PostgreSQL

  +
  Details of the structure being dumped may be found in `+src/include/storage/lock.h+`.
  +
  This parameter is only available if the `+LOCK_DEBUG+` macro was defined when PostgreSQL was compiled.
[.term]#`+trace_lwlocks+` (`+boolean+`) ::
  If on, emit information about lightweight lock usage. Lightweight locks are intended primarily to provide mutual exclusion of access to shared-memory data structures.
  +
  This parameter is only available if the `+LOCK_DEBUG+` macro was defined when PostgreSQL was compiled.
[.term]#`+trace_userlocks+` (`+boolean+`) ::
  If on, emit information about user lock usage. Output is the same as for `+trace_locks+`, only for advisory locks.
  +
  This parameter is only available if the `+LOCK_DEBUG+` macro was defined when PostgreSQL was compiled.
[.term]#`+trace_lock_oidmin+` (`+integer+`) ::
  If set, do not trace locks for tables below this OID (used to avoid output on system tables).
  +
  This parameter is only available if the `+LOCK_DEBUG+` macro was defined when PostgreSQL was compiled.
[.term]#`+trace_lock_table+` (`+integer+`) ::
  Unconditionally trace locks on this table (OID).
  +
  This parameter is only available if the `+LOCK_DEBUG+` macro was defined when PostgreSQL was compiled.
[.term]#`+debug_deadlocks+` (`+boolean+`) ::
  If set, dumps information about all current locks when a deadlock timeout occurs.
  +
  This parameter is only available if the `+LOCK_DEBUG+` macro was defined when PostgreSQL was compiled.
[.term]#`+log_btree_build_stats+` (`+boolean+`) ::
  If set, logs system resource usage statistics (memory and CPU) on various B-tree operations.
  +
  This parameter is only available if the `+BTREE_BUILD_STATS+` macro was defined when PostgreSQL was compiled.
[.term]#`+wal_consistency_checking+` (`+string+`) ::
  This parameter is intended to be used to check for bugs in the WAL redo routines. When enabled, full-page images of any buffers modified in conjunction with the WAL record are added to the record. If the record is subsequently replayed, the system will first apply each record and then test whether the buffers modified by the record match the stored images. In certain cases (such as hint bits), minor variations are acceptable, and will be ignored. Any unexpected differences will result in a fatal error, terminating recovery.
  +
  The default value of this setting is the empty string, which disables the feature. It can be set to `+all+` to check all records, or to a comma-separated list of resource managers to check only records originating from those resource managers. Currently, the supported resource managers are `+heap+`, `+heap2+`, `+btree+`, `+hash+`, `+gin+`, `+gist+`, `+sequence+`, `+spgist+`, `+brin+`, and `+generic+`. Only superusers can change this setting.
[.term]#`+wal_debug+` (`+boolean+`) ::
  If on, emit WAL-related debugging output. This parameter is only available if the `+WAL_DEBUG+` macro was defined when PostgreSQL was compiled.
[.term]#`+ignore_checksum_failure+` (`+boolean+`) ::
  Only has effect if link:app-initdb.html#APP-INITDB-DATA-CHECKSUMS[data checksums] are enabled.
  +
  Detection of a checksum failure during a read normally causes PostgreSQL to report an error, aborting the current transaction. Setting `+ignore_checksum_failure+` to on causes the system to ignore the failure (but still report a warning), and continue processing. This behavior may [.emphasis]#_cause crashes, propagate or hide corruption, or other serious problems_#. However, it may allow you to get past the error and retrieve undamaged tuples that might still be present in the table if the block header is still sane. If the header is corrupt an error will be reported even if this option is enabled. The default setting is `+off+`, and it can only be changed by a superuser.
[.term]#`+zero_damaged_pages+` (`+boolean+`) ::
  Detection of a damaged page header normally causes PostgreSQL to report an error, aborting the current transaction. Setting `+zero_damaged_pages+` to on causes the system to instead report a warning, zero out the damaged page in memory, and continue processing. This behavior [.emphasis]#_will destroy data_#, namely all the rows on the damaged page. However, it does allow you to get past the error and retrieve rows from any undamaged pages that might be present in the table. It is useful for recovering data if corruption has occurred due to a hardware or software error. You should generally not set this on until you have given up hope of recovering data from the damaged pages of a table. Zeroed-out pages are not forced to disk so it is recommended to recreate the table or the index before turning this parameter off again. The default setting is `+off+`, and it can only be changed by a superuser.
[.term]#`+jit_debugging_support+` (`+boolean+`) ::
  If LLVM has the required functionality, register generated functions with GDB. This makes debugging easier. The default setting is `+off+`. This parameter can only be set at server start.
[.term]#`+jit_dump_bitcode+` (`+boolean+`) ::
  Writes the generated LLVM IR out to the file system, inside link:runtime-config-file-locations.html#GUC-DATA-DIRECTORY[data_directory]. This is only useful for working on the internals of the JIT implementation. The default setting is `+off+`. This parameter can only be changed by a superuser.
[.term]#`+jit_expressions+` (`+boolean+`) ::
  Determines whether expressions are JIT compiled, when JIT compilation is activated (see link:jit-decision.html[Section 31.2]). The default is `+on+`.
[.term]#`+jit_profiling_support+` (`+boolean+`) ::
  If LLVM has the required functionality, emit the data needed to allow perf to profile functions generated by JIT. This writes out files to `+$HOME/.debug/jit/+`; the user is responsible for performing cleanup when desired. The default setting is `+off+`. This parameter can only be set at server start.
[.term]#`+jit_tuple_deforming+` (`+boolean+`) ::
  Determines whether tuple deforming is JIT compiled, when JIT compilation is activated (see link:jit-decision.html[Section 31.2]). The default is `+on+`.