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pg_config_manual.h
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/*------------------------------------------------------------------------ * 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) 1996-2012, 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 INT64CONST(0x7FFFFFFFFFFFFFFF) #define SEQ_MINVALUE (-SEQ_MAXVALUE) /* * Number of spare LWLocks to allocate for user-defined add-on code. */ #define NUM_USER_DEFINED_LWLOCKS 4 /* * 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 /* * 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 /* * 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" /* * 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 (0x7FFFFFFF) /* * Set the format style used by gcc to check printf type functions. We really * want the "gnu_printf" style set, which includes what glibc uses, such * as %m for error strings and %lld for 64 bit long longs. But not all gcc * compilers are known to support it, so we just use "printf" which all * gcc versions alive are known to support, except on Windows where * using "gnu_printf" style makes a dramatic difference. Maybe someday * we'll have a configure test for this, if we ever discover use of more * variants to be necessary. */ #ifdef WIN32 #define PG_PRINTF_ATTRIBUTE gnu_printf #else #define PG_PRINTF_ATTRIBUTE printf #endif /* * 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 /* *------------------------------------------------------------------------ * The following symbols are for enabling debugging code, not for * controlling user-visible features or resource limits. *------------------------------------------------------------------------ */ /* * 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. */ #ifdef USE_ASSERT_CHECKING #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 */ /* * 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 */ /* #define RTDEBUG */