Improve the speed of OP_Column through better caching. (CVS 1577)
FossilOrigin-Name: f687977a28eda5ce0aa1cba2fdfb0152443032bc
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drh
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16
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@ -1,5 +1,5 @@
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C Fix\stypo\sin\sthe\slocking\sdocument.\s(CVS\s1576)
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D 2004-06-12T14:11:38
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C Improve\sthe\sspeed\sof\sOP_Column\sthrough\sbetter\scaching.\s(CVS\s1577)
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D 2004-06-12T18:12:16
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F Makefile.in ab7b0d5118e2da97bac66be8684a1034e3500f5a
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F Makefile.linux-gcc a9e5a0d309fa7c38e7c14d3ecf7690879d3a5457
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F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
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@ -41,7 +41,7 @@ F src/legacy.c ad23746f15f67e34577621b1875f639c94839e1f
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F src/main.c 9061fff2b04759d849155a334bf2a9f158d325d7
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F src/md5.c d77a389955759c8329bb357e3d71bac3d6eb710b
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F src/os.h 23c69c5084e71b5fe199ff1c4e35a4aded0f1380
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F src/os_common.h 6393ac67a3a7b4aea19ff17529980ecf77eb2348
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F src/os_common.h ba1b7306e16e2091718f2c48db0fe6c1d7a31bb8
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F src/os_mac.c b823874690615ace0dd520d3ad1fe8bfd864b7e0
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F src/os_mac.h 51d2445f47e182ed32d3bd6937f81070c6fd9bd4
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F src/os_unix.c 7ece785e36c4ecb57c73db8d374b56912d742c4a
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@ -71,9 +71,9 @@ F src/update.c 168b6d523087ca4545b74ec9f3102b1f3c6b1e38
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F src/utf.c e16737b3fc4201bf7ce9bd8ced5250596aa31b76
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F src/util.c 90375fa253137562d536ccdd40b297f0fd7413fc
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F src/vacuum.c b921eb778842592e1fb48a9d4cef7e861103878f
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F src/vdbe.c 026b78bc404a2585aaefbf876295ed3ae892d769
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F src/vdbe.c 9f941bbdf0bcbc18fbdfceecbc2322e82084e094
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F src/vdbe.h 46f74444a213129bc4b5ce40124dd8ed613b0cde
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F src/vdbeInt.h c4ff480cd8f859c9862d759aebd0fe5ebaef47a1
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F src/vdbeInt.h 1cc767a63eefd1d1114e190336588c6d4f70a6a0
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F src/vdbeapi.c ee350b552fc4c1c695b760f914f69e9c5556e829
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F src/vdbeaux.c 1d0dbaf73c89bd1cc27abad19ee0aa26ab5d03f4
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F src/vdbemem.c 34f59988831ea032b7f526c2c73175f9f4c0f3ad
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@ -223,7 +223,7 @@ F www/support.tcl 1801397edd271cc39a2aadd54e701184b5181248
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F www/tclsqlite.tcl 19191cf2a1010eaeff74c51d83fd5f5a4d899075
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F www/vdbe.tcl 59288db1ac5c0616296b26dce071c36cb611dfe9
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F www/whentouse.tcl a8335bce47cc2fddb07f19052cb0cb4d9129a8e4
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P 5903f53828b5d282b33e27813417e4317c9ecf0b
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R a46c51da808bad8e24d7946d300b2226
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P 99a7bd83ac38e14bb936a834634313cf98279a62
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R 1e1692dcb3026c03937468eb4d723051
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U drh
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Z e597c81eeb6dd60916f877dd834b0e9c
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Z 511db11f04adc59072cae9559d18a6b6
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@ -1 +1 @@
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99a7bd83ac38e14bb936a834634313cf98279a62
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f687977a28eda5ce0aa1cba2fdfb0152443032bc
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@ -24,7 +24,7 @@
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** on i486 hardware.
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*/
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int sqlite3_os_trace = 0;
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#if 1
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#ifdef SQLITE_DEBUG
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static int last_page = 0;
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__inline__ unsigned long long int hwtime(void){
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unsigned long long int x;
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40
src/vdbe.c
40
src/vdbe.c
@ -43,7 +43,7 @@
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** in this file for details. If in doubt, do not deviate from existing
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** commenting and indentation practices when changing or adding code.
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**
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** $Id: vdbe.c,v 1.368 2004/06/12 09:25:25 danielk1977 Exp $
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** $Id: vdbe.c,v 1.369 2004/06/12 18:12:16 drh Exp $
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*/
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#include "sqliteInt.h"
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#include "os.h"
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@ -1899,7 +1899,7 @@ case OP_Column: {
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int p1 = pOp->p1; /* P1 value of the opcode */
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int p2 = pOp->p2; /* column number to retrieve */
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Cursor *pC = 0; /* The VDBE cursor */
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char *zRec; /* Pointer to record-data from stack or pseudo-table. */
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char *zRec; /* Pointer to complete record-data */
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BtCursor *pCrsr; /* The BTree cursor */
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u32 *aType; /* aType[i] holds the numeric type of the i-th column */
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u32 *aOffset; /* aOffset[i] is offset to start of data for i-th column */
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@ -1916,9 +1916,15 @@ case OP_Column: {
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assert( p1<p->nCursor );
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pTos++;
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/* This block sets the variable payloadSize, and if the data is coming
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** from the stack or from a pseudo-table zRec. If the data is coming
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** from a real cursor, then zRec is left as NULL.
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/* This block sets the variable payloadSize to be the total number of
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** bytes in the record.
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**
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** zRec is set to be the complete text of the record if it is available.
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** The complete record text is always available for pseudo-tables and
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** when we are decoded a record from the stack. If the record is stored
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** in a cursor, the complete record text might be available in the
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** pC->aRow cache. Or it might not be. If the data is unavailable,
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** zRec is set to NULL.
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**
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** We also compute the number of columns in the record. For cursors,
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** the number of columns is stored in the Cursor.nField element. For
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@ -1926,6 +1932,7 @@ case OP_Column: {
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** which is the number of records.
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*/
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if( p1<0 ){
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/* Take the record off of the stack */
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Mem *pRec = &pTos[p1];
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Mem *pCnt = &pRec[-1];
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assert( pRec>=p->aStack );
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@ -1936,6 +1943,7 @@ case OP_Column: {
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assert( pCnt->flags & MEM_Int );
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nField = pCnt->i;
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}else if( (pC = p->apCsr[p1])->pCursor!=0 ){
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/* The record is stored in a B-Tree */
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sqlite3VdbeCursorMoveto(pC);
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zRec = 0;
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pCrsr = pC->pCursor;
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@ -1943,6 +1951,7 @@ case OP_Column: {
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payloadSize = 0;
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}else if( pC->cacheValid ){
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payloadSize = pC->payloadSize;
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zRec = pC->aRow;
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}else if( pC->keyAsData ){
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i64 payloadSize64;
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sqlite3BtreeKeySize(pCrsr, &payloadSize64);
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@ -1952,6 +1961,7 @@ case OP_Column: {
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}
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nField = pC->nField;
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}else if( pC->pseudoTable ){
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/* The record is the sole entry of a pseudo-table */
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payloadSize = pC->nData;
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zRec = pC->pData;
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pC->cacheValid = 0;
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@ -1996,11 +2006,27 @@ case OP_Column: {
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}else{
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zData = (char*)sqlite3BtreeDataFetch(pCrsr, &avail);
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}
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/* If KeyFetch()/DataFetch() managed to get the entire payload,
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** save the payload in the pC->aRow cache. That will save us from
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** having to make additional calls to fetch the content portion of
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** the record.
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*/
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if( avail>=payloadSize ){
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zRec = pC->aRow = zData;
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}else{
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pC->aRow = 0;
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}
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}
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idx = sqlite3GetVarint32(zData, &szHdr);
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/* Get the complete header text */
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if( !zRec && avail<idx ){
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/* The KeyFetch() or DataFetch() above are fast and will get the entire
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** record header in most cases. But they will fail to get the complete
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** record header if the record header does not fit on a single page
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** in the B-Tree. When that happens, use sqlite3VdbeMemFromBtree() to
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** acquire the complete header text.
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*/
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if( !zRec && avail<szHdr ){
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rc = sqlite3VdbeMemFromBtree(pCrsr, 0, szHdr, pC->keyAsData, &sMem);
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if( rc!=SQLITE_OK ){
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goto abort_due_to_error;
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@ -83,11 +83,14 @@ struct Cursor {
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int nField; /* Number of fields in the header */
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/* Cached information about the header for the data record that the
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** cursor is currently pointing to */
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** cursor is currently pointing to. Only valid if cacheValid is true.
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** zRow might point to (ephemeral) data for the current row, or it might
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** be NULL. */
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Bool cacheValid; /* True if the cache is valid */
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int payloadSize; /* Total number of bytes in the record */
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u32 *aType; /* Type values for all entries in the record */
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u32 *aOffset; /* Cached offsets to the start of each columns data */
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u8 *aRow; /* Data for the current row, if all on one page */
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};
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typedef struct Cursor Cursor;
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