1 /*------------------------------------------------------------------------
2 * PostgreSQL manual configuration settings
4 * This file contains various configuration symbols and limits. In
5 * all cases, changing them is only useful in very rare situations or
6 * for developers. If you edit any of these, be sure to do a *full*
7 * rebuild (and an initdb if noted).
9 * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
10 * Portions Copyright (c) 1994, Regents of the University of California
12 * src/include/pg_config_manual.h
13 *------------------------------------------------------------------------
17 * Maximum length for identifiers (e.g. table names, column names,
18 * function names). Names actually are limited to one less byte than this,
19 * because the length must include a trailing zero byte.
21 * Changing this requires an initdb.
23 #define NAMEDATALEN 64
26 * Maximum number of arguments to a function.
28 * The minimum value is 8 (GIN indexes use 8-argument support functions).
29 * The maximum possible value is around 600 (limited by index tuple size in
30 * pg_proc's index; BLCKSZ larger than 8K would allow more). Values larger
31 * than needed will waste memory and processing time, but do not directly
34 * Changing this does not require an initdb, but it does require a full
35 * backend recompile (including any user-defined C functions).
37 #define FUNC_MAX_ARGS 100
40 * Maximum number of columns in an index. There is little point in making
41 * this anything but a multiple of 32, because the main cost is associated
42 * with index tuple header size (see access/itup.h).
44 * Changing this requires an initdb.
46 #define INDEX_MAX_KEYS 32
49 * Set the upper and lower bounds of sequence values.
51 #define SEQ_MAXVALUE INT64CONST(0x7FFFFFFFFFFFFFFF)
52 #define SEQ_MINVALUE (-SEQ_MAXVALUE)
55 * Number of spare LWLocks to allocate for user-defined add-on code.
57 #define NUM_USER_DEFINED_LWLOCKS 4
60 * When we don't have native spinlocks, we use semaphores to simulate them.
61 * Decreasing this value reduces consumption of OS resources; increasing it
62 * may improve performance, but supplying a real spinlock implementation is
63 * probably far better.
65 #define NUM_SPINLOCK_SEMAPHORES 1024
68 * Define this if you want to allow the lo_import and lo_export SQL
69 * functions to be executed by ordinary users. By default these
70 * functions are only available to the Postgres superuser. CAUTION:
71 * These functions are SECURITY HOLES since they can read and write
72 * any file that the PostgreSQL server has permission to access. If
73 * you turn this on, don't say we didn't warn you.
75 /* #define ALLOW_DANGEROUS_LO_FUNCTIONS */
78 * MAXPGPATH: standard size of a pathname buffer in PostgreSQL (hence,
79 * maximum usable pathname length is one less).
81 * We'd use a standard system header symbol for this, if there weren't
82 * so many to choose from: MAXPATHLEN, MAX_PATH, PATH_MAX are all
83 * defined by different "standards", and often have different values
84 * on the same platform! So we just punt and use a reasonably
85 * generous setting here.
87 #define MAXPGPATH 1024
90 * PG_SOMAXCONN: maximum accept-queue length limit passed to
91 * listen(2). You'd think we should use SOMAXCONN from
92 * <sys/socket.h>, but on many systems that symbol is much smaller
93 * than the kernel's actual limit. In any case, this symbol need be
94 * twiddled only if you have a kernel that refuses large limit values,
95 * rather than silently reducing the value to what it can handle
96 * (which is what most if not all Unixen do).
98 #define PG_SOMAXCONN 10000
101 * You can try changing this if you have a machine with bytes of
102 * another size, but no guarantee...
104 #define BITS_PER_BYTE 8
107 * Preferred alignment for disk I/O buffers. On some CPUs, copies between
108 * user space and kernel space are significantly faster if the user buffer
109 * is aligned on a larger-than-MAXALIGN boundary. Ideally this should be
110 * a platform-dependent value, but for now we just hard-wire it.
112 #define ALIGNOF_BUFFER 32
115 * Disable UNIX sockets for certain operating systems.
118 #undef HAVE_UNIX_SOCKETS
122 * Define this if your operating system supports link()
124 #if !defined(WIN32) && !defined(__CYGWIN__)
125 #define HAVE_WORKING_LINK 1
129 * USE_POSIX_FADVISE controls whether Postgres will attempt to use the
130 * posix_fadvise() kernel call. Usually the automatic configure tests are
131 * sufficient, but some older Linux distributions had broken versions of
132 * posix_fadvise(). If necessary you can remove the #define here.
134 #if HAVE_DECL_POSIX_FADVISE && defined(HAVE_POSIX_FADVISE)
135 #define USE_POSIX_FADVISE
139 * USE_PREFETCH code should be compiled only if we have a way to implement
140 * prefetching. (This is decoupled from USE_POSIX_FADVISE because there
141 * might in future be support for alternative low-level prefetch APIs.)
143 #ifdef USE_POSIX_FADVISE
148 * This is the default directory in which AF_UNIX socket files are
149 * placed. Caution: changing this risks breaking your existing client
150 * applications, which are likely to continue to look in the old
151 * directory. But if you just hate the idea of sockets in /tmp,
152 * here's where to twiddle it. You can also override this at runtime
153 * with the postmaster's -k switch.
155 #define DEFAULT_PGSOCKET_DIR "/tmp"
158 * This is the default event source for Windows event log.
160 #define DEFAULT_EVENT_SOURCE "PostgreSQL"
163 * The random() function is expected to yield values between 0 and
164 * MAX_RANDOM_VALUE. Currently, all known implementations yield
165 * 0..2^31-1, so we just hardwire this constant. We could do a
166 * configure test if it proves to be necessary. CAUTION: Think not to
167 * replace this with RAND_MAX. RAND_MAX defines the maximum value of
168 * the older rand() function, which is often different from --- and
169 * considerably inferior to --- random().
171 #define MAX_RANDOM_VALUE (0x7FFFFFFF)
174 * Set the format style used by gcc to check printf type functions. We really
175 * want the "gnu_printf" style set, which includes what glibc uses, such
176 * as %m for error strings and %lld for 64 bit long longs. But not all gcc
177 * compilers are known to support it, so we just use "printf" which all
178 * gcc versions alive are known to support, except on Windows where
179 * using "gnu_printf" style makes a dramatic difference. Maybe someday
180 * we'll have a configure test for this, if we ever discover use of more
181 * variants to be necessary.
184 #define PG_PRINTF_ATTRIBUTE gnu_printf
186 #define PG_PRINTF_ATTRIBUTE printf
190 * On PPC machines, decide whether to use the mutex hint bit in LWARX
191 * instructions. Setting the hint bit will slightly improve spinlock
192 * performance on POWER6 and later machines, but does nothing before that,
193 * and will result in illegal-instruction failures on some pre-POWER4
194 * machines. By default we use the hint bit when building for 64-bit PPC,
195 * which should be safe in nearly all cases. You might want to override
196 * this if you are building 32-bit code for a known-recent PPC machine.
198 #ifdef HAVE_PPC_LWARX_MUTEX_HINT /* must have assembler support in any case */
199 #if defined(__ppc64__) || defined(__powerpc64__)
200 #define USE_PPC_LWARX_MUTEX_HINT
205 * On PPC machines, decide whether to use LWSYNC instructions in place of
206 * ISYNC and SYNC. This provides slightly better performance, but will
207 * result in illegal-instruction failures on some pre-POWER4 machines.
208 * By default we use LWSYNC when building for 64-bit PPC, which should be
209 * safe in nearly all cases.
211 #if defined(__ppc64__) || defined(__powerpc64__)
212 #define USE_PPC_LWSYNC
216 * Assumed cache line size. This doesn't affect correctness, but can be
217 * used for low-level optimizations. Currently, this is only used to pad
218 * some data structures in xlog.c, to ensure that highly-contended fields
219 * are on different cache lines. Too small a value can hurt performance due
220 * to false sharing, while the only downside of too large a value is a few
221 * bytes of wasted memory. The default is 128, which should be large enough
222 * for all supported platforms.
224 #define CACHE_LINE_SIZE 128
227 *------------------------------------------------------------------------
228 * The following symbols are for enabling debugging code, not for
229 * controlling user-visible features or resource limits.
230 *------------------------------------------------------------------------
234 * Include Valgrind "client requests", mostly in the memory allocator, so
235 * Valgrind understands PostgreSQL memory contexts. This permits detecting
236 * memory errors that Valgrind would not detect on a vanilla build. See also
237 * src/tools/valgrind.supp. "make installcheck" runs 20-30x longer under
238 * Valgrind. Note that USE_VALGRIND slowed older versions of Valgrind by an
239 * additional order of magnitude; Valgrind 3.8.1 does not have this problem.
240 * The client requests fall in hot code paths, so USE_VALGRIND also slows
241 * native execution by a few percentage points.
243 * You should normally use MEMORY_CONTEXT_CHECKING with USE_VALGRIND;
244 * instrumentation of repalloc() is inferior without it.
246 /* #define USE_VALGRIND */
249 * Define this to cause pfree()'d memory to be cleared immediately, to
250 * facilitate catching bugs that refer to already-freed values.
251 * Right now, this gets defined automatically if --enable-cassert.
253 #ifdef USE_ASSERT_CHECKING
254 #define CLOBBER_FREED_MEMORY
258 * Define this to check memory allocation errors (scribbling on more
259 * bytes than were allocated). Right now, this gets defined
260 * automatically if --enable-cassert or USE_VALGRIND.
262 #if defined(USE_ASSERT_CHECKING) || defined(USE_VALGRIND)
263 #define MEMORY_CONTEXT_CHECKING
267 * Define this to cause palloc()'d memory to be filled with random data, to
268 * facilitate catching code that depends on the contents of uninitialized
269 * memory. Caution: this is horrendously expensive.
271 /* #define RANDOMIZE_ALLOCATED_MEMORY */
274 * Define this to force all parse and plan trees to be passed through
275 * copyObject(), to facilitate catching errors and omissions in
278 /* #define COPY_PARSE_PLAN_TREES */
281 * Enable debugging print statements for lock-related operations.
283 /* #define LOCK_DEBUG */
286 * Enable debugging print statements for WAL-related operations; see
287 * also the wal_debug GUC var.
289 /* #define WAL_DEBUG */
292 * Enable tracing of resource consumption during sort operations;
293 * see also the trace_sort GUC var. For 8.1 this is enabled by default.
298 * Enable tracing of syncscan operations (see also the trace_syncscan GUC var).
300 /* #define TRACE_SYNCSCAN */
303 * Other debug #defines (documentation, anyone?)
305 /* #define HEAPDEBUGALL */
306 /* #define ACLDEBUG */
307 /* #define RTDEBUG */
310 * Automatic configuration file name for ALTER SYSTEM.
311 * This file will be used to store values of configuration parameters
312 * set by ALTER SYSTEM command.
314 #define PG_AUTOCONF_FILENAME "postgresql.auto.conf"