Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit402da70

Browse files
committed
Initialize random() in bootstrap/stand-alone postgres and in initdb.
This removes a difference between the standard IsUnderPostmasterexecution environment and that of --boot and --single. In a stand-alonebackend, "SELECT random()" always started at the same seed.On a system capable of using posix shared memory, initdb could stillconclude "selecting dynamic shared memory implementation ... sysv".Crashed --boot or --single postgres processes orphaned shared memoryobjects having names that collided with the not-actually-random namesthat initdb probed. The sysv fallback appeared after ten crashes of--boot or --single postgres. Since --boot and --single are rare inproduction use, systems used for PostgreSQL development are theprincipal candidate to notice this symptom.Back-patch to 9.3 (all supported versions). PostgreSQL 9.4 introduceddynamic shared memory, but 9.3 does share the "SELECT random()" problem.Reviewed by Tom Lane and Kyotaro HORIGUCHI.Discussion:https://postgr.es/m/20180915221546.GA3159382@rfd.leadboat.com
1 parent00011a6 commit402da70

File tree

2 files changed

+16
-0
lines changed

2 files changed

+16
-0
lines changed

‎src/backend/bootstrap/bootstrap.c

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -202,6 +202,14 @@ AuxiliaryProcessMain(int argc, char *argv[])
202202

203203
MyStartTime=time(NULL);
204204

205+
/*
206+
* Initialize random() for the first time, like PostmasterMain() would.
207+
* In a regular IsUnderPostmaster backend, BackendRun() computes a
208+
* high-entropy seed before any user query. Fewer distinct initial seeds
209+
* can occur here.
210+
*/
211+
srandom((unsignedint) (MyProcPid ^MyStartTime));
212+
205213
/* Compute paths, if we didn't inherit them from postmaster */
206214
if (my_exec_path[0]=='\0')
207215
{

‎src/backend/tcop/postgres.c

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3620,6 +3620,14 @@ PostgresMain(int argc, char *argv[],
36203620
MyProcPid=getpid();
36213621

36223622
MyStartTime=time(NULL);
3623+
3624+
/*
3625+
* Initialize random() for the first time, like PostmasterMain()
3626+
* would. In a regular IsUnderPostmaster backend, BackendRun()
3627+
* computes a high-entropy seed before any user query. Fewer distinct
3628+
* initial seeds can occur here.
3629+
*/
3630+
srandom((unsignedint) (MyProcPid ^MyStartTime));
36233631
}
36243632

36253633
SetProcessingMode(InitProcessing);

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp