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Overview
| Comment: | Updated comments. No code changes. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | auto-analyze |
| Files: | files | file ages | folders |
| SHA1: |
e842ad391e62df273a5b1ed569d42ea4 |
| User & Date: | drh 2017-02-18 22:52:40.654 |
Context
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2017-02-20
| ||
| 13:11 | Merge fixes from trunk. (check-in: ff213f2ef5 user: drh tags: auto-analyze) | |
|
2017-02-18
| ||
| 22:52 | Updated comments. No code changes. (check-in: e842ad391e user: drh tags: auto-analyze) | |
| 15:58 | Add the OP_SqlExec opcode and use it to implement "PRAGMA analyze_as_needed", invoking ANALYZE subcommands as necessary. This simplifies the implementation. (check-in: d386015f5e user: drh tags: auto-analyze) | |
Changes
Changes to src/pragma.c.
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case PragTyp_SHRINK_MEMORY: {
sqlite3_db_release_memory(db);
break;
}
/*
** PRAGMA analyze_as_needed
*/
case PragTyp_ANALYZE_AS_NEEDED: {
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case PragTyp_SHRINK_MEMORY: {
sqlite3_db_release_memory(db);
break;
}
/*
** PRAGMA analyze_as_needed
** PRAGMA schema.analyze_as_needed
**
** This pragma runs ANALYZE on any tables which would have benefitted
** from having recent statistics at some point since the start of the
** current connection. Only tables in "schema" are analyzed in the
** second form. In the first form, all tables except TEMP tables are
** checked.
**
** A table is analyzed only if both of the following are true:
**
** (1) The query planner used sqlite_stat1-style statistics for one or
** more indexes of the table at some point during the lifetime of
** the current connection.
**
** (2) One or more indexes of the table are currently unanalyzed OR
** the number of rows in the table has increased by 25 times or more
** since the last time ANALYZE was run.
*/
case PragTyp_ANALYZE_AS_NEEDED: {
int iDbLast; /* Loop termination point for the schema loop */
int iTabCur; /* Cursor for a table whose size needs checking */
HashElem *k; /* Loop over tables of a schema */
Schema *pSchema; /* The current schema */
Table *pTab; /* A table in the schema */
Index *pIdx; /* An index of the table */
LogEst szThreshold; /* Size threshold above which reanalysis is needd */
char *zSubSql; /* SQL statement for the OP_SqlExec opcode */
iTabCur = pParse->nTab++;
for(iDbLast = zDb?iDb:db->nDb-1; iDb<=iDbLast; iDb++){
if( iDb==1 ) continue;
sqlite3CodeVerifySchema(pParse, iDb);
pSchema = db->aDb[iDb].pSchema;
for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
pTab = (Table*)sqliteHashData(k);
/* If table pTab has not been used in a way that would benefit from
** having analysis statistics during the current session, then skip it.
** This also has the effect of skipping virtual tables and views */
if( (pTab->tabFlags & TF_StatsUsed)==0 ) continue;
/* Reanalyze if the table is 25 times larger than the last analysis */
szThreshold = pTab->nRowLogEst + 46; assert( sqlite3LogEst(25)==46 );
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
if( !pIdx->hasStat1 ){
szThreshold = 0; /* Always analyze if any index lacks statistics */
break;
}
}
if( szThreshold ){
sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
sqlite3VdbeAddOp3(v, OP_IfSmaller, iTabCur,
sqlite3VdbeCurrentAddr(v)+2, szThreshold);
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