124 lines
5.2 KiB
Groff
124 lines
5.2 KiB
Groff
.Dd March 11, 2017
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.Dt SQLITE_DBSTATUS_LOOKASIDE_USED 3
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.Os
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.Sh NAME
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.Nm SQLITE_DBSTATUS_LOOKASIDE_USED ,
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.Nm SQLITE_DBSTATUS_CACHE_USED ,
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.Nm SQLITE_DBSTATUS_SCHEMA_USED ,
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.Nm SQLITE_DBSTATUS_STMT_USED ,
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.Nm SQLITE_DBSTATUS_LOOKASIDE_HIT ,
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.Nm SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE ,
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.Nm SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL ,
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.Nm SQLITE_DBSTATUS_CACHE_HIT ,
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.Nm SQLITE_DBSTATUS_CACHE_MISS ,
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.Nm SQLITE_DBSTATUS_CACHE_WRITE ,
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.Nm SQLITE_DBSTATUS_DEFERRED_FKS ,
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.Nm SQLITE_DBSTATUS_CACHE_USED_SHARED ,
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.Nm SQLITE_DBSTATUS_MAX
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.Nd Status Parameters for database connections
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.Sh SYNOPSIS
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.Fd #define SQLITE_DBSTATUS_LOOKASIDE_USED
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.Fd #define SQLITE_DBSTATUS_CACHE_USED
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.Fd #define SQLITE_DBSTATUS_SCHEMA_USED
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.Fd #define SQLITE_DBSTATUS_STMT_USED
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.Fd #define SQLITE_DBSTATUS_LOOKASIDE_HIT
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.Fd #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE
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.Fd #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL
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.Fd #define SQLITE_DBSTATUS_CACHE_HIT
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.Fd #define SQLITE_DBSTATUS_CACHE_MISS
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.Fd #define SQLITE_DBSTATUS_CACHE_WRITE
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.Fd #define SQLITE_DBSTATUS_DEFERRED_FKS
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.Fd #define SQLITE_DBSTATUS_CACHE_USED_SHARED
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.Fd #define SQLITE_DBSTATUS_MAX
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.Sh DESCRIPTION
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These constants are the available integer "verbs" that can be passed
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as the second argument to the sqlite3_db_status()
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interface.
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.Pp
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New verbs may be added in future releases of SQLite.
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Existing verbs might be discontinued.
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Applications should check the return code from sqlite3_db_status()
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to make sure that the call worked.
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The sqlite3_db_status() interface will return a
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non-zero error code if a discontinued or unsupported verb is invoked.
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.Bl -tag -width Ds
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.It SQLITE_DBSTATUS_LOOKASIDE_USED
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This parameter returns the number of lookaside memory slots currently
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checked out.
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.It SQLITE_DBSTATUS_LOOKASIDE_HIT
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This parameter returns the number malloc attempts that were satisfied
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using lookaside memory.
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Only the high-water value is meaningful; the current value is always
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zero.
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.It SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE
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This parameter returns the number malloc attempts that might have been
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satisfied using lookaside memory but failed due to the amount of memory
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requested being larger than the lookaside slot size.
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Only the high-water value is meaningful; the current value is always
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zero.
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.It SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL
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This parameter returns the number malloc attempts that might have been
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satisfied using lookaside memory but failed due to all lookaside memory
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already being in use.
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Only the high-water value is meaningful; the current value is always
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zero.
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.It SQLITE_DBSTATUS_CACHE_USED
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This parameter returns the approximate number of bytes of heap memory
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used by all pager caches associated with the database connection.
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The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always
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0.
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.It SQLITE_DBSTATUS_CACHE_USED_SHARED
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This parameter is similar to DBSTATUS_CACHE_USED, except that if a
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pager cache is shared between two or more connections the bytes of
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heap memory used by that pager cache is divided evenly between the
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attached connections.
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In other words, if none of the pager caches associated with the database
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connection are shared, this request returns the same value as DBSTATUS_CACHE_USED.
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Or, if one or more or the pager caches are shared, the value returned
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by this call will be smaller than that returned by DBSTATUS_CACHE_USED.
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The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED_SHARED
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is always 0.
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.It SQLITE_DBSTATUS_SCHEMA_USED
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This parameter returns the approximate number of bytes of heap memory
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used to store the schema for all databases associated with the connection
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- main, temp, and any ATTACH-ed databases.
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The full amount of memory used by the schemas is reported, even if
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the schema memory is shared with other database connections due to
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shared cache mode being enabled.
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The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always
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0.
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.It SQLITE_DBSTATUS_STMT_USED
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This parameter returns the approximate number of bytes of heap and
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lookaside memory used by all prepared statements associated with the
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database connection.
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The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always
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0.
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.It SQLITE_DBSTATUS_CACHE_HIT
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This parameter returns the number of pager cache hits that have occurred.
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The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT is always
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0.
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.It SQLITE_DBSTATUS_CACHE_MISS
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This parameter returns the number of pager cache misses that have occurred.
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The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS is always
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0.
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.It SQLITE_DBSTATUS_CACHE_WRITE
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This parameter returns the number of dirty cache entries that have
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been written to disk.
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Specifically, the number of pages written to the wal file in wal mode
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databases, or the number of pages written to the database file in rollback
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mode databases.
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Any pages written as part of transaction rollback or database recovery
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operations are not included.
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If an IO or other error occurs while writing a page to disk, the effect
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on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.
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The highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always
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0.
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.It SQLITE_DBSTATUS_DEFERRED_FKS
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This parameter returns zero for the current value if and only if all
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foreign key constraints (deferred or immediate) have been resolved.
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The highwater mark is always 0.
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.El
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.Pp
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.Sh SEE ALSO
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.Xr sqlite3_db_status 3
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