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Diffstat (limited to 'doc/FAQ')
| -rw-r--r-- | doc/FAQ | 39 |
1 files changed, 28 insertions, 11 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: |