pg.ddx.io pgsql-hackers@postgresql.org mailing list archive help / color / mirror / Atom feed From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mark Dilger <mark.dilger@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Peter Geoghegan <pg@bowt.ie>
Cc: Andrey M. Borodin <x4mmm@yandex-team.ru>
Cc: Stephen Frost <sfrost@snowman.net>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: Amul Sul <sulamul@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: new heapcheck contrib module
Date: Thu, 22 Oct 2020 16:23:36 -0400
Message-ID: <41306.1603398216@sss.pgh.pa.us> (raw )
In-Reply-To: <E9FB76F8-DF5A-4A37-BB7F-003E2626F336@enterprisedb.com >
References: <12ED3DA8-25F0-4B68-937D-D907CFBF08E7@enterprisedb.com >
<20200420194210.sevnpi4lyghoanxi@alap3.anarazel.de >
<23E60C3C-C20A-4508-84AC-E0CEA59E784A@enterprisedb.com >
<CA+TgmobAm8vB1MNQ1taO1et+HxTN8ULnQvEG+grNDqNQTBjbtA@mail.gmail.com >
<F845AC50-A479-43F3-ADFB-861A4D2AD287@enterprisedb.com >
<5F743835-3399-419C-8324-2D424237E999@enterprisedb.com >
<CAFiTN-syyHc3jZoou51v0SR8z0POoNfktqEO6MaGig4YS8mosA@mail.gmail.com >
<E6F4258A-B661-4F2C-8A35-278C9436930A@enterprisedb.com >
<CAFiTN-s-VX3DLfqv7OOo0zGCTOZ3xVU9UZ6GgzBZdJTPNnYFNg@mail.gmail.com >
<885D2EC9-7D06-4903-A17D-72C184A1E1C5@enterprisedb.com >
<CAFiTN-uYg_PiZ854=5R-D9skratapAHKhaDAG7fhJv-Vn5UhaQ@mail.gmail.com >
<5CC85F28-F210-47AC-8DA8-EC4E82AF3FD5@enterprisedb.com >
<CAFiTN-sP5iFJGERTq4a4OLTCzjZKhLC5P6_k2bxQKXnuvdmzGA@mail.gmail.com >
<CAFiTN-tTg0R5AHvXC1ro9XphroX1wUtc5t91hU_+7DeGTpE5VQ@mail.gmail.com >
<0C0349EB-DD85-4DA8-82C7-DF70AB714592@enterprisedb.com >
<BA6E870F-241C-4DDB-B92D-DB39E679C7D4@enterprisedb.com >
<CA+Tgm! obQUdfM2Q7WAR606RR2YehCZ5GHRKBc-VWfRj-1ZUKqDA@mail.gmail.com >
<C4A3E5AE-CBB2-4E3F-8BAE-29EE216762C2@enterprisedb.com >
<CAAJ_b96_Xr2a+D0j8xKbOnCzURcVQm0V2DS+T_pfc+wt3BpL8g@mail.gmail.com >
<9DF93B83-FE46-4EC4-A99D-77A60729FD2D@enterprisedb.com >
<CA+TgmoZT3kCOaKq6=m5wHGKh_9XQDbCC1LZXL6w_+NMB-n1+mw@mail.gmail.com >
<CAAJ_b94hsrF4x7UKQj03416fAEXJorUpZ9WhsZZjqgv-4+Wg9A@mail.gmail.com >
<50F6468F-5A5E-412A-86EC-DF24B549D733@enterprisedb.com >
<CAAJ_b94+A1Gk5r5sBYbYM2K5hH_gyp_o=+gwJuJhn5ZEm5_rqw@mail.gmail.com >
<CAAJ_b94Wh_7kM9JuJk7wnNsYSNPdSzz35cOEaE_ZRnPcqvupCg@mail.gmail.com >
<7D603B53-8078-4AF0-851B-803FF4416501@enterprisedb.com >
<CA+TgmoZbPtTgkQBGoco39uqKUWuv=0+TOkiNcCuqWWvUkJVuxQ@mail.gmail.com >
<A4C9E0AE-46BA-457F-A445-4527E5AA5E3C@enterprisedb.com >
<98265AA9-7BDC-4708-9348-CC1B173BBE1D@enterprisedb.com >
<CA+Tgmoam+pnGKhWS+RAYCk1eqjhbAPX7Vm69g1VF56xwyxXw+g@mail.gmail.com >
<209783.1603313248@sss.pgh.pa.us >
<77A60E99-6054-40FD-A5D6-769C287D4A0F@enterprisedb.com >
<CA+TgmoaD5K6UhO2! zddxVCDY2TcR9wSLVurhQYAYpQ0VZPec0og@mail.gmail.com >
<CA+TgmobGxdm8Tsxawt7LW-qigHRHxD+b17PC+ft9EE+6pMhC9w@mail.gmail.com >
<721BFA83-EA6F-463D-A9DF-CE78A318B73A@enterprisedb.com >
<2A7DA1A8-C4AA-43DF-A985-3CA52F4DC775@enterprisedb.com >
<CA+TgmoaAG0BVk4b6iOYNCeALQ+4DGLmCbqYXqumK1noGq8UpnA@mail.gmail.com >
... btw, having now looked more closely at get_xid_status(), I wonder
how come there aren't more compilers bitching about it, because it
is very very obviously broken. In particular, the case of
requesting status for an xid that is BootstrapTransactionId or
FrozenTransactionId *will* fall through to perform
FullTransactionIdPrecedesOrEquals with an uninitialized fxid.
The fact that most compilers seem to fail to notice that is quite scary.
I suppose it has something to do with FullTransactionId being a struct,
which makes me wonder if that choice was quite as wise as we thought.
Meanwhile, so far as this code goes, I wonder why you don't just change it
to always set that value, ie
XidBoundsViolation result;
FullTransactionId fxid;
FullTransactionId clog_horizon;
+ fxid = FullTransactionIdFromXidAndCtx(xid, ctx);
+
/* Quick check for special xids */
if (!TransactionIdIsValid(xid))
result = XID_INVALID;
else if (xid == BootstrapTransactionId || xid == FrozenTransactionId)
result = XID_BOUNDS_OK;
else
{
/* Check if the xid is within bounds */
- fxid = FullTransactionIdFromXidAndCtx(xid, ctx);
if (!fxid_in_cached_range(fxid, ctx))
{
regards, tom lane
view thread (218+ messages) latest in thread
Message-ID: <41306.1603398216@sss.pgh.pa.us>
Permalink: ../41306.1603398216@sss.pgh.pa.us/
Also on: postgresql.org/message-id/41306.1603398216@sss.pgh.pa.us
copy link · copy postgr.es
reply Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, mark.dilger@enterprisedb.com, robertmhaas@gmail.com, pg@bowt.ie, x4mmm@yandex-team.ru, sfrost@snowman.net, michael@paquier.xyz, sulamul@gmail.com, dilipbalaut@gmail.com, andres@anarazel.de
Subject: Re: new heapcheck contrib module
In-Reply-To: <41306.1603398216@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox