postgresql/src/backend/libpq
Michael Paquier 9e98583898 Create routine able to set single-call SRFs for Materialize mode
Set-returning functions that use the Materialize mode, creating a
tuplestore to include all the tuples returned in a set rather than doing
so in multiple calls, use roughly the same set of steps to prepare
ReturnSetInfo for this job:
- Check if ReturnSetInfo supports returning a tuplestore and if the
materialize mode is enabled.
- Create a tuplestore for all the tuples part of the returned set in the
per-query memory context, stored in ReturnSetInfo->setResult.
- Build a tuple descriptor mostly from get_call_result_type(), then
stored in ReturnSetInfo->setDesc.  Note that there are some cases where
the SRF's tuple descriptor has to be the one specified by the function
caller.

This refactoring is done so as there are (well, should be) no behavior
changes in any of the in-core functions refactored, and the centralized
function that checks and sets up the function's ReturnSetInfo can be
controlled with a set of bits32 options.  Two of them prove to be
necessary now:
- SRF_SINGLE_USE_EXPECTED to use expectedDesc as tuple descriptor, as
expected by the function's caller.
- SRF_SINGLE_BLESS to validate the tuple descriptor for the SRF.

The same initialization pattern is simplified in 28 places per my
count as of src/backend/, shaving up to ~900 lines of code.  These
mostly come from the removal of the per-query initializations and the
sanity checks now grouped in a single location.  There are more
locations that could be simplified in contrib/, that are left for a
follow-up cleanup.

fcc2817, 07daca5 and d61a361 have prepared the areas of the code related
to this change, to ease this refactoring.

Author: Melanie Plageman, Michael Paquier
Reviewed-by: Álvaro Herrera, Justin Pryzby
Discussion: https://postgr.es/m/CAAKRu_azyd1Z3W_r7Ou4sorTjRCs+PxeHw1CWJeXKofkE6TuZg@mail.gmail.com
2022-03-07 10:26:29 +09:00
..
Makefile Refactor SASL code with a generic interface for its mechanisms 2021-07-07 10:55:15 +09:00
README.SSL Move EDH support to common files 2018-01-23 07:11:38 -05:00
auth-sasl.c Improve error handling of cryptohash computations 2022-01-11 09:55:16 +09:00
auth-scram.c Improve error handling of HMAC computations 2022-01-13 16:17:21 +09:00
auth.c Clean up messy API for src/port/thread.c. 2022-01-11 13:46:20 -05:00
be-fsstubs.c Update copyright for 2022 2022-01-07 19:04:57 -05:00
be-gssapi-common.c Update copyright for 2022 2022-01-07 19:04:57 -05:00
be-secure-common.c Allow root-owned SSL private keys in libpq, not only the backend. 2022-02-28 14:12:52 -05:00
be-secure-gssapi.c Update copyright for 2022 2022-01-07 19:04:57 -05:00
be-secure-openssl.c Update copyright for 2022 2022-01-07 19:04:57 -05:00
be-secure.c Update copyright for 2022 2022-01-07 19:04:57 -05:00
crypt.c Improve error handling of cryptohash computations 2022-01-11 09:55:16 +09:00
hba.c Create routine able to set single-call SRFs for Materialize mode 2022-03-07 10:26:29 +09:00
ifaddr.c Update copyright for 2022 2022-01-07 19:04:57 -05:00
pg_hba.conf.sample pg_hba.conf.sample: Reword connection type section 2021-04-29 07:00:20 +02:00
pg_ident.conf.sample Reformat the comments in pg_hba.conf and pg_ident.conf 2010-01-26 06:58:39 +00:00
pqcomm.c Remove IS_AF_UNIX macro 2022-02-15 10:16:34 +01:00
pqformat.c Update copyright for 2022 2022-01-07 19:04:57 -05:00
pqmq.c Update copyright for 2022 2022-01-07 19:04:57 -05:00
pqsignal.c Update copyright for 2022 2022-01-07 19:04:57 -05:00

README.SSL

src/backend/libpq/README.SSL

SSL
===

>From the servers perspective:


  Receives StartupPacket
           |
           |
 (Is SSL_NEGOTIATE_CODE?) -----------  Normal startup
           |                  No
           |
           | Yes
           |
           |
 (Server compiled with USE_SSL?) ------- Send 'N'
           |                       No        |
           |                                 |
           | Yes                         Normal startup
           |
           |
        Send 'S'
           |
           |
      Establish SSL
           |
           |
      Normal startup





>From the clients perspective (v6.6 client _with_ SSL):


      Connect
         |
         |
  Send packet with SSL_NEGOTIATE_CODE
         |
         |
  Receive single char  ------- 'S' -------- Establish SSL
         |                                       |
         | '<else>'                              |
         |                                  Normal startup
         |
         |
   Is it 'E' for error  ------------------- Retry connection
         |                  Yes             without SSL
         | No
         |
   Is it 'N' for normal ------------------- Normal startup
         |                  Yes
         |
   Fail with unknown

---------------------------------------------------------------------------

Ephemeral DH
============

Since the server static private key ($DataDir/server.key) will
normally be stored unencrypted so that the database backend can
restart automatically, it is important that we select an algorithm
that continues to provide confidentiality even if the attacker has the
server's private key.  Ephemeral DH (EDH) keys provide this and more
(Perfect Forward Secrecy aka PFS).

N.B., the static private key should still be protected to the largest
extent possible, to minimize the risk of impersonations.

Another benefit of EDH is that it allows the backend and clients to
use DSA keys.  DSA keys can only provide digital signatures, not
encryption, and are often acceptable in jurisdictions where RSA keys
are unacceptable.

The downside to EDH is that it makes it impossible to use ssldump(1)
if there's a problem establishing an SSL session.  In this case you'll
need to temporarily disable EDH (see initialize_dh()).