * from numbers" ) do |row|
  p row
end
[agiron@useclwslpv132 06/17/16 03:32 PM dropbox]$ ruby test3.rb
/usr/local/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.11/lib/sqlite3/statement.rb:108:in `step': database is locked (SQLite3::BusyException)
        from /usr/local/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.11/lib/sqlite3/statement.rb:108:in `block in each'
        from /usr/local/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.11/lib/sqlite3/statement.rb:107:in `loop'
        from /usr/local/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.11/lib/sqlite3/statement.rb:107:in `each'
        from /usr/local/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.11/lib/sqlite3/database.rb:158:in `to_a'
        from /usr/local/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.11/lib/sqlite3/database.rb:158:in `block in execute'
        from /usr/local/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.11/lib/sqlite3/database.rb:95:in `prepare'
        from /usr/local/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.11/lib/sqlite3/database.rb:134:in `execute'
        from test3.rb:7:in `<main>'
[agiron@useclwslpv132 06/17/16 03:32 PM dropbox]$

[Aaron Patterson]

I'm not sure.  I can't seem to reproduce this error.  What version of libsqlite are you using?  You should be able to get that from `SQLite3.libversion`.  Also, what version of Ruby are you using? Does it only happen with that version of Ruby?

Thanks.

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[Eric Wong]

Ariel Girón <ariel...@gmail.com> wrote:
> `step': database is locked (SQLite3::BusyException)

I normally use immediate transactions and busy_timeout=5000
(5 seconds, the Sequel default) to avoid these errors.

But there's nothing in your script which would indicate there's
concurrent access (unless you have another forgotten process
running).

I can't reproduce the error, either.

Does setting the busy_timeout help?

db = SQLite3::Database.new "test.db"

db.busy_timeout = 5000
<rest of your script>


Otherwise, it might help to provide an strace dump if you're
running under Linux. Something along the lines of:

strace -f -o dump.txt -v ruby test.rb

and show us the relevant contents of dump.txt leading up to the
failure (be sure to filter out any potentially sensitive info
from that file)