File: pg_config_manual.h

package info (click to toggle)
postgresql-9.6 9.6.15-0+deb9u1
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 129,420 kB
  • sloc: ansic: 742,939; sql: 67,276; xml: 30,901; yacc: 30,445; perl: 16,293; lex: 7,764; sh: 5,290; makefile: 4,780; python: 112; asm: 65; sed: 15
file content (327 lines) | stat: -rw-r--r-- 11,652 bytes parent folder | download | duplicates (4)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
/*------------------------------------------------------------------------
 * PostgreSQL manual configuration settings
 *
 * This file contains various configuration symbols and limits.  In
 * all cases, changing them is only useful in very rare situations or
 * for developers.  If you edit any of these, be sure to do a *full*
 * rebuild (and an initdb if noted).
 *
 * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/pg_config_manual.h
 *------------------------------------------------------------------------
 */

/*
 * Maximum length for identifiers (e.g. table names, column names,
 * function names).  Names actually are limited to one less byte than this,
 * because the length must include a trailing zero byte.
 *
 * Changing this requires an initdb.
 */
#define NAMEDATALEN 64

/*
 * Maximum number of arguments to a function.
 *
 * The minimum value is 8 (GIN indexes use 8-argument support functions).
 * The maximum possible value is around 600 (limited by index tuple size in
 * pg_proc's index; BLCKSZ larger than 8K would allow more).  Values larger
 * than needed will waste memory and processing time, but do not directly
 * cost disk space.
 *
 * Changing this does not require an initdb, but it does require a full
 * backend recompile (including any user-defined C functions).
 */
#define FUNC_MAX_ARGS		100

/*
 * Maximum number of columns in an index.  There is little point in making
 * this anything but a multiple of 32, because the main cost is associated
 * with index tuple header size (see access/itup.h).
 *
 * Changing this requires an initdb.
 */
#define INDEX_MAX_KEYS		32

/*
 * Set the upper and lower bounds of sequence values.
 */
#define SEQ_MAXVALUE	PG_INT64_MAX
#define SEQ_MINVALUE	(-SEQ_MAXVALUE)

/*
 * When we don't have native spinlocks, we use semaphores to simulate them.
 * Decreasing this value reduces consumption of OS resources; increasing it
 * may improve performance, but supplying a real spinlock implementation is
 * probably far better.
 */
#define NUM_SPINLOCK_SEMAPHORES		128

/*
 * When we have neither spinlocks nor atomic operations support we're
 * implementing atomic operations on top of spinlock on top of semaphores. To
 * be safe against atomic operations while holding a spinlock separate
 * semaphores have to be used.
 */
#define NUM_ATOMICS_SEMAPHORES		64

/*
 * Define this if you want to allow the lo_import and lo_export SQL
 * functions to be executed by ordinary users.  By default these
 * functions are only available to the Postgres superuser.  CAUTION:
 * These functions are SECURITY HOLES since they can read and write
 * any file that the PostgreSQL server has permission to access.  If
 * you turn this on, don't say we didn't warn you.
 */
/* #define ALLOW_DANGEROUS_LO_FUNCTIONS */

/*
 * MAXPGPATH: standard size of a pathname buffer in PostgreSQL (hence,
 * maximum usable pathname length is one less).
 *
 * We'd use a standard system header symbol for this, if there weren't
 * so many to choose from: MAXPATHLEN, MAX_PATH, PATH_MAX are all
 * defined by different "standards", and often have different values
 * on the same platform!  So we just punt and use a reasonably
 * generous setting here.
 */
#define MAXPGPATH		1024

/*
 * PG_SOMAXCONN: maximum accept-queue length limit passed to
 * listen(2).  You'd think we should use SOMAXCONN from
 * <sys/socket.h>, but on many systems that symbol is much smaller
 * than the kernel's actual limit.  In any case, this symbol need be
 * twiddled only if you have a kernel that refuses large limit values,
 * rather than silently reducing the value to what it can handle
 * (which is what most if not all Unixen do).
 */
#define PG_SOMAXCONN	10000

/*
 * You can try changing this if you have a machine with bytes of
 * another size, but no guarantee...
 */
#define BITS_PER_BYTE		8

/*
 * Preferred alignment for disk I/O buffers.  On some CPUs, copies between
 * user space and kernel space are significantly faster if the user buffer
 * is aligned on a larger-than-MAXALIGN boundary.  Ideally this should be
 * a platform-dependent value, but for now we just hard-wire it.
 */
#define ALIGNOF_BUFFER	32

/*
 * Disable UNIX sockets for certain operating systems.
 */
#if defined(WIN32)
#undef HAVE_UNIX_SOCKETS
#endif

/*
 * Define this if your operating system supports link()
 */
#if !defined(WIN32) && !defined(__CYGWIN__)
#define HAVE_WORKING_LINK 1
#endif

/*
 * USE_POSIX_FADVISE controls whether Postgres will attempt to use the
 * posix_fadvise() kernel call.  Usually the automatic configure tests are
 * sufficient, but some older Linux distributions had broken versions of
 * posix_fadvise().  If necessary you can remove the #define here.
 */
#if HAVE_DECL_POSIX_FADVISE && defined(HAVE_POSIX_FADVISE)
#define USE_POSIX_FADVISE
#endif

/*
 * USE_PREFETCH code should be compiled only if we have a way to implement
 * prefetching.  (This is decoupled from USE_POSIX_FADVISE because there
 * might in future be support for alternative low-level prefetch APIs.)
 */
#ifdef USE_POSIX_FADVISE
#define USE_PREFETCH
#endif

/*
 * Default and maximum values for backend_flush_after, bgwriter_flush_after
 * and checkpoint_flush_after; measured in blocks.  Currently, these are
 * enabled by default if sync_file_range() exists, ie, only on Linux.  Perhaps
 * we could also enable by default if we have mmap and msync(MS_ASYNC)?
 */
#ifdef HAVE_SYNC_FILE_RANGE
#define DEFAULT_BACKEND_FLUSH_AFTER 0	/* never enabled by default */
#define DEFAULT_BGWRITER_FLUSH_AFTER 64
#define DEFAULT_CHECKPOINT_FLUSH_AFTER 32
#else
#define DEFAULT_BACKEND_FLUSH_AFTER 0
#define DEFAULT_BGWRITER_FLUSH_AFTER 0
#define DEFAULT_CHECKPOINT_FLUSH_AFTER 0
#endif
/* upper limit for all three variables */
#define WRITEBACK_MAX_PENDING_FLUSHES 256

/*
 * USE_SSL code should be compiled only when compiling with an SSL
 * implementation.  (Currently, only OpenSSL is supported, but we might add
 * more implementations in the future.)
 */
#ifdef USE_OPENSSL
#define USE_SSL
#endif

/*
 * This is the default directory in which AF_UNIX socket files are
 * placed.  Caution: changing this risks breaking your existing client
 * applications, which are likely to continue to look in the old
 * directory.  But if you just hate the idea of sockets in /tmp,
 * here's where to twiddle it.  You can also override this at runtime
 * with the postmaster's -k switch.
 */
#define DEFAULT_PGSOCKET_DIR  "/var/run/postgresql"

/*
 * This is the default event source for Windows event log.
 */
#define DEFAULT_EVENT_SOURCE  "PostgreSQL"

/*
 * The random() function is expected to yield values between 0 and
 * MAX_RANDOM_VALUE.  Currently, all known implementations yield
 * 0..2^31-1, so we just hardwire this constant.  We could do a
 * configure test if it proves to be necessary.  CAUTION: Think not to
 * replace this with RAND_MAX.  RAND_MAX defines the maximum value of
 * the older rand() function, which is often different from --- and
 * considerably inferior to --- random().
 */
#define MAX_RANDOM_VALUE  PG_INT32_MAX

/*
 * On PPC machines, decide whether to use the mutex hint bit in LWARX
 * instructions.  Setting the hint bit will slightly improve spinlock
 * performance on POWER6 and later machines, but does nothing before that,
 * and will result in illegal-instruction failures on some pre-POWER4
 * machines.  By default we use the hint bit when building for 64-bit PPC,
 * which should be safe in nearly all cases.  You might want to override
 * this if you are building 32-bit code for a known-recent PPC machine.
 */
#ifdef HAVE_PPC_LWARX_MUTEX_HINT	/* must have assembler support in any case */
#if defined(__ppc64__) || defined(__powerpc64__)
#define USE_PPC_LWARX_MUTEX_HINT
#endif
#endif

/*
 * On PPC machines, decide whether to use LWSYNC instructions in place of
 * ISYNC and SYNC.  This provides slightly better performance, but will
 * result in illegal-instruction failures on some pre-POWER4 machines.
 * By default we use LWSYNC when building for 64-bit PPC, which should be
 * safe in nearly all cases.
 */
#if defined(__ppc64__) || defined(__powerpc64__)
#define USE_PPC_LWSYNC
#endif

/*
 * Assumed cache line size. This doesn't affect correctness, but can be used
 * for low-level optimizations. Currently, this is used to pad some data
 * structures in xlog.c, to ensure that highly-contended fields are on
 * different cache lines. Too small a value can hurt performance due to false
 * sharing, while the only downside of too large a value is a few bytes of
 * wasted memory. The default is 128, which should be large enough for all
 * supported platforms.
 */
#define PG_CACHE_LINE_SIZE		128

/*
 *------------------------------------------------------------------------
 * The following symbols are for enabling debugging code, not for
 * controlling user-visible features or resource limits.
 *------------------------------------------------------------------------
 */

/*
 * Include Valgrind "client requests", mostly in the memory allocator, so
 * Valgrind understands PostgreSQL memory contexts.  This permits detecting
 * memory errors that Valgrind would not detect on a vanilla build.  See also
 * src/tools/valgrind.supp.  "make installcheck" runs 20-30x longer under
 * Valgrind.  Note that USE_VALGRIND slowed older versions of Valgrind by an
 * additional order of magnitude; Valgrind 3.8.1 does not have this problem.
 * The client requests fall in hot code paths, so USE_VALGRIND also slows
 * native execution by a few percentage points.
 *
 * You should normally use MEMORY_CONTEXT_CHECKING with USE_VALGRIND;
 * instrumentation of repalloc() is inferior without it.
 */
/* #define USE_VALGRIND */

/*
 * Define this to cause pfree()'d memory to be cleared immediately, to
 * facilitate catching bugs that refer to already-freed values.
 * Right now, this gets defined automatically if --enable-cassert.
 */
#ifdef USE_ASSERT_CHECKING
#define CLOBBER_FREED_MEMORY
#endif

/*
 * Define this to check memory allocation errors (scribbling on more
 * bytes than were allocated).  Right now, this gets defined
 * automatically if --enable-cassert or USE_VALGRIND.
 */
#if defined(USE_ASSERT_CHECKING) || defined(USE_VALGRIND)
#define MEMORY_CONTEXT_CHECKING
#endif

/*
 * Define this to cause palloc()'d memory to be filled with random data, to
 * facilitate catching code that depends on the contents of uninitialized
 * memory.  Caution: this is horrendously expensive.
 */
/* #define RANDOMIZE_ALLOCATED_MEMORY */

/*
 * Define this to force all parse and plan trees to be passed through
 * copyObject(), to facilitate catching errors and omissions in
 * copyObject().
 */
/* #define COPY_PARSE_PLAN_TREES */

/*
 * Define this to force all raw parse trees for DML statements to be scanned
 * by raw_expression_tree_walker(), to facilitate catching errors and
 * omissions in that function.
 */
/* #define RAW_EXPRESSION_COVERAGE_TEST */

/*
 * Enable debugging print statements for lock-related operations.
 */
/* #define LOCK_DEBUG */

/*
 * Enable debugging print statements for WAL-related operations; see
 * also the wal_debug GUC var.
 */
/* #define WAL_DEBUG */

/*
 * Enable tracing of resource consumption during sort operations;
 * see also the trace_sort GUC var.  For 8.1 this is enabled by default.
 */
#define TRACE_SORT 1

/*
 * Enable tracing of syncscan operations (see also the trace_syncscan GUC var).
 */
/* #define TRACE_SYNCSCAN */

/*
 * Other debug #defines (documentation, anyone?)
 */
/* #define HEAPDEBUGALL */
/* #define ACLDEBUG */