Class: Tina4::Drivers::PostgresDriver

Inherits:
Object
  • Object
show all
Includes:
SchemaSplit
Defined in:
lib/tina4/drivers/postgres_driver.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from SchemaSplit

#split_schema

Instance Attribute Details

#connection ⇒ Object (readonly)

Returns the value of attribute connection.



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# File 'lib/tina4/drivers/postgres_driver.rb', line 9

def connection
  @connection
end

Instance Method Details

#apply_limit(sql, limit, offset = 0) ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 155

def apply_limit(sql, limit, offset = 0)
  "#{sql} LIMIT #{limit} OFFSET #{offset}"
end

#begin_transaction ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 159

def begin_transaction
  @connection.exec("BEGIN")
end

#close ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 32

def close
  @connection&.close
end

#columns(table_name) ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 188

def columns(table_name)
  # v3.13.14 (#48): honour a schema-qualified name; default to public.
  schema, tbl = split_schema(table_name)
  schema ||= "public"
  sql = "SELECT column_name, data_type, is_nullable, column_default FROM information_schema.columns WHERE table_name = $1 AND table_schema = $2"
  rows = execute_query(sql, [tbl, schema])
  rows.map do |r|
    {
      name: r[:column_name],
      type: r[:data_type],
      nullable: r[:is_nullable] == "YES",
      default: r[:column_default],
      primary_key: false
    }
  end
end

#commit ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 163

def commit
  @connection.exec("COMMIT")
end

#connect(connection_string, username: nil, password: nil) ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 11

def connect(connection_string, username: nil, password: nil)
  begin
    require "pg"
  rescue LoadError
    raise LoadError,
          "The 'pg' gem is required for PostgreSQL connections. Install one of:\n" \
          "    bundle add pg     # if your project uses Bundler\n" \
          "    gem install pg    # bare driver"
  end
  url = connection_string
  if username || password
    uri = URI.parse(url)
    uri.user = username if username
    uri.password = password if password
    url = uri.to_s
  end
  @connection = PG.connect(url)
  apply_result_type_map(@connection)
  @connection
end

#execute(sql, params = []) ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 46

def execute(sql, params = [])
  # Issue #256: a bare INSERT run through execute() (not #insert, so no
  # RETURNING captured) must NOT let a previously-captured RETURNING id
  # leak into a later last_insert_id() — that would surface a stale id
  # (e.g. a UUID string from an earlier db.insert) for this new write.
  # Clear the cache so last_insert_id falls back to the lastval() probe,
  # which is the correct source for a sequence-backed bare INSERT.
  @last_returning_id = nil if sql.lstrip[0, 6].upcase == "INSERT"
  converted_sql = convert_placeholders(sql)
  if params.empty?
    @connection.exec(converted_sql)
  else
    @connection.exec_params(converted_sql, params)
  end
end

#execute_query(sql, params = []) ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 36

def execute_query(sql, params = [])
  converted_sql = convert_placeholders(sql)
  result = if params.empty?
             @connection.exec(converted_sql)
           else
             @connection.exec_params(converted_sql, params)
           end
  result.map { |row| decode_blobs(symbolize_keys(row)) }
end

#insert(table, data) ⇒ Object

Issue #256: surface the ACTUAL primary key value an INSERT wrote —including a server-generated UUID — instead of guessing it from a session sequence after the fact.

Before this, Database#insert ran a bare INSERT and then probed “last_insert_id“ (“SELECT lastval()“). For a UUID PK (“id uuid PRIMARY KEY DEFAULT gen_random_uuid()“) there is no session sequence, so the probe returned nil — or, worse, a STALE integer left over from an unrelated SERIAL table’s nextval() earlier in the same session (a silently WRONG id). The SERIAL integer path was correct only by luck of lastval() pointing at the right sequence.

Fix (mirrors the Python master’s “INSERT … RETURNING *“ and the Node adapter): append “RETURNING *“ and read the generated “id“ back from the returned row. The value is normalised so the SERIAL path keeps returning an Integer while a UUID PK surfaces its real 36-char string. No lastval() probe, so the issue-#38 transaction-abort can’t happen on this path at all.

Returns { success: true, last_id: <id-or-nil> }. last_id is nil only when the table truly has no “id“ column.



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# File 'lib/tina4/drivers/postgres_driver.rb', line 83

def insert(table, data)
  columns = data.keys.map(&:to_s)
  placeholders = placeholders(columns.length)
  sql = "INSERT INTO #{table} (#{columns.join(', ')}) VALUES (#{placeholders}) RETURNING *"
  result = execute_query(sql, data.values)
  row = result.is_a?(Array) ? result.first : nil
  id = normalize_returned_id(row)
  # Remember the real id so a follow-up #last_insert_id / db.get_last_id
  # surfaces THIS value (incl. a UUID string) instead of re-probing
  # lastval(), which has no sequence for a UUID PK and would return a
  # stale wrong integer from an unrelated table.
  @last_returning_id = id
  { success: true, last_id: id }
end

#last_insert_id ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 98

def last_insert_id
  # Issue #256: if the most recent write surfaced its real primary key
  # through ``RETURNING *`` (the #insert path), return that — it is the
  # actual id written (a UUID string stays a string, a SERIAL stays an
  # integer), not a guess. Only fall back to the lastval() probe below
  # when nothing has been captured yet (e.g. a bare
  # ``execute("INSERT ...")`` with no RETURNING).
  return @last_returning_id unless @last_returning_id.nil?

  # Issue #38: ``SELECT lastval()`` raises on tables with no sequence
  # (UUID, ULID, hash PKs etc.). The exception itself isn't fatal,
  # but the pg gem marks the whole transaction as aborted, so every
  # subsequent statement on this connection fails with
  # ``PG::InFailedSqlTransaction`` — far away from the real cause.
  #
  # Fix: wrap the probe in a SAVEPOINT. If ``lastval()`` raises, we
  # ROLLBACK TO SAVEPOINT and the outer transaction stays usable;
  # ``last_insert_id`` just returns ``nil`` (same as before for
  # tables without a sequence). On success we RELEASE SAVEPOINT.
  begin
    @connection.exec("SAVEPOINT _t4_lastval_probe")
  rescue PG::Error
    # No active transaction (autocommit/idle) — fall back to a plain
    # probe; psycopg2-style transaction abort can't happen here.
    begin
      result = @connection.exec("SELECT lastval()")
      return result.first["lastval"].to_i
    rescue PG::Error
      return nil
    end
  end

  begin
    result = @connection.exec("SELECT lastval()")
    @connection.exec("RELEASE SAVEPOINT _t4_lastval_probe")
    result.first["lastval"].to_i
  rescue PG::Error
    begin
      @connection.exec("ROLLBACK TO SAVEPOINT _t4_lastval_probe")
      @connection.exec("RELEASE SAVEPOINT _t4_lastval_probe")
    rescue PG::Error
      # If even the rollback fails, there's nothing we can do — the
      # connection is in a state we can't recover. Surface nil so
      # callers don't get a half-set last_id.
    end
    nil
  end
end

#placeholder ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 147

def placeholder
  "?"
end

#placeholders(count) ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 151

def placeholders(count)
  (1..count).map { |i| "$#{i}" }.join(", ")
end

#rollback ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 167

def rollback
  @connection.exec("ROLLBACK")
end

#table_exists?(name) ⇒ Boolean

v3.13.14 (#48): to_regclass resolves a (possibly schema-qualified) relation name and search_path like a FROM clause; nil if absent.

Returns:

  • (Boolean) 


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# File 'lib/tina4/drivers/postgres_driver.rb', line 173

def table_exists?(name)
  rows = execute_query("SELECT to_regclass($1) AS oid", [name.to_s])
  !rows.empty? && !rows[0][:oid].nil?
end

#tables ⇒ Object 



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# File 'lib/tina4/drivers/postgres_driver.rb', line 178

def tables
  # v3.13.14 (#48): list every user schema; public tables stay bare,
  # others are returned schema-qualified.
  sql = "SELECT schemaname, tablename FROM pg_tables " \
        "WHERE schemaname NOT IN ('pg_catalog', 'information_schema') " \
        "ORDER BY schemaname, tablename"
  rows = execute_query(sql)
  rows.map { |r| r[:schemaname] == "public" ? r[:tablename] : "#{r[:schemaname]}.#{r[:tablename]}" }
end