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

Commitca71c66

Browse files
committed
Update FAQ.
1 parentbb1095c commitca71c66

File tree

2 files changed

+60
-22
lines changed

2 files changed

+60
-22
lines changed

‎doc/FAQ‎

Lines changed: 28 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -83,12 +83,14 @@
8383
other users?
8484
4.17) What is an OID? What is a TID?
8585
4.18) What is the meaning of some of the terms used in PostgreSQL?
86-
4.19) How do I tell what PostgreSQL version I am running?
87-
4.20) My large-object operations get invalid large obj descriptor.
86+
4.19) Why do I get the error "ERROR: Memory exhausted in
87+
AllocSetAlloc()?"
88+
4.20) How do I tell what PostgreSQL version I am running?
89+
4.21) My large-object operations get invalid large obj descriptor.
8890
Why?
89-
4.21) How do I create a column that will default to the current time?
90-
4.22) Why are my subqueries using IN so slow?
91-
4.23) How do I perform an outer join?
91+
4.22) How do I create a column that will default to the current time?
92+
4.23) Why are my subqueries using IN so slow?
93+
4.24) How do I perform an outer join?
9294

9395
Extending PostgreSQL
9496

@@ -97,7 +99,7 @@
9799
5.2) How can I contribute some nifty new types and functions to
98100
PostgreSQL?
99101
5.3) How do I write a C function to return a tuple?
100-
5.4) I have changed a source file. Why does the recompile not see the
102+
5.3) I have changed a source file. Why does the recompile not see the
101103
change?
102104
_________________________________________________________________
103105

@@ -883,11 +885,26 @@ BYTEA bytea variable-length byte array (null-safe)
883885
A list of general database terms can be found at:
884886
http://www.comptechnews.com/~reaster/dbdesign.html
885887

886-
4.19) How do I tell what PostgreSQL version I am running?
888+
4.19) Why do I get the error "ERROR: Memory exhausted in AllocSetAlloc()?"
889+
890+
It is possible you have run out of virtual memory on your system, or
891+
your kernel has a low limit for certain resources. Try this before
892+
starting the postmaster:
893+
ulimit -d 262144
894+
limit datasize 256m
895+
896+
Depending on your shell, only one of these may succeed, but it will
897+
set your process data segment limit much higher and perhaps allow the
898+
query to complete. This command applies to the current process, and
899+
all subprocesses created after the command is run. If you are having a
900+
problem with the SQL client because the backend is returning too much
901+
data, try it before starting the client.
902+
903+
4.20) How do I tell what PostgreSQL version I am running?
887904

888905
From psql, type select version();
889906

890-
4.20) My large-object operations get invalid large obj descriptor. Why?
907+
4.21) My large-object operations get invalid large obj descriptor. Why?
891908

892909
You need to put BEGIN WORK and COMMIT around any use of a large object
893910
handle, that is, surrounding lo_open ... lo_close.
@@ -901,12 +918,12 @@ BYTEA bytea variable-length byte array (null-safe)
901918
If you are using a client interface like ODBC you may need to set
902919
auto-commit off.
903920

904-
4.21) How do I create a column that will default to the current time?
921+
4.22) How do I create a column that will default to the current time?
905922

906923
Use now():
907924
CREATE TABLE test (x int, modtime timestamp DEFAULT now() );
908925

909-
4.22) Why are my subqueries using IN so slow?
926+
4.23) Why are my subqueries using IN so slow?
910927

911928
Currently, we join subqueries to outer queries by sequentially
912929
scanning the result of the subquery for each row of the outer query. A
@@ -922,7 +939,7 @@ SELECT *
922939

923940
We hope to fix this limitation in a future release.
924941

925-
4.23) How do I perform an outer join?
942+
4.24) How do I perform an outer join?
926943

927944
PostgreSQL 7.1 and later supports outer joins using the SQL standard
928945
syntax. Here are two examples:

‎doc/src/FAQ/FAQ.html‎

Lines changed: 32 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -127,15 +127,17 @@ <H2>Operational Questions</H2>
127127
<SMALL>TID</SMALL>?<BR>
128128
<Ahref="#4.18">4.18</A>) What is the meaning of some of the terms
129129
used in PostgreSQL?<BR>
130-
<Ahref="#4.19">4.19</A>) How do I tell what PostgreSQL version I
130+
<Ahref="#4.19">4.19</A>) Why do I get the error<I>"ERROR:
131+
Memory exhausted in AllocSetAlloc()?"</I><BR>
132+
<Ahref="#4.20">4.20</A>) How do I tell what PostgreSQL version I
131133
am running?<BR>
132-
<Ahref="#4.20">4.20</A>) My large-object operations get
134+
<Ahref="#4.21">4.21</A>) My large-object operations get
133135
<I>invalid large obj descriptor.</I> Why?<BR>
134-
<Ahref="#4.21">4.21</A>) How do I create a column that will
136+
<Ahref="#4.22">4.22</A>) How do I create a column that will
135137
default to the current time?<BR>
136-
<Ahref="#4.22">4.22</A>) Why are my subqueries using
138+
<Ahref="#4.23">4.23</A>) Why are my subqueries using
137139
<CODE><SMALL>IN</SMALL></CODE> so slow?<BR>
138-
<Ahref="#4.23">4.23</A>) How do I perform an outer join?<BR>
140+
<Ahref="#4.24">4.24</A>) How do I perform an outer join?<BR>
139141

140142

141143
<CENTER>
@@ -147,7 +149,7 @@ <H2>Extending PostgreSQL</H2>
147149
and functions to PostgreSQL?<BR>
148150
<Ahref="#5.3">5.3</A>) How do I write a C function to return a
149151
tuple?<BR>
150-
<Ahref="#5.4">5.4</A>) I have changed a source file. Why does the
152+
<Ahref="#5.4">5.3</A>) I have changed a source file. Why does the
151153
recompile not see the change?<BR>
152154

153155
<HR>
@@ -1132,13 +1134,32 @@ <H4><A name="4.18">4.18</A>) What is the meaning of some of the
11321134
<P>A list of general database terms can be found at:<Ahref=
11331135
"http://www.comptechnews.com/~reaster/dbdesign.html">http://www.comptechnews.com/~reaster/dbdesign.html</A></P>
11341136

1135-
<H4><Aname="4.19">4.19</A>) How do I tell what PostgreSQL version
1137+
<H4><Aname="4.19">4.19</A>) Why do I get the error<I>"ERROR:
1138+
Memory exhausted in AllocSetAlloc()?"</I><BR>
1139+
</H4>
1140+
1141+
<P>It is possible you have run out of virtual memory on your
1142+
system, or your kernel has a low limit for certain resources. Try
1143+
this before starting the<I>postmaster:</I></P>
1144+
<PRE>
1145+
ulimit -d 262144
1146+
limit datasize 256m
1147+
</PRE>
1148+
Depending on your shell, only one of these may succeed, but it will
1149+
set your process data segment limit much higher and perhaps allow
1150+
the query to complete. This command applies to the current process,
1151+
and all subprocesses created after the command is run. If you are
1152+
having a problem with the<SMALL>SQL</SMALL> client because the
1153+
backend is returning too much data, try it before starting the
1154+
client.
1155+
1156+
<H4><Aname="4.20">4.20</A>) How do I tell what PostgreSQL version
11361157
I am running?<BR>
11371158
</H4>
11381159

11391160
<P>From<I>psql,</I> type<CODE>select version();</CODE></P>
11401161

1141-
<H4><Aname="4.20">4.20</A>) My large-object operations get
1162+
<H4><Aname="4.21">4.21</A>) My large-object operations get
11421163
<I>invalid large obj descriptor.</I> Why?<BR>
11431164
</H4>
11441165

@@ -1155,7 +1176,7 @@ <H4><A name="4.20">4.20</A>) My large-object operations get
11551176
<P>If you are using a client interface like<SMALL>ODBC</SMALL> you
11561177
may need to set<CODE>auto-commit off.</CODE></P>
11571178

1158-
<H4><Aname="4.21">4.21</A>) How do I create a column that will
1179+
<H4><Aname="4.22">4.22</A>) How do I create a column that will
11591180
default to the current time?<BR>
11601181
</H4>
11611182

@@ -1165,7 +1186,7 @@ <H4><A name="4.21">4.21</A>) How do I create a column that will
11651186
</CODE>
11661187
</PRE>
11671188

1168-
<H4><Aname="4.22">4.22</A>) Why are my subqueries using
1189+
<H4><Aname="4.23">4.23</A>) Why are my subqueries using
11691190
<CODE><SMALL>IN</SMALL></CODE> so slow?<BR>
11701191
</H4>
11711192

@@ -1188,7 +1209,7 @@ <H4><A name="4.22">4.22</A>) Why are my subqueries using
11881209
</PRE>
11891210
We hope to fix this limitation in a future release.
11901211

1191-
<H4><Aname="4.23">4.23</A>) How do I perform an outer join?<BR>
1212+
<H4><Aname="4.24">4.24</A>) How do I perform an outer join?<BR>
11921213
</H4>
11931214

11941215
<P>PostgreSQL 7.1 and later supports outer joins using the SQL

0 commit comments

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