4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
11 *************************************************************************
13 ** This module implements the sqlite3_status() interface and related
16 ** $Id: status.c,v 1.9 2008/09/02 00:52:52 drh Exp $
18 #include "sqliteInt.h"
21 ** Variables in which to record status information.
23 typedef struct sqlite3StatType sqlite3StatType;
24 static SQLITE_WSD struct sqlite3StatType {
25 int nowValue[9]; /* Current value */
26 int mxValue[9]; /* Maximum value */
27 } sqlite3Stat = { {0,}, {0,} };
30 /* The "wsdStat" macro will resolve to the status information
31 ** state vector. If writable static data is unsupported on the target,
32 ** we have to locate the state vector at run-time. In the more common
33 ** case where writable static data is supported, wsdStat can refer directly
34 ** to the "sqlite3Stat" state vector declared above.
36 #ifdef SQLITE_OMIT_WSD
37 # define wsdStatInit sqlite3StatType *x = &GLOBAL(sqlite3StatType,sqlite3Stat)
41 # define wsdStat sqlite3Stat
45 ** Return the current value of a status parameter.
47 int sqlite3StatusValue(int op){
49 assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
50 return wsdStat.nowValue[op];
54 ** Add N to the value of a status record. It is assumed that the
55 ** caller holds appropriate locks.
57 void sqlite3StatusAdd(int op, int N){
59 assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
60 wsdStat.nowValue[op] += N;
61 if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){
62 wsdStat.mxValue[op] = wsdStat.nowValue[op];
67 ** Set the value of a status to X.
69 void sqlite3StatusSet(int op, int X){
71 assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
72 wsdStat.nowValue[op] = X;
73 if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){
74 wsdStat.mxValue[op] = wsdStat.nowValue[op];
79 ** Query status information.
81 ** This implementation assumes that reading or writing an aligned
82 ** 32-bit integer is an atomic operation. If that assumption is not true,
83 ** then this routine is not threadsafe.
85 SQLITE_EXPORT int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag){
87 if( op<0 || op>=ArraySize(wsdStat.nowValue) ){
90 *pCurrent = wsdStat.nowValue[op];
91 *pHighwater = wsdStat.mxValue[op];
93 wsdStat.mxValue[op] = wsdStat.nowValue[op];
99 ** Query status information for a single database connection
101 SQLITE_EXPORT int sqlite3_db_status(
102 sqlite3 *db, /* The database connection whose status is desired */
103 int op, /* Status verb */
104 int *pCurrent, /* Write current value here */
105 int *pHighwater, /* Write high-water mark here */
106 int resetFlag /* Reset high-water mark if true */
109 case SQLITE_DBSTATUS_LOOKASIDE_USED: {
110 *pCurrent = db->lookaside.nOut;
111 *pHighwater = db->lookaside.mxOut;
113 db->lookaside.mxOut = db->lookaside.nOut;