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| -rw-r--r-- | doc/FAQ | 39 | ||||
| -rw-r--r-- | doc/src/FAQ/FAQ.html | 43 |
2 files changed, 60 insertions, 22 deletions
@@ -83,12 +83,14 @@ other users? 4.17) What is an OID? What is a TID? 4.18) What is the meaning of some of the terms used in PostgreSQL? - 4.19) How do I tell what PostgreSQL version I am running? - 4.20) My large-object operations get invalid large obj descriptor. + 4.19) Why do I get the error "ERROR: Memory exhausted in + AllocSetAlloc()?" + 4.20) How do I tell what PostgreSQL version I am running? + 4.21) My large-object operations get invalid large obj descriptor. Why? - 4.21) How do I create a column that will default to the current time? - 4.22) Why are my subqueries using IN so slow? - 4.23) How do I perform an outer join? + 4.22) How do I create a column that will default to the current time? + 4.23) Why are my subqueries using IN so slow? + 4.24) How do I perform an outer join? Extending PostgreSQL @@ -97,7 +99,7 @@ 5.2) How can I contribute some nifty new types and functions to PostgreSQL? 5.3) How do I write a C function to return a tuple? - 5.4) I have changed a source file. Why does the recompile not see the + 5.3) I have changed a source file. Why does the recompile not see the change? _________________________________________________________________ @@ -883,11 +885,26 @@ BYTEA bytea variable-length byte array (null-safe) A list of general database terms can be found at: http://www.comptechnews.com/~reaster/dbdesign.html - 4.19) How do I tell what PostgreSQL version I am running? + 4.19) Why do I get the error "ERROR: Memory exhausted in AllocSetAlloc()?" + + It is possible you have run out of virtual memory on your system, or + your kernel has a low limit for certain resources. Try this before + starting the postmaster: + ulimit -d 262144 + limit datasize 256m + + Depending on your shell, only one of these may succeed, but it will + set your process data segment limit much higher and perhaps allow the + query to complete. This command applies to the current process, and + all subprocesses created after the command is run. If you are having a + problem with the SQL client because the backend is returning too much + data, try it before starting the client. + + 4.20) How do I tell what PostgreSQL version I am running? From psql, type select version(); - 4.20) My large-object operations get invalid large obj descriptor. Why? + 4.21) My large-object operations get invalid large obj descriptor. Why? You need to put BEGIN WORK and COMMIT around any use of a large object handle, that is, surrounding lo_open ... lo_close. @@ -901,12 +918,12 @@ BYTEA bytea variable-length byte array (null-safe) If you are using a client interface like ODBC you may need to set auto-commit off. - 4.21) How do I create a column that will default to the current time? + 4.22) How do I create a column that will default to the current time? Use now(): CREATE TABLE test (x int, modtime timestamp DEFAULT now() ); - 4.22) Why are my subqueries using IN so slow? + 4.23) Why are my subqueries using IN so slow? Currently, we join subqueries to outer queries by sequentially scanning the result of the subquery for each row of the outer query. A @@ -922,7 +939,7 @@ SELECT * We hope to fix this limitation in a future release. - 4.23) How do I perform an outer join? + 4.24) How do I perform an outer join? PostgreSQL 7.1 and later supports outer joins using the SQL standard syntax. Here are two examples: diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html index 59ad51047f8..61d955211ed 100644 --- a/doc/src/FAQ/FAQ.html +++ b/doc/src/FAQ/FAQ.html @@ -127,15 +127,17 @@ <SMALL>TID</SMALL>?<BR> <A href="#4.18">4.18</A>) What is the meaning of some of the terms used in PostgreSQL?<BR> - <A href="#4.19">4.19</A>) How do I tell what PostgreSQL version I + <A href="#4.19">4.19</A>) Why do I get the error <I>"ERROR: + Memory exhausted in AllocSetAlloc()?"</I><BR> + <A href="#4.20">4.20</A>) How do I tell what PostgreSQL version I am running? <BR> - <A href="#4.20">4.20</A>) My large-object operations get + <A href="#4.21">4.21</A>) My large-object operations get <I>invalid large obj descriptor.</I> Why?<BR> - <A href="#4.21">4.21</A>) How do I create a column that will + <A href="#4.22">4.22</A>) How do I create a column that will default to the current time?<BR> - <A href="#4.22">4.22</A>) Why are my subqueries using + <A href="#4.23">4.23</A>) Why are my subqueries using <CODE><SMALL>IN</SMALL></CODE> so slow?<BR> - <A href="#4.23">4.23</A>) How do I perform an outer join?<BR> + <A href="#4.24">4.24</A>) How do I perform an outer join?<BR> <CENTER> @@ -147,7 +149,7 @@ and functions to PostgreSQL?<BR> <A href="#5.3">5.3</A>) How do I write a C function to return a tuple?<BR> - <A href="#5.4">5.4</A>) I have changed a source file. Why does the + <A href="#5.4">5.3</A>) I have changed a source file. Why does the recompile not see the change?<BR> <HR> @@ -1132,13 +1134,32 @@ BYTEA bytea variable-length byte array (null-safe) <P>A list of general database terms can be found at: <A href= "http://www.comptechnews.com/~reaster/dbdesign.html">http://www.comptechnews.com/~reaster/dbdesign.html</A></P> - <H4><A name="4.19">4.19</A>) How do I tell what PostgreSQL version + <H4><A name="4.19">4.19</A>) Why do I get the error <I>"ERROR: + Memory exhausted in AllocSetAlloc()?"</I><BR> + </H4> + + <P>It is possible you have run out of virtual memory on your + system, or your kernel has a low limit for certain resources. Try + this before starting the <I>postmaster:</I></P> +<PRE> + ulimit -d 262144 + limit datasize 256m +</PRE> + Depending on your shell, only one of these may succeed, but it will + set your process data segment limit much higher and perhaps allow + the query to complete. This command applies to the current process, + and all subprocesses created after the command is run. If you are + having a problem with the <SMALL>SQL</SMALL> client because the + backend is returning too much data, try it before starting the + client. + + <H4><A name="4.20">4.20</A>) How do I tell what PostgreSQL version I am running?<BR> </H4> <P>From <I>psql,</I> type <CODE>select version();</CODE></P> - <H4><A name="4.20">4.20</A>) My large-object operations get + <H4><A name="4.21">4.21</A>) My large-object operations get <I>invalid large obj descriptor.</I> Why?<BR> </H4> @@ -1155,7 +1176,7 @@ BYTEA bytea variable-length byte array (null-safe) <P>If you are using a client interface like <SMALL>ODBC</SMALL> you may need to set <CODE>auto-commit off.</CODE></P> - <H4><A name="4.21">4.21</A>) How do I create a column that will + <H4><A name="4.22">4.22</A>) How do I create a column that will default to the current time?<BR> </H4> @@ -1165,7 +1186,7 @@ BYTEA bytea variable-length byte array (null-safe) </CODE> </PRE> - <H4><A name="4.22">4.22</A>) Why are my subqueries using + <H4><A name="4.23">4.23</A>) Why are my subqueries using <CODE><SMALL>IN</SMALL></CODE> so slow?<BR> </H4> @@ -1188,7 +1209,7 @@ BYTEA bytea variable-length byte array (null-safe) </PRE> We hope to fix this limitation in a future release. - <H4><A name="4.23">4.23</A>) How do I perform an outer join?<BR> + <H4><A name="4.24">4.24</A>) How do I perform an outer join?<BR> </H4> <P>PostgreSQL 7.1 and later supports outer joins using the SQL |