In fact it doesn't change "the transaction", as there has to be no
transaction when invoked. The effect instead is to execute SET SESSION
CHARACTERISTICS.
The encoding can be set by PGCLIENTENCODING, which may be an alternative
spelling. Bug reported by Peter Eisentraut.
At this point the idea of considering one of the random spellings such as
EUC_CN as somewhat "blessed" is debunked. So just store the cleaned-up
version of the encoding in the mapping table. Note that the cleaned-up
version was needed by the unicode adapter: this requirement has been
surpassed as the connection now contains a copy of the Python codec name
set whenever the client encoding is set.
PG 9.0 uses the hex format by default, and clients < 9.0 can't parse that
format, requiring client update and great care in what is linked at runtime,
and generally giving headache to users and transitively us.
Looks like there is a case for installing hstore somewhere else (see
ticket #45). And after all the typecaster can be registered on a list of
OIDs, so let's grab them all.
Empty array can be returned untyped by postgres. To handle
this case, a special handler is added for the type UNKNOWNOID.
If the value return by the database is strictly equal to "{}",
the value is converted. Otherwise, the conversion fallback on
the default handler.
- Raise an exception on incomplete placeholders.
- Minor speedups.
- Don't change the string in place (??!!) if the placeholder is not s
and the value is null.
The latter point can be done because downstream we don't accept anything
different from s anyway (in the Bytes_Format function).
Notice that now the format string is constant whatever the arguments.
This means that executemany is still more inefficient than it should be
as mogrify may work only on the parameters. However this is an
implementation only worthwhile if we start supporting real parameters.
Let's talk about that for the next release.
The value is used to control the number of records to fetch per network
roundtrip in named cursors iteration. Used to avoid the inefficient
arraysize default of 1 without giving this value the magic meaning of
2000.
The feature in itself is not extremely useful and instead PostgreSQL is
not always able to cast away from text[], which is a regression see
(ticket #42).
