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Change the TCL interface so that it can cache VMs and reuse them without

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recompiling.  But for now leave the cache turned off by default. (CVS 2269)

FossilOrigin-Name: 8db6bfef52c1f35afdb8b60cba34f6807a5917f4
This commit is contained in:
drh
2005-01-24 00:28:42 +00:00
parent 4af00c6cee
commit fb7e7651ca
5 changed files with 263 additions and 58 deletions
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273
src/tclsqlite.c
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@@ -11,7 +11,7 @@
*************************************************************************
** A TCL Interface to SQLite
**
** $Id: tclsqlite.c,v 1.115 2005/01/13 23:54:32 drh Exp $
** $Id: tclsqlite.c,v 1.116 2005/01/24 00:28:43 drh Exp $
*/
#ifndef NO_TCL /* Omit this whole file if TCL is unavailable */
@@ -22,6 +22,9 @@
#include <string.h>
#include <assert.h>
#define NUM_PREPARED_STMTS 0
#define MAX_PREPARED_STMTS 100
/*
** If TCL uses UTF-8 and SQLite is configured to use iso8859, then we
** have to do a translation when going between the two. Set the
@@ -54,6 +57,19 @@ struct SqlCollate {
SqlCollate *pNext; /* Next function on the list of them all */
};
/*
** Prepared statements are cached for faster execution. Each prepared
** statement is described by an instance of the following structure.
*/
typedef struct SqlPreparedStmt SqlPreparedStmt;
struct SqlPreparedStmt {
SqlPreparedStmt *pNext; /* Next in linked list */
SqlPreparedStmt *pPrev; /* Previous on the list */
sqlite3_stmt *pStmt; /* The prepared statement */
int nSql; /* chars in zSql[] */
char zSql[1]; /* Text of the SQL statement */
};
/*
** There is one instance of this structure for each SQLite database
** that has been opened by the SQLite TCL interface.
@@ -71,14 +87,35 @@ struct SqliteDb {
SqlCollate *pCollate; /* List of SQL collation functions */
int rc; /* Return code of most recent sqlite3_exec() */
Tcl_Obj *pCollateNeeded; /* Collation needed script */
SqlPreparedStmt *stmtList; /* List of prepared statements*/
SqlPreparedStmt *stmtLast; /* Last statement in the list */
int maxStmt; /* The next maximum number of stmtList */
int nStmt; /* Number of statements in stmtList */
};
/*
** Finalize and free a list of prepared statements
*/
static void flushStmtCache( SqliteDb *pDb ){
SqlPreparedStmt *pPreStmt;
while( pDb->stmtList ){
sqlite3_finalize( pDb->stmtList->pStmt );
pPreStmt = pDb->stmtList;
pDb->stmtList = pDb->stmtList->pNext;
Tcl_Free( (char*)pPreStmt );
}
pDb->nStmt = 0;
pDb->stmtLast = 0;
}
/*
** TCL calls this procedure when an sqlite3 database command is
** deleted.
*/
static void DbDeleteCmd(void *db){
SqliteDb *pDb = (SqliteDb*)db;
flushStmtCache(pDb);
sqlite3_close(pDb->db);
while( pDb->pFunc ){
SqlFunc *pFunc = pDb->pFunc;
@@ -215,7 +252,7 @@ static int tclSqlCollate(
** This routine is called to evaluate an SQL function implemented
** using TCL script.
*/
static void tclSqlFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
static void tclSqlFunc(sqlite3_context *context, int argc, sqlite3_value**argv){
SqlFunc *p = sqlite3_user_data(context);
Tcl_DString cmd;
int i;
@@ -400,23 +437,23 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
int choice;
int rc = TCL_OK;
static const char *DB_strs[] = {
"authorizer", "busy", "changes",
"close", "collate", "collation_needed",
"commit_hook", "complete", "copy",
"errorcode", "eval", "function",
"last_insert_rowid", "onecolumn", "progress",
"rekey", "timeout", "total_changes",
"trace", "version",
"authorizer", "busy", "cache",
"changes", "close", "collate",
"collation_needed", "commit_hook", "complete",
"copy", "errorcode", "eval",
"function", "last_insert_rowid", "onecolumn",
"progress", "rekey", "timeout",
"total_changes", "trace", "version",
0
};
enum DB_enum {
DB_AUTHORIZER, DB_BUSY, DB_CHANGES,
DB_CLOSE, DB_COLLATE, DB_COLLATION_NEEDED,
DB_COMMIT_HOOK, DB_COMPLETE, DB_COPY,
DB_ERRORCODE, DB_EVAL, DB_FUNCTION,
DB_LAST_INSERT_ROWID, DB_ONECOLUMN, DB_PROGRESS,
DB_REKEY, DB_TIMEOUT, DB_TOTAL_CHANGES,
DB_TRACE, DB_VERSION
DB_AUTHORIZER, DB_BUSY, DB_CACHE,
DB_CHANGES, DB_CLOSE, DB_COLLATE,
DB_COLLATION_NEEDED, DB_COMMIT_HOOK, DB_COMPLETE,
DB_COPY, DB_ERRORCODE, DB_EVAL,
DB_FUNCTION, DB_LAST_INSERT_ROWID,DB_ONECOLUMN,
DB_PROGRESS, DB_REKEY, DB_TIMEOUT,
DB_TOTAL_CHANGES, DB_TRACE, DB_VERSION
};
/* don't leave trailing commas on DB_enum, it confuses the AIX xlc compiler */
@@ -520,6 +557,55 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
break;
}
/* $db cache flush
** $db cache size n
**
** Flush the prepared statement cache, or set the maximum number of
** cached statements.
*/
case DB_CACHE: {
char *subCmd;
int n;
if( objc<=2 ){
Tcl_WrongNumArgs(interp, 1, objv, "cache option ?arg?");
return TCL_ERROR;
}
subCmd = Tcl_GetStringFromObj( objv[2], 0 );
if( *subCmd=='f' && strcmp(subCmd,"flush")==0 ){
if( objc!=3 ){
Tcl_WrongNumArgs(interp, 2, objv, "flush");
return TCL_ERROR;
}else{
flushStmtCache( pDb );
}
}else if( *subCmd=='s' && strcmp(subCmd,"size")==0 ){
if( objc!=4 ){
Tcl_WrongNumArgs(interp, 2, objv, "size n");
return TCL_ERROR;
}else{
if( TCL_ERROR==Tcl_GetIntFromObj(interp, objv[3], &n) ){
Tcl_AppendResult( interp, "cannot convert \"",
Tcl_GetStringFromObj(objv[3],0), "\" to integer", 0);
return TCL_ERROR;
}else{
if( n<0 ){
flushStmtCache( pDb );
n = 0;
}else if( n>MAX_PREPARED_STMTS ){
n = MAX_PREPARED_STMTS;
}
pDb->maxStmt = n;
}
}
}else{
Tcl_AppendResult( interp, "bad option \"",
Tcl_GetStringFromObj(objv[0],0), "\": must be flush or size", 0);
return TCL_ERROR;
}
break;
}
/* $db changes
**
** Return the number of rows that were modified, inserted, or deleted by
@@ -689,6 +775,8 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
int nParm; /* Number of entries used in apParm[] */
Tcl_Obj *aParm[10]; /* Static space for apParm[] in the common case */
Tcl_Obj *pRet; /* Value to be returned */
SqlPreparedStmt *pPreStmt; /* Pointer to a prepared statement */
int rc2;
if( choice==DB_ONECOLUMN ){
if( objc!=3 ){
@@ -718,29 +806,78 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
Tcl_IncrRefCount(objv[2]);
zSql = Tcl_GetStringFromObj(objv[2], 0);
while( rc==TCL_OK && zSql[0] ){
int i; /* Loop counter */
int nVar; /* Number of wildcards in the SQL */
int nCol; /* Number of columns in the result set */
int i; /* Loop counter */
int nVar; /* Number of bind parameters in the pStmt */
int nCol; /* Number of columns in the result set */
Tcl_Obj **apColName = 0; /* Array of column names */
int len; /* String length of zSql */
/* Compile a single SQL statement */
if( SQLITE_OK!=sqlite3_prepare(pDb->db, zSql, -1, &pStmt, &zLeft) ){
Tcl_SetObjResult(interp, dbTextToObj(sqlite3_errmsg(pDb->db)));
rc = TCL_ERROR;
break;
/* Try to find a SQL statement that has already been compiled and
** which matches the next sequence of SQL.
*/
pStmt = 0;
pPreStmt = pDb->stmtList;
len = strlen(zSql);
if( pPreStmt && sqlite3_expired(pPreStmt->pStmt) ){
flushStmtCache(pDb);
pPreStmt = 0;
}
for(; pPreStmt; pPreStmt=pPreStmt->pNext){
int n = pPreStmt->nSql;
if( len>=n
&& memcmp(pPreStmt->zSql, zSql, n)==0
&& (zSql[n]==0 || zSql[n-1]==';')
){
pStmt = pPreStmt->pStmt;
zLeft = &zSql[pPreStmt->nSql];
/* When a prepared statement is found, unlink it from the
** cache list. It will later be added back to the beginning
** of the cache list in order to implement LRU replacement.
*/
if( pPreStmt->pPrev ){
pPreStmt->pPrev->pNext = pPreStmt->pNext;
}else{
pDb->stmtList = pPreStmt->pNext;
}
if( pPreStmt->pNext ){
pPreStmt->pNext->pPrev = pPreStmt->pPrev;
}else{
pDb->stmtLast = pPreStmt->pPrev;
}
pDb->nStmt--;
break;
}
}
/* If no prepared statement was found. Compile the SQL text
*/
if( pStmt==0 ){
if( SQLITE_OK!=sqlite3_errcode(pDb->db) ){
if( SQLITE_OK!=sqlite3_prepare(pDb->db, zSql, -1, &pStmt, &zLeft) ){
Tcl_SetObjResult(interp, dbTextToObj(sqlite3_errmsg(pDb->db)));
rc = TCL_ERROR;
break;
}else{
zSql = zLeft;
continue;
}
if( pStmt==0 ){
if( SQLITE_OK!=sqlite3_errcode(pDb->db) ){
/* A compile-time error in the statement
*/
Tcl_SetObjResult(interp, dbTextToObj(sqlite3_errmsg(pDb->db)));
rc = TCL_ERROR;
break;
}else{
/* The statement was a no-op. Continue to the next statement
** in the SQL string.
*/
zSql = zLeft;
continue;
}
}
assert( pPreStmt==0 );
}
/* Bind values to wildcards that begin with $ or : */
/* Bind values to parameters that begin with $ or :
*/
nVar = sqlite3_bind_parameter_count(pStmt);
nParm = 0;
if( nVar>sizeof(aParm)/sizeof(aParm[0]) ){
@@ -776,6 +913,8 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
Tcl_IncrRefCount(pVar);
apParm[nParm++] = pVar;
}
}else{
sqlite3_bind_null( pStmt, i );
}
}
}
@@ -880,19 +1019,75 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
Tcl_Free((char*)apParm);
}
/* Finalize the statement. If the result code is SQLITE_SCHEMA, then
** try again to execute the same statement
/* Reset the statement. If the result code is SQLITE_SCHEMA, then
** flush the statement cache and try the statement again.
*/
if( SQLITE_SCHEMA==sqlite3_finalize(pStmt) ){
rc2 = sqlite3_reset(pStmt);
if( SQLITE_SCHEMA==rc2 ){
/* After a schema change, flush the cache and try to run the
** statement again
*/
flushStmtCache( pDb );
sqlite3_finalize(pStmt);
if( pPreStmt ) Tcl_Free((char*)pPreStmt);
continue;
}
if( SQLITE_OK!=sqlite3_errcode(pDb->db) ){
}else if( SQLITE_OK!=rc2 ){
/* If a run-time error occurs, report the error and stop reading
** the SQL
*/
Tcl_SetObjResult(interp, dbTextToObj(sqlite3_errmsg(pDb->db)));
sqlite3_finalize(pStmt);
rc = TCL_ERROR;
if( pPreStmt ) Tcl_Free((char*)pPreStmt);
break;
}else if( pDb->maxStmt<=0 ){
/* If the cache is turned off, deallocated the statement */
if( pPreStmt ) Tcl_Free((char*)pPreStmt);
sqlite3_finalize(pStmt);
}else{
/* Everything worked and the cache is operational.
** Create a new SqlPreparedStmt structure if we need one.
** (If we already have one we can just reuse it.)
*/
if( pPreStmt==0 ){
len = zLeft - zSql;
pPreStmt = (SqlPreparedStmt*)Tcl_Alloc( sizeof(*pPreStmt) + len );
if( pPreStmt==0 ) return TCL_ERROR;
pPreStmt->pStmt = pStmt;
pPreStmt->nSql = len;
memcpy(pPreStmt->zSql, zSql, len);
pPreStmt->zSql[len] = 0;
}
/* Add the prepared statement to the beginning of the cache list
*/
pPreStmt->pNext = pDb->stmtList;
pPreStmt->pPrev = 0;
if( pDb->stmtList ){
pDb->stmtList->pPrev = pPreStmt;
}
pDb->stmtList = pPreStmt;
if( pDb->stmtLast==0 ){
assert( pDb->nStmt==0 );
pDb->stmtLast = pPreStmt;
}else{
assert( pDb->nStmt>0 );
}
pDb->nStmt++;
/* If we have too many statement in cache, remove the surplus from the
** end of the cache list.
*/
while( pDb->nStmt>pDb->maxStmt ){
sqlite3_finalize(pDb->stmtLast->pStmt);
pDb->stmtLast = pDb->stmtLast->pPrev;
Tcl_Free((char*)pDb->stmtLast->pNext);
pDb->stmtLast->pNext = 0;
pDb->nStmt--;
}
}
/* Proceed to the next statement */
zSql = zLeft;
}
Tcl_DecrRefCount(objv[2]);
@@ -932,7 +1127,12 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
strcpy(pFunc->zScript, zScript);
rc = sqlite3_create_function(pDb->db, zName, -1, SQLITE_UTF8,
pFunc, tclSqlFunc, 0, 0);
if( rc!=SQLITE_OK ) rc = TCL_ERROR;
if( rc!=SQLITE_OK ){
rc = TCL_ERROR;
}else{
/* Must flush any cached statements */
flushStmtCache( pDb );
}
break;
}
@@ -1395,6 +1595,7 @@ static int DbMain(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
free(zErrMsg);
return TCL_ERROR;
}
p->maxStmt = NUM_PREPARED_STMTS;
zArg = Tcl_GetStringFromObj(objv[1], 0);
Tcl_CreateObjCommand(interp, zArg, DbObjCmd, (char*)p, DbDeleteCmd);