Frequently Asked Questions (FAQ) for POSTGRESQL
Last updated: Wed Jul 26 13:31:44 EDT 2000
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
The most recent version of this document can be viewed at
http://www.PostgreSQL.org/docs/faq-english.html.
Platform-specific questions are answered at http://www.PostgreSQL.org/docs/.
1.1) What is POSTGRESQL?
1.2) What's the copyright on POSTGRESQL?
1.3) What Unix platforms does POSTGRESQL run on?
1.4) What non-Unix ports are available?
1.5) Where can I get POSTGRESQL?
1.6) Where can I get support?
1.7) What is the latest release?
1.8) What documentation is available?
1.9) How do I find out about known bugs or missing features?
1.10) How can I learn SQL?
1.11) Is POSTGRESQL Y2K compliant?
1.12) How do I join the development team?
1.13) How do I submit a bug report?
1.14) How does POSTGRESQL compare to other DBMS's?
2.1) Are there ODBC drivers for POSTGRESQL?
2.2) What tools are available for hooking POSTGRESQL to Web pages?
2.3) Does POSTGRESQL have a graphical user interface? A report generator? An embedded query language interface?
2.4) What languages are available to communicate with POSTGRESQL?
3.1) Why does initdb fail?
3.2) How do I install POSTGRESQL somewhere other than /usr/local/pgsql?
3.3) When I start the postmaster, I get a Bad System Call or core dumped message. Why?
3.4) When I try to start the postmaster, I get IpcMemoryCreate errors. Why?
3.5) When I try to start the postmaster, I get IpcSemaphoreCreate errors. Why?
3.6) How do I prevent other hosts from accessing my POSTGRESQL database?
3.7) Why can't I connect to my database from another machine?
3.8) Why can't I access the database as the root user?
3.9) All my servers crash under concurrent table access. Why?
3.10) How do I tune the database engine for better performance?
3.11) What debugging features are available?
3.12) I get ``Sorry, too many clients'' when trying to connect. Why?
3.13) What are the pg_sorttempNNN.NN files in my database directory?
4.1) Why is the system confused about commas, decimal points, and date formats?
4.2) What is the exact difference between binary cursors and normal cursors?
4.3) How do I SELECT only the first few rows of a query?
4.4) How do I get a list of tables or other things I can see in psql?
4.5) How do you remove a column from a table?
4.6) What is the maximum size for a row, table, database?
4.7) How much database disk space is required to store data from a typical text file?
4.8) How do I find out what indices or operations are defined in the database?
4.9) My queries are slow or don't make use of the indexes. Why?
4.10) How do I see how the query optimizer is evaluating my query?
4.11) What is an R-tree index?
4.12) What is Genetic Query Optimization?
4.13) How do I do regular expression searches and case-insensitive regular expression searches?
4.14) In a query, how do I detect if a field is NULL?
4.15) What is the difference between the various character types?
4.16.1) How do I create a serial/auto-incrementing field?
4.16.2) How do I get the value of a SERIAL insert?
4.16.3) Don't currval() and nextval() lead to a race condition with 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) Why do I get the error "FATAL: palloc failure: memory exhausted?"
4.20) How do I tell what POSTGRESQL version I am running?
4.21) My large-object operations get invalid large obj descriptor. Why?
4.22) 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 do an outer join?
5.1) I wrote a user-defined function. When I run it in psql, why does it dump core?
5.2) What does the message ``NOTICE:PortalHeapMemoryFree: 0x402251d0 not in alloc set!'' mean?
5.3) How can I contribute some nifty new types and functions to POSTGRESQL?
5.4) How do I write a C function to return a tuple?
5.5) I have changed a source file. Why does the recompile not see the change?