</sect2>
- <sect2>
+ <sect2 id="plpython-trapping">
<title>Trapping Errors</title>
<para>
</sect2>
</sect1>
+ <sect1 id="plpython-subtransaction">
+ <title>Explicit Subtransactions</title>
+
+ <para>
+ Recovering from errors caused by database access as described in
+ <xref linkend="plpython-trapping"> can lead to an undesirable
+ situation where some operations succeed before one of them fails,
+ and after recovering from that error the data is left in an
+ inconsistent state. PL/Python offers a solution to this problem in
+ the form of explicit subtransactions.
+ </para>
+
+ <sect2>
+ <title>Subtransaction Context Managers</title>
+
+ <para>
+ Consider a function that implements a transfer between two
+ accounts:
+<programlisting>
+CREATE FUNCTION transfer_funds() RETURNS void AS $$
+try:
+ plpy.execute("UPDATE accounts SET balance = balance - 100 WHERE account_name = 'joe'")
+ plpy.execute("UPDATE accounts SET balance = balance + 100 WHERE account_name = 'mary'")
+except plpy.SPIError, e:
+ result = "error transferring funds: %s" % e.args
+else:
+ result = "funds transferred correctly"
+plan = plpy.prepare("INSERT INTO operations (result) VALUES ($1)", ["text"])
+plpy.execute(plan, [result])
+$$ LANGUAGE plpythonu;
+</programlisting>
+ If the second <literal>UPDATE</literal> statement results in an
+ exception being raised, this function will report the error, but
+ the result of the first <literal>UPDATE</literal> will
+ nevertheless be committed. In other words, the funds will be
+ withdrawn from Joe's account, but will not be transferred to
+ Mary's account.
+ </para>
+
+ <para>
+ To avoid such issues, you can wrap your
+ <literal>plpy.execute</literal> calls in an explicit
+ subtransaction. The <literal>plpy</literal> module provides a
+ helper object to manage explicit subtransactions that gets created
+ with the <literal>plpy.subtransaction()</literal> function.
+ Objects created by this function implement the
+ <ulink url="http://docs.python.org/library/stdtypes.html#context-manager-types">
+ context manager interface</ulink>. Using explicit subtransactions
+ we can rewrite our function as:
+<programlisting>
+CREATE FUNCTION transfer_funds2() RETURNS void AS $$
+try:
+ with plpy.subtransaction():
+ plpy.execute("UPDATE accounts SET balance = balance - 100 WHERE account_name = 'joe'")
+ plpy.execute("UPDATE accounts SET balance = balance + 100 WHERE account_name = 'mary'")
+except plpy.SPIError, e:
+ result = "error transferring funds: %s" % e.args
+else:
+ result = "funds transferred correctly"
+plan = plpy.prepare("INSERT INTO operations (result) VALUES ($1)", ["text"])
+plpy.execute(plan, [result])
+$$ LANGUAGE plpythonu;
+</programlisting>
+ Note that the use of <literal>try/catch</literal> is still
+ required. Otherwise the exception would propagate to the top of
+ the Python stack and would cause the whole function to abort with
+ a <productname>PostgreSQL</productname> error, so that the
+ <literal>operations</literal> table would not have any row
+ inserted into it. The subtransaction context manager does not
+ trap errors, it only assures that all database operations executed
+ inside its scope will be atomically committed or rolled back. A
+ rollback of the subtransaction block occurrs on any kind of
+ exception exit, not only ones caused by errors originating from
+ database access. A regular Python exception raised inside an
+ explicit subtransaction block would also cause the subtransaction
+ to be rolled back.
+ </para>
+ </sect2>
+
+ <sect2>
+ <title>Older Python Versions</title>
+
+ <para>
+ Context managers syntax using the <literal>with</literal> keyword
+ is available by default in Python 2.6. If using PL/Python with an
+ older Python version, it is still possible to use explicit
+ subtransactions, although not as transparently. You can call the
+ subtransaction manager's <literal>__enter__</literal> and
+ <literal>__exit__</literal> functions using the
+ <literal>enter</literal> and <literal>exit</literal> convenience
+ aliases. The example function that transfers funds could be
+ written as:
+<programlisting>
+CREATE FUNCTION transfer_funds_old() RETURNS void AS $$
+try:
+ subxact = plpy.subtransaction()
+ subxact.enter()
+ try:
+ plpy.execute("UPDATE accounts SET balance = balance - 100 WHERE account_name = 'joe'")
+ plpy.execute("UPDATE accounts SET balance = balance + 100 WHERE account_name = 'mary'")
+ except:
+ import sys
+ subxact.exit(*sys.exc_info())
+ raise
+ else:
+ subxact.exit(None, None, None)
+except plpy.SPIError, e:
+ result = "error transferring funds: %s" % e.args
+else:
+ result = "funds transferred correctly"
+
+plan = plpy.prepare("INSERT INTO operations (result) VALUES ($1)", ["text"])
+plpy.execute(plan, [result])
+$$ LANGUAGE plpythonu;
+</programlisting>
+ </para>
+
+ <note>
+ <para>
+ Although context managers were implemented in Python 2.5, to use
+ the <literal>with</literal> syntax in that version you need to
+ use a <ulink
+ url="http://docs.python.org/release/2.5/ref/future.html">future
+ statement</ulink>. Because of implementation details, however,
+ you cannot use future statements in PL/Python functions.
+ </para>
+ </note>
+ </sect2>
+ </sect1>
+
<sect1 id="plpython-util">
<title>Utility Functions</title>
<para>
plpython_unicode \
plpython_quote \
plpython_composite \
+ plpython_subtransaction \
plpython_drop
# where to find psql for running the tests
PSQLDIR = $(bindir)
plpython_unicode_0.out server encoding != SQL_ASCII and client encoding != UTF8; else ...
plpython_unicode_3.out server encoding == SQL_ASCII
+plpython_subtransaction_0.out Python 2.5 and older (without with statement)
+
plpython_types_3.out Python 3.x
Note: Building with Python 2.2 is supported, but there are no expected
--- /dev/null
+--
+-- Test explicit subtransactions
+--
+-- Test table to see if transactions get properly rolled back
+CREATE TABLE subtransaction_tbl (
+ i integer
+);
+-- Explicit case for Python <2.6
+CREATE FUNCTION subtransaction_test(what_error text = NULL) RETURNS text
+AS $$
+import sys
+subxact = plpy.subtransaction()
+subxact.__enter__()
+exc = True
+try:
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ if what_error == "SPI":
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('oops')")
+ elif what_error == "Python":
+ plpy.attribute_error
+ except:
+ exc = False
+ subxact.__exit__(*sys.exc_info())
+ raise
+finally:
+ if exc:
+ subxact.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_test();
+ subtransaction_test
+---------------------
+
+(1 row)
+
+SELECT * FROM subtransaction_tbl;
+ i
+---
+ 1
+ 2
+(2 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_test('SPI');
+ERROR: plpy.SPIError: invalid input syntax for integer: "oops"
+LINE 1: INSERT INTO subtransaction_tbl VALUES ('oops')
+ ^
+QUERY: INSERT INTO subtransaction_tbl VALUES ('oops')
+CONTEXT: PL/Python function "subtransaction_test"
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_test('Python');
+ERROR: AttributeError: 'module' object has no attribute 'attribute_error'
+CONTEXT: PL/Python function "subtransaction_test"
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Context manager case for Python >=2.6
+CREATE FUNCTION subtransaction_ctx_test(what_error text = NULL) RETURNS text
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ if what_error == "SPI":
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('oops')")
+ elif what_error == "Python":
+ plpy.attribute_error
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_ctx_test();
+ subtransaction_ctx_test
+-------------------------
+
+(1 row)
+
+SELECT * FROM subtransaction_tbl;
+ i
+---
+ 1
+ 2
+(2 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_ctx_test('SPI');
+ERROR: plpy.SPIError: invalid input syntax for integer: "oops"
+LINE 1: INSERT INTO subtransaction_tbl VALUES ('oops')
+ ^
+QUERY: INSERT INTO subtransaction_tbl VALUES ('oops')
+CONTEXT: PL/Python function "subtransaction_ctx_test"
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_ctx_test('Python');
+ERROR: AttributeError: 'module' object has no attribute 'attribute_error'
+CONTEXT: PL/Python function "subtransaction_ctx_test"
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Nested subtransactions
+CREATE FUNCTION subtransaction_nested_test(swallow boolean = 'f') RETURNS text
+AS $$
+plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ try:
+ with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (3)")
+ plpy.execute("error")
+ except plpy.SPIError, e:
+ if not swallow:
+ raise
+ plpy.notice("Swallowed %r" % e)
+return "ok"
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_nested_test();
+ERROR: plpy.SPIError: syntax error at or near "error"
+LINE 1: error
+ ^
+QUERY: error
+CONTEXT: PL/Python function "subtransaction_nested_test"
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_nested_test('t');
+NOTICE: Swallowed SPIError('syntax error at or near "error"',)
+CONTEXT: PL/Python function "subtransaction_nested_test"
+ subtransaction_nested_test
+----------------------------
+ ok
+(1 row)
+
+SELECT * FROM subtransaction_tbl;
+ i
+---
+ 1
+ 2
+(2 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Nested subtransactions that recursively call code dealing with
+-- subtransactions
+CREATE FUNCTION subtransaction_deeply_nested_test() RETURNS text
+AS $$
+plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ plpy.execute("SELECT subtransaction_nested_test('t')")
+return "ok"
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_deeply_nested_test();
+NOTICE: Swallowed SPIError('syntax error at or near "error"',)
+CONTEXT: PL/Python function "subtransaction_nested_test"
+SQL statement "SELECT subtransaction_nested_test('t')"
+PL/Python function "subtransaction_nested_test"
+ subtransaction_deeply_nested_test
+-----------------------------------
+ ok
+(1 row)
+
+SELECT * FROM subtransaction_tbl;
+ i
+---
+ 1
+ 2
+ 1
+ 2
+(4 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Error conditions from not opening/closing subtransactions
+CREATE FUNCTION subtransaction_exit_without_enter() RETURNS void
+AS $$
+plpy.subtransaction().__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_enter_without_exit() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_exit_twice() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+plpy.subtransaction().__exit__(None, None, None)
+plpy.subtransaction().__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_enter_twice() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+plpy.subtransaction().__enter__()
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_exit_same_subtransaction_twice() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.__enter__()
+s.__exit__(None, None, None)
+s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_enter_same_subtransaction_twice() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.__enter__()
+s.__enter__()
+s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+-- No warnings here, as the subtransaction gets indeed closed
+CREATE FUNCTION subtransaction_enter_subtransaction_in_with() RETURNS void
+AS $$
+with plpy.subtransaction() as s:
+ s.__enter__()
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_exit_subtransaction_in_with() RETURNS void
+AS $$
+with plpy.subtransaction() as s:
+ s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_exit_without_enter();
+ERROR: ValueError: this subtransaction has not been entered
+CONTEXT: PL/Python function "subtransaction_exit_without_enter"
+SELECT subtransaction_enter_without_exit();
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_enter_without_exit"
+ subtransaction_enter_without_exit
+-----------------------------------
+
+(1 row)
+
+SELECT subtransaction_exit_twice();
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_exit_twice"
+ERROR: ValueError: this subtransaction has not been entered
+CONTEXT: PL/Python function "subtransaction_exit_twice"
+SELECT subtransaction_enter_twice();
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_enter_twice"
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_enter_twice"
+ subtransaction_enter_twice
+----------------------------
+
+(1 row)
+
+SELECT subtransaction_exit_same_subtransaction_twice();
+ERROR: ValueError: this subtransaction has already been exited
+CONTEXT: PL/Python function "subtransaction_exit_same_subtransaction_twice"
+SELECT subtransaction_enter_same_subtransaction_twice();
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_enter_same_subtransaction_twice"
+ERROR: ValueError: this subtransaction has already been entered
+CONTEXT: PL/Python function "subtransaction_enter_same_subtransaction_twice"
+SELECT subtransaction_enter_subtransaction_in_with();
+ERROR: ValueError: this subtransaction has already been entered
+CONTEXT: PL/Python function "subtransaction_enter_subtransaction_in_with"
+SELECT subtransaction_exit_subtransaction_in_with();
+ERROR: ValueError: this subtransaction has already been exited
+CONTEXT: PL/Python function "subtransaction_exit_subtransaction_in_with"
+-- Make sure we don't get a "current transaction is aborted" error
+SELECT 1 as test;
+ test
+------
+ 1
+(1 row)
+
+-- Mix explicit subtransactions and normal SPI calls
+CREATE FUNCTION subtransaction_mix_explicit_and_implicit() RETURNS void
+AS $$
+p = plpy.prepare("INSERT INTO subtransaction_tbl VALUES ($1)", ["integer"])
+try:
+ with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute(p, [2])
+ plpy.execute(p, ["wrong"])
+except plpy.SPIError:
+ plpy.warning("Caught a SPI error from an explicit subtransaction")
+
+try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute(p, [2])
+ plpy.execute(p, ["wrong"])
+except plpy.SPIError:
+ plpy.warning("Caught a SPI error")
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_mix_explicit_and_implicit();
+WARNING: Caught a SPI error from an explicit subtransaction
+CONTEXT: PL/Python function "subtransaction_mix_explicit_and_implicit"
+WARNING: Caught a SPI error
+CONTEXT: PL/Python function "subtransaction_mix_explicit_and_implicit"
+ subtransaction_mix_explicit_and_implicit
+------------------------------------------
+
+(1 row)
+
+SELECT * FROM subtransaction_tbl;
+ i
+---
+ 1
+ 2
+(2 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Alternative method names for Python <2.6
+CREATE FUNCTION subtransaction_alternative_names() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.enter()
+s.exit(None, None, None)
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_alternative_names();
+ subtransaction_alternative_names
+----------------------------------
+
+(1 row)
+
+-- try/catch inside a subtransaction block
+CREATE FUNCTION try_catch_inside_subtransaction() RETURNS void
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('a')")
+ except plpy.SPIError:
+ plpy.notice("caught")
+$$ LANGUAGE plpythonu;
+SELECT try_catch_inside_subtransaction();
+NOTICE: caught
+CONTEXT: PL/Python function "try_catch_inside_subtransaction"
+ try_catch_inside_subtransaction
+---------------------------------
+
+(1 row)
+
+SELECT * FROM subtransaction_tbl;
+ i
+---
+ 1
+(1 row)
+
+TRUNCATE subtransaction_tbl;
+ALTER TABLE subtransaction_tbl ADD PRIMARY KEY (i);
+NOTICE: ALTER TABLE / ADD PRIMARY KEY will create implicit index "subtransaction_tbl_pkey" for table "subtransaction_tbl"
+CREATE FUNCTION pk_violation_inside_subtransaction() RETURNS void
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ except plpy.SPIError:
+ plpy.notice("caught")
+$$ LANGUAGE plpythonu;
+SELECT pk_violation_inside_subtransaction();
+NOTICE: caught
+CONTEXT: PL/Python function "pk_violation_inside_subtransaction"
+ pk_violation_inside_subtransaction
+------------------------------------
+
+(1 row)
+
+SELECT * FROM subtransaction_tbl;
+ i
+---
+ 1
+(1 row)
+
+DROP TABLE subtransaction_tbl;
--- /dev/null
+--
+-- Test explicit subtransactions
+--
+-- Test table to see if transactions get properly rolled back
+CREATE TABLE subtransaction_tbl (
+ i integer
+);
+-- Explicit case for Python <2.6
+CREATE FUNCTION subtransaction_test(what_error text = NULL) RETURNS text
+AS $$
+import sys
+subxact = plpy.subtransaction()
+subxact.__enter__()
+exc = True
+try:
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ if what_error == "SPI":
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('oops')")
+ elif what_error == "Python":
+ plpy.attribute_error
+ except:
+ exc = False
+ subxact.__exit__(*sys.exc_info())
+ raise
+finally:
+ if exc:
+ subxact.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_test();
+ subtransaction_test
+---------------------
+
+(1 row)
+
+SELECT * FROM subtransaction_tbl;
+ i
+---
+ 1
+ 2
+(2 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_test('SPI');
+ERROR: plpy.SPIError: invalid input syntax for integer: "oops"
+LINE 1: INSERT INTO subtransaction_tbl VALUES ('oops')
+ ^
+QUERY: INSERT INTO subtransaction_tbl VALUES ('oops')
+CONTEXT: PL/Python function "subtransaction_test"
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_test('Python');
+ERROR: AttributeError: 'module' object has no attribute 'attribute_error'
+CONTEXT: PL/Python function "subtransaction_test"
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Context manager case for Python >=2.6
+CREATE FUNCTION subtransaction_ctx_test(what_error text = NULL) RETURNS text
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ if what_error == "SPI":
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('oops')")
+ elif what_error == "Python":
+ plpy.attribute_error
+$$ LANGUAGE plpythonu;
+ERROR: could not compile PL/Python function "subtransaction_ctx_test"
+DETAIL: SyntaxError: invalid syntax (line 3)
+SELECT subtransaction_ctx_test();
+ERROR: function subtransaction_ctx_test() does not exist
+LINE 1: SELECT subtransaction_ctx_test();
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_ctx_test('SPI');
+ERROR: function subtransaction_ctx_test(unknown) does not exist
+LINE 1: SELECT subtransaction_ctx_test('SPI');
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_ctx_test('Python');
+ERROR: function subtransaction_ctx_test(unknown) does not exist
+LINE 1: SELECT subtransaction_ctx_test('Python');
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Nested subtransactions
+CREATE FUNCTION subtransaction_nested_test(swallow boolean = 'f') RETURNS text
+AS $$
+plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ try:
+ with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (3)")
+ plpy.execute("error")
+ except plpy.SPIError, e:
+ if not swallow:
+ raise
+ plpy.notice("Swallowed %r" % e)
+return "ok"
+$$ LANGUAGE plpythonu;
+ERROR: could not compile PL/Python function "subtransaction_nested_test"
+DETAIL: SyntaxError: invalid syntax (line 4)
+SELECT subtransaction_nested_test();
+ERROR: function subtransaction_nested_test() does not exist
+LINE 1: SELECT subtransaction_nested_test();
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_nested_test('t');
+ERROR: function subtransaction_nested_test(unknown) does not exist
+LINE 1: SELECT subtransaction_nested_test('t');
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Nested subtransactions that recursively call code dealing with
+-- subtransactions
+CREATE FUNCTION subtransaction_deeply_nested_test() RETURNS text
+AS $$
+plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ plpy.execute("SELECT subtransaction_nested_test('t')")
+return "ok"
+$$ LANGUAGE plpythonu;
+ERROR: could not compile PL/Python function "subtransaction_deeply_nested_test"
+DETAIL: SyntaxError: invalid syntax (line 4)
+SELECT subtransaction_deeply_nested_test();
+ERROR: function subtransaction_deeply_nested_test() does not exist
+LINE 1: SELECT subtransaction_deeply_nested_test();
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Error conditions from not opening/closing subtransactions
+CREATE FUNCTION subtransaction_exit_without_enter() RETURNS void
+AS $$
+plpy.subtransaction().__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_enter_without_exit() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_exit_twice() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+plpy.subtransaction().__exit__(None, None, None)
+plpy.subtransaction().__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_enter_twice() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+plpy.subtransaction().__enter__()
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_exit_same_subtransaction_twice() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.__enter__()
+s.__exit__(None, None, None)
+s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+CREATE FUNCTION subtransaction_enter_same_subtransaction_twice() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.__enter__()
+s.__enter__()
+s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+-- No warnings here, as the subtransaction gets indeed closed
+CREATE FUNCTION subtransaction_enter_subtransaction_in_with() RETURNS void
+AS $$
+with plpy.subtransaction() as s:
+ s.__enter__()
+$$ LANGUAGE plpythonu;
+ERROR: could not compile PL/Python function "subtransaction_enter_subtransaction_in_with"
+DETAIL: SyntaxError: invalid syntax (line 3)
+CREATE FUNCTION subtransaction_exit_subtransaction_in_with() RETURNS void
+AS $$
+with plpy.subtransaction() as s:
+ s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+ERROR: could not compile PL/Python function "subtransaction_exit_subtransaction_in_with"
+DETAIL: SyntaxError: invalid syntax (line 3)
+SELECT subtransaction_exit_without_enter();
+ERROR: ValueError: this subtransaction has not been entered
+CONTEXT: PL/Python function "subtransaction_exit_without_enter"
+SELECT subtransaction_enter_without_exit();
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_enter_without_exit"
+ subtransaction_enter_without_exit
+-----------------------------------
+
+(1 row)
+
+SELECT subtransaction_exit_twice();
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_exit_twice"
+ERROR: ValueError: this subtransaction has not been entered
+CONTEXT: PL/Python function "subtransaction_exit_twice"
+SELECT subtransaction_enter_twice();
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_enter_twice"
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_enter_twice"
+ subtransaction_enter_twice
+----------------------------
+
+(1 row)
+
+SELECT subtransaction_exit_same_subtransaction_twice();
+ERROR: ValueError: this subtransaction has already been exited
+CONTEXT: PL/Python function "subtransaction_exit_same_subtransaction_twice"
+SELECT subtransaction_enter_same_subtransaction_twice();
+WARNING: forcibly aborting a subtransaction that has not been exited
+CONTEXT: PL/Python function "subtransaction_enter_same_subtransaction_twice"
+ERROR: ValueError: this subtransaction has already been entered
+CONTEXT: PL/Python function "subtransaction_enter_same_subtransaction_twice"
+SELECT subtransaction_enter_subtransaction_in_with();
+ERROR: function subtransaction_enter_subtransaction_in_with() does not exist
+LINE 1: SELECT subtransaction_enter_subtransaction_in_with();
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT subtransaction_exit_subtransaction_in_with();
+ERROR: function subtransaction_exit_subtransaction_in_with() does not exist
+LINE 1: SELECT subtransaction_exit_subtransaction_in_with();
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+-- Make sure we don't get a "current transaction is aborted" error
+SELECT 1 as test;
+ test
+------
+ 1
+(1 row)
+
+-- Mix explicit subtransactions and normal SPI calls
+CREATE FUNCTION subtransaction_mix_explicit_and_implicit() RETURNS void
+AS $$
+p = plpy.prepare("INSERT INTO subtransaction_tbl VALUES ($1)", ["integer"])
+try:
+ with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute(p, [2])
+ plpy.execute(p, ["wrong"])
+except plpy.SPIError:
+ plpy.warning("Caught a SPI error from an explicit subtransaction")
+
+try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute(p, [2])
+ plpy.execute(p, ["wrong"])
+except plpy.SPIError:
+ plpy.warning("Caught a SPI error")
+$$ LANGUAGE plpythonu;
+ERROR: could not compile PL/Python function "subtransaction_mix_explicit_and_implicit"
+DETAIL: SyntaxError: invalid syntax (line 5)
+SELECT subtransaction_mix_explicit_and_implicit();
+ERROR: function subtransaction_mix_explicit_and_implicit() does not exist
+LINE 1: SELECT subtransaction_mix_explicit_and_implicit();
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+-- Alternative method names for Python <2.6
+CREATE FUNCTION subtransaction_alternative_names() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.enter()
+s.exit(None, None, None)
+$$ LANGUAGE plpythonu;
+SELECT subtransaction_alternative_names();
+ subtransaction_alternative_names
+----------------------------------
+
+(1 row)
+
+-- try/catch inside a subtransaction block
+CREATE FUNCTION try_catch_inside_subtransaction() RETURNS void
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('a')")
+ except plpy.SPIError:
+ plpy.notice("caught")
+$$ LANGUAGE plpythonu;
+ERROR: could not compile PL/Python function "try_catch_inside_subtransaction"
+DETAIL: SyntaxError: invalid syntax (line 3)
+SELECT try_catch_inside_subtransaction();
+ERROR: function try_catch_inside_subtransaction() does not exist
+LINE 1: SELECT try_catch_inside_subtransaction();
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+TRUNCATE subtransaction_tbl;
+ALTER TABLE subtransaction_tbl ADD PRIMARY KEY (i);
+NOTICE: ALTER TABLE / ADD PRIMARY KEY will create implicit index "subtransaction_tbl_pkey" for table "subtransaction_tbl"
+CREATE FUNCTION pk_violation_inside_subtransaction() RETURNS void
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ except plpy.SPIError:
+ plpy.notice("caught")
+$$ LANGUAGE plpythonu;
+ERROR: could not compile PL/Python function "pk_violation_inside_subtransaction"
+DETAIL: SyntaxError: invalid syntax (line 3)
+SELECT pk_violation_inside_subtransaction();
+ERROR: function pk_violation_inside_subtransaction() does not exist
+LINE 1: SELECT pk_violation_inside_subtransaction();
+ ^
+HINT: No function matches the given name and argument types. You might need to add explicit type casts.
+SELECT * FROM subtransaction_tbl;
+ i
+---
+(0 rows)
+
+DROP TABLE subtransaction_tbl;
return ", ".join(contents)
$$ LANGUAGE plpythonu;
select module_contents();
- module_contents
----------------------------------------------------------------------------------------------------------------------------------------
- Error, Fatal, SPIError, debug, error, execute, fatal, info, log, notice, prepare, quote_ident, quote_literal, quote_nullable, warning
+ module_contents
+-------------------------------------------------------------------------------------------------------------------------------------------------------
+ Error, Fatal, SPIError, debug, error, execute, fatal, info, log, notice, prepare, quote_ident, quote_literal, quote_nullable, subtransaction, warning
(1 row)
CREATE FUNCTION elog_test() RETURNS void
PLyProcedure *proc;
} PLyProcedureEntry;
+/* explicit subtransaction data */
+typedef struct PLySubtransactionData
+{
+ MemoryContext oldcontext;
+ ResourceOwner oldowner;
+} PLySubtransactionData;
+
/* Python objects */
typedef struct PLyPlanObject
PyObject *status; /* query status, SPI_OK_*, or SPI_ERR_* */
} PLyResultObject;
+typedef struct PLySubtransactionObject
+{
+ PyObject_HEAD
+ bool started;
+ bool exited;
+} PLySubtransactionObject;
+
/* function declarations */
*/
static PLyProcedure *PLy_curr_procedure = NULL;
+/* list of explicit subtransaction data */
+static List *explicit_subtransactions = NIL;
+
static PyObject *PLy_interp_globals = NULL;
static PyObject *PLy_interp_safe_globals = NULL;
static HTAB *PLy_procedure_cache = NULL;
"Results of a PostgreSQL query"
};
+static char PLy_subtransaction_doc[] = {
+ "PostgreSQL subtransaction context manager"
+};
+
/*
* the function definitions
return rv;
}
+/*
+ * Abort lingering subtransactions that have been explicitly started
+ * by plpy.subtransaction().start() and not properly closed.
+ */
+static void
+PLy_abort_open_subtransactions(int save_subxact_level)
+{
+ Assert(save_subxact_level >= 0);
+
+ while (list_length(explicit_subtransactions) > save_subxact_level)
+ {
+ PLySubtransactionData *subtransactiondata;
+
+ Assert(explicit_subtransactions != NIL);
+
+ ereport(WARNING,
+ (errmsg("forcibly aborting a subtransaction that has not been exited")));
+
+ RollbackAndReleaseCurrentSubTransaction();
+
+ SPI_restore_connection();
+
+ subtransactiondata = (PLySubtransactionData *) linitial(explicit_subtransactions);
+ explicit_subtransactions = list_delete_first(explicit_subtransactions);
+
+ MemoryContextSwitchTo(subtransactiondata->oldcontext);
+ CurrentResourceOwner = subtransactiondata->oldowner;
+ PLy_free(subtransactiondata);
+ }
+}
+
static PyObject *
PLy_procedure_call(PLyProcedure *proc, char *kargs, PyObject *vargs)
{
PyObject *rv;
+ int volatile save_subxact_level = list_length(explicit_subtransactions);
PyDict_SetItemString(proc->globals, kargs, vargs);
+
+ PG_TRY();
+ {
#if PY_VERSION_HEX >= 0x03020000
- rv = PyEval_EvalCode(proc->code,
- proc->globals, proc->globals);
+ rv = PyEval_EvalCode(proc->code,
+ proc->globals, proc->globals);
#else
- rv = PyEval_EvalCode((PyCodeObject *) proc->code,
- proc->globals, proc->globals);
+ rv = PyEval_EvalCode((PyCodeObject *) proc->code,
+ proc->globals, proc->globals);
#endif
+ /*
+ * Since plpy will only let you close subtransactions that
+ * you started, you cannot *unnest* subtransactions, only
+ * *nest* them without closing.
+ */
+ Assert(list_length(explicit_subtransactions) >= save_subxact_level);
+ }
+ PG_CATCH();
+ {
+ PLy_abort_open_subtransactions(save_subxact_level);
+ PG_RE_THROW();
+ }
+ PG_END_TRY();
+
+ PLy_abort_open_subtransactions(save_subxact_level);
+
/* If the Python code returned an error, propagate it */
if (rv == NULL)
PLy_elog(ERROR, NULL);
static PyObject *PLy_quote_nullable(PyObject *self, PyObject *args);
static PyObject *PLy_quote_ident(PyObject *self, PyObject *args);
+static PyObject *PLy_subtransaction(PyObject *, PyObject *);
+static PyObject *PLy_subtransaction_new(void);
+static void PLy_subtransaction_dealloc(PyObject *);
+static PyObject *PLy_subtransaction_enter(PyObject *, PyObject *);
+static PyObject *PLy_subtransaction_exit(PyObject *, PyObject *);
+
static PyMethodDef PLy_plan_methods[] = {
{"status", PLy_plan_status, METH_VARARGS, NULL},
PLy_result_methods, /* tp_tpmethods */
};
+static PyMethodDef PLy_subtransaction_methods[] = {
+ {"__enter__", PLy_subtransaction_enter, METH_VARARGS, NULL},
+ {"__exit__", PLy_subtransaction_exit, METH_VARARGS, NULL},
+ /* user-friendly names for Python <2.6 */
+ {"enter", PLy_subtransaction_enter, METH_VARARGS, NULL},
+ {"exit", PLy_subtransaction_exit, METH_VARARGS, NULL},
+ {NULL, NULL, 0, NULL}
+};
+
+static PyTypeObject PLy_SubtransactionType = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ "PLySubtransaction", /* tp_name */
+ sizeof(PLySubtransactionObject), /* tp_size */
+ 0, /* tp_itemsize */
+
+ /*
+ * methods
+ */
+ PLy_subtransaction_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_compare */
+ 0, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ 0, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+ PLy_subtransaction_doc, /* tp_doc */
+ 0, /* tp_traverse */
+ 0, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ 0, /* tp_iter */
+ 0, /* tp_iternext */
+ PLy_subtransaction_methods, /* tp_tpmethods */
+};
+
static PyMethodDef PLy_methods[] = {
/*
* logging methods
{"quote_nullable", PLy_quote_nullable, METH_VARARGS, NULL},
{"quote_ident", PLy_quote_ident, METH_VARARGS, NULL},
+ /*
+ * create the subtransaction context manager
+ */
+ {"subtransaction", PLy_subtransaction, METH_NOARGS, NULL},
+
{NULL, NULL, 0, NULL}
};
return (PyObject *) result;
}
+/* s = plpy.subtransaction() */
+static PyObject *
+PLy_subtransaction(PyObject *self, PyObject *unused)
+{
+ return PLy_subtransaction_new();
+}
+
+/* Allocate and initialize a PLySubtransactionObject */
+static PyObject *
+PLy_subtransaction_new(void)
+{
+ PLySubtransactionObject *ob;
+
+ ob = PyObject_New(PLySubtransactionObject, &PLy_SubtransactionType);
+
+ if (ob == NULL)
+ return NULL;
+
+ ob->started = false;
+ ob->exited = false;
+
+ return (PyObject *) ob;
+}
+
+/* Python requires a dealloc function to be defined */
+static void
+PLy_subtransaction_dealloc(PyObject *subxact)
+{
+}
+
+/*
+ * subxact.__enter__() or subxact.enter()
+ *
+ * Start an explicit subtransaction. SPI calls within an explicit
+ * subtransaction will not start another one, so you can atomically
+ * execute many SPI calls and still get a controllable exception if
+ * one of them fails.
+ */
+static PyObject *
+PLy_subtransaction_enter(PyObject *self, PyObject *unused)
+{
+ PLySubtransactionData *subxactdata;
+ MemoryContext oldcontext;
+ PLySubtransactionObject *subxact = (PLySubtransactionObject *) self;
+
+ if (subxact->started)
+ {
+ PLy_exception_set(PyExc_ValueError, "this subtransaction has already been entered");
+ return NULL;
+ }
+
+ if (subxact->exited)
+ {
+ PLy_exception_set(PyExc_ValueError, "this subtransaction has already been exited");
+ return NULL;
+ }
+
+ subxact->started = true;
+ oldcontext = CurrentMemoryContext;
+
+ subxactdata = PLy_malloc(sizeof(*subxactdata));
+ subxactdata->oldcontext = oldcontext;
+ subxactdata->oldowner = CurrentResourceOwner;
+
+ BeginInternalSubTransaction(NULL);
+ /* Do not want to leave the previous memory context */
+ MemoryContextSwitchTo(oldcontext);
+
+ explicit_subtransactions = lcons(subxactdata, explicit_subtransactions);
+
+ Py_INCREF(self);
+ return self;
+}
+
+/*
+ * subxact.__exit__(exc_type, exc, tb) or subxact.exit(exc_type, exc, tb)
+ *
+ * Exit an explicit subtransaction. exc_type is an exception type, exc
+ * is the exception object, tb is the traceback. If exc_type is None,
+ * commit the subtransactiony, if not abort it.
+ *
+ * The method signature is chosen to allow subtransaction objects to
+ * be used as context managers as described in
+ * <http://www.python.org/dev/peps/pep-0343/>.
+ */
+static PyObject *
+PLy_subtransaction_exit(PyObject *self, PyObject *args)
+{
+ PyObject *type;
+ PyObject *value;
+ PyObject *traceback;
+ PLySubtransactionData *subxactdata;
+ PLySubtransactionObject *subxact = (PLySubtransactionObject *) self;
+
+ if (!PyArg_ParseTuple(args, "OOO", &type, &value, &traceback))
+ return NULL;
+
+ if (!subxact->started)
+ {
+ PLy_exception_set(PyExc_ValueError, "this subtransaction has not been entered");
+ return NULL;
+ }
+
+ if (subxact->exited)
+ {
+ PLy_exception_set(PyExc_ValueError, "this subtransaction has already been exited");
+ return NULL;
+ }
+
+ if (explicit_subtransactions == NIL)
+ {
+ PLy_exception_set(PyExc_ValueError, "there is no subtransaction to exit from");
+ return NULL;
+ }
+
+ subxact->exited = true;
+
+ if (type != Py_None)
+ {
+ /* Abort the inner transaction */
+ RollbackAndReleaseCurrentSubTransaction();
+ }
+ else
+ {
+ ReleaseCurrentSubTransaction();
+ }
+
+ subxactdata = (PLySubtransactionData *) linitial(explicit_subtransactions);
+ explicit_subtransactions = list_delete_first(explicit_subtransactions);
+
+ MemoryContextSwitchTo(subxactdata->oldcontext);
+ CurrentResourceOwner = subxactdata->oldowner;
+ PLy_free(subxactdata);
+
+ /*
+ * AtEOSubXact_SPI() should not have popped any SPI context, but
+ * just in case it did, make sure we remain connected.
+ */
+ SPI_restore_connection();
+
+ Py_INCREF(Py_None);
+ return Py_None;
+}
+
/*
* language handler and interpreter initialization
PLy_trigger_cache = hash_create("PL/Python triggers", 32, &hash_ctl,
HASH_ELEM | HASH_FUNCTION);
+ explicit_subtransactions = NIL;
+
inited = true;
}
elog(ERROR, "could not initialize PLy_PlanType");
if (PyType_Ready(&PLy_ResultType) < 0)
elog(ERROR, "could not initialize PLy_ResultType");
+ if (PyType_Ready(&PLy_SubtransactionType) < 0)
+ elog(ERROR, "could not initialize PLy_SubtransactionType");
#if PY_MAJOR_VERSION >= 3
plpy = PyModule_Create(&PLy_module);
--- /dev/null
+--
+-- Test explicit subtransactions
+--
+
+-- Test table to see if transactions get properly rolled back
+
+CREATE TABLE subtransaction_tbl (
+ i integer
+);
+
+-- Explicit case for Python <2.6
+
+CREATE FUNCTION subtransaction_test(what_error text = NULL) RETURNS text
+AS $$
+import sys
+subxact = plpy.subtransaction()
+subxact.__enter__()
+exc = True
+try:
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ if what_error == "SPI":
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('oops')")
+ elif what_error == "Python":
+ plpy.attribute_error
+ except:
+ exc = False
+ subxact.__exit__(*sys.exc_info())
+ raise
+finally:
+ if exc:
+ subxact.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+
+SELECT subtransaction_test();
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_test('SPI');
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_test('Python');
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+
+-- Context manager case for Python >=2.6
+
+CREATE FUNCTION subtransaction_ctx_test(what_error text = NULL) RETURNS text
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ if what_error == "SPI":
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('oops')")
+ elif what_error == "Python":
+ plpy.attribute_error
+$$ LANGUAGE plpythonu;
+
+SELECT subtransaction_ctx_test();
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_ctx_test('SPI');
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+SELECT subtransaction_ctx_test('Python');
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+
+-- Nested subtransactions
+
+CREATE FUNCTION subtransaction_nested_test(swallow boolean = 'f') RETURNS text
+AS $$
+plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ try:
+ with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (3)")
+ plpy.execute("error")
+ except plpy.SPIError, e:
+ if not swallow:
+ raise
+ plpy.notice("Swallowed %r" % e)
+return "ok"
+$$ LANGUAGE plpythonu;
+
+SELECT subtransaction_nested_test();
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+
+SELECT subtransaction_nested_test('t');
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+
+-- Nested subtransactions that recursively call code dealing with
+-- subtransactions
+
+CREATE FUNCTION subtransaction_deeply_nested_test() RETURNS text
+AS $$
+plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (2)")
+ plpy.execute("SELECT subtransaction_nested_test('t')")
+return "ok"
+$$ LANGUAGE plpythonu;
+
+SELECT subtransaction_deeply_nested_test();
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+
+-- Error conditions from not opening/closing subtransactions
+
+CREATE FUNCTION subtransaction_exit_without_enter() RETURNS void
+AS $$
+plpy.subtransaction().__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+
+CREATE FUNCTION subtransaction_enter_without_exit() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+$$ LANGUAGE plpythonu;
+
+CREATE FUNCTION subtransaction_exit_twice() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+plpy.subtransaction().__exit__(None, None, None)
+plpy.subtransaction().__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+
+CREATE FUNCTION subtransaction_enter_twice() RETURNS void
+AS $$
+plpy.subtransaction().__enter__()
+plpy.subtransaction().__enter__()
+$$ LANGUAGE plpythonu;
+
+CREATE FUNCTION subtransaction_exit_same_subtransaction_twice() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.__enter__()
+s.__exit__(None, None, None)
+s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+
+CREATE FUNCTION subtransaction_enter_same_subtransaction_twice() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.__enter__()
+s.__enter__()
+s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+
+-- No warnings here, as the subtransaction gets indeed closed
+CREATE FUNCTION subtransaction_enter_subtransaction_in_with() RETURNS void
+AS $$
+with plpy.subtransaction() as s:
+ s.__enter__()
+$$ LANGUAGE plpythonu;
+
+CREATE FUNCTION subtransaction_exit_subtransaction_in_with() RETURNS void
+AS $$
+with plpy.subtransaction() as s:
+ s.__exit__(None, None, None)
+$$ LANGUAGE plpythonu;
+
+SELECT subtransaction_exit_without_enter();
+SELECT subtransaction_enter_without_exit();
+SELECT subtransaction_exit_twice();
+SELECT subtransaction_enter_twice();
+SELECT subtransaction_exit_same_subtransaction_twice();
+SELECT subtransaction_enter_same_subtransaction_twice();
+SELECT subtransaction_enter_subtransaction_in_with();
+SELECT subtransaction_exit_subtransaction_in_with();
+
+-- Make sure we don't get a "current transaction is aborted" error
+SELECT 1 as test;
+
+-- Mix explicit subtransactions and normal SPI calls
+
+CREATE FUNCTION subtransaction_mix_explicit_and_implicit() RETURNS void
+AS $$
+p = plpy.prepare("INSERT INTO subtransaction_tbl VALUES ($1)", ["integer"])
+try:
+ with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute(p, [2])
+ plpy.execute(p, ["wrong"])
+except plpy.SPIError:
+ plpy.warning("Caught a SPI error from an explicit subtransaction")
+
+try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ plpy.execute(p, [2])
+ plpy.execute(p, ["wrong"])
+except plpy.SPIError:
+ plpy.warning("Caught a SPI error")
+$$ LANGUAGE plpythonu;
+
+SELECT subtransaction_mix_explicit_and_implicit();
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+
+-- Alternative method names for Python <2.6
+
+CREATE FUNCTION subtransaction_alternative_names() RETURNS void
+AS $$
+s = plpy.subtransaction()
+s.enter()
+s.exit(None, None, None)
+$$ LANGUAGE plpythonu;
+
+SELECT subtransaction_alternative_names();
+
+-- try/catch inside a subtransaction block
+
+CREATE FUNCTION try_catch_inside_subtransaction() RETURNS void
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES ('a')")
+ except plpy.SPIError:
+ plpy.notice("caught")
+$$ LANGUAGE plpythonu;
+
+SELECT try_catch_inside_subtransaction();
+SELECT * FROM subtransaction_tbl;
+TRUNCATE subtransaction_tbl;
+
+ALTER TABLE subtransaction_tbl ADD PRIMARY KEY (i);
+
+CREATE FUNCTION pk_violation_inside_subtransaction() RETURNS void
+AS $$
+with plpy.subtransaction():
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ try:
+ plpy.execute("INSERT INTO subtransaction_tbl VALUES (1)")
+ except plpy.SPIError:
+ plpy.notice("caught")
+$$ LANGUAGE plpythonu;
+
+SELECT pk_violation_inside_subtransaction();
+SELECT * FROM subtransaction_tbl;
+
+DROP TABLE subtransaction_tbl;
OSDN Git Service
