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Diffstat (limited to 'ext/misc/memstat.c')
| -rw-r--r-- | ext/misc/memstat.c | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/ext/misc/memstat.c b/ext/misc/memstat.c new file mode 100644 index 0000000..800a86e --- /dev/null +++ b/ext/misc/memstat.c @@ -0,0 +1,428 @@ +/* +** 2018-09-27 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +************************************************************************* +** +** This file demonstrates an eponymous virtual table that returns information +** from sqlite3_status64() and sqlite3_db_status(). +** +** Usage example: +** +** .load ./memstat +** .mode quote +** .header on +** SELECT * FROM memstat; +*/ +#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_MEMSTATVTAB) +#if !defined(SQLITEINT_H) +#include "sqlite3ext.h" +#endif +SQLITE_EXTENSION_INIT1 +#include <assert.h> +#include <string.h> + +#ifndef SQLITE_OMIT_VIRTUALTABLE + +/* memstat_vtab is a subclass of sqlite3_vtab which will +** serve as the underlying representation of a memstat virtual table +*/ +typedef struct memstat_vtab memstat_vtab; +struct memstat_vtab { + sqlite3_vtab base; /* Base class - must be first */ + sqlite3 *db; /* Database connection for this memstat vtab */ +}; + +/* memstat_cursor is a subclass of sqlite3_vtab_cursor which will +** serve as the underlying representation of a cursor that scans +** over rows of the result +*/ +typedef struct memstat_cursor memstat_cursor; +struct memstat_cursor { + sqlite3_vtab_cursor base; /* Base class - must be first */ + sqlite3 *db; /* Database connection for this cursor */ + int iRowid; /* Current row in aMemstatColumn[] */ + int iDb; /* Which schema we are looking at */ + int nDb; /* Number of schemas */ + char **azDb; /* Names of all schemas */ + sqlite3_int64 aVal[2]; /* Result values */ +}; + +/* +** The memstatConnect() method is invoked to create a new +** memstat_vtab that describes the memstat virtual table. +** +** Think of this routine as the constructor for memstat_vtab objects. +** +** All this routine needs to do is: +** +** (1) Allocate the memstat_vtab object and initialize all fields. +** +** (2) Tell SQLite (via the sqlite3_declare_vtab() interface) what the +** result set of queries against memstat will look like. +*/ +static int memstatConnect( + sqlite3 *db, + void *pAux, + int argc, const char *const*argv, + sqlite3_vtab **ppVtab, + char **pzErr +){ + memstat_vtab *pNew; + int rc; + +/* Column numbers */ +#define MSV_COLUMN_NAME 0 /* Name of quantity being measured */ +#define MSV_COLUMN_SCHEMA 1 /* schema name */ +#define MSV_COLUMN_VALUE 2 /* Current value */ +#define MSV_COLUMN_HIWTR 3 /* Highwater mark */ + + rc = sqlite3_declare_vtab(db,"CREATE TABLE x(name,schema,value,hiwtr)"); + if( rc==SQLITE_OK ){ + pNew = sqlite3_malloc( sizeof(*pNew) ); + *ppVtab = (sqlite3_vtab*)pNew; + if( pNew==0 ) return SQLITE_NOMEM; + memset(pNew, 0, sizeof(*pNew)); + pNew->db = db; + } + return rc; +} + +/* +** This method is the destructor for memstat_cursor objects. +*/ +static int memstatDisconnect(sqlite3_vtab *pVtab){ + sqlite3_free(pVtab); + return SQLITE_OK; +} + +/* +** Constructor for a new memstat_cursor object. +*/ +static int memstatOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){ + memstat_cursor *pCur; + pCur = sqlite3_malloc( sizeof(*pCur) ); + if( pCur==0 ) return SQLITE_NOMEM; + memset(pCur, 0, sizeof(*pCur)); + pCur->db = ((memstat_vtab*)p)->db; + *ppCursor = &pCur->base; + return SQLITE_OK; +} + +/* +** Clear all the schema names from a cursor +*/ +static void memstatClearSchema(memstat_cursor *pCur){ + int i; + if( pCur->azDb==0 ) return; + for(i=0; i<pCur->nDb; i++){ + sqlite3_free(pCur->azDb[i]); + } + sqlite3_free(pCur->azDb); + pCur->azDb = 0; + pCur->nDb = 0; +} + +/* +** Fill in the azDb[] array for the cursor. +*/ +static int memstatFindSchemas(memstat_cursor *pCur){ + sqlite3_stmt *pStmt = 0; + int rc; + if( pCur->nDb ) return SQLITE_OK; + rc = sqlite3_prepare_v2(pCur->db, "PRAGMA database_list", -1, &pStmt, 0); + if( rc ){ + sqlite3_finalize(pStmt); + return rc; + } + while( sqlite3_step(pStmt)==SQLITE_ROW ){ + char **az, *z; + az = sqlite3_realloc64(pCur->azDb, sizeof(char*)*(pCur->nDb+1)); + if( az==0 ){ + memstatClearSchema(pCur); + return SQLITE_NOMEM; + } + pCur->azDb = az; + z = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 1)); + if( z==0 ){ + memstatClearSchema(pCur); + return SQLITE_NOMEM; + } + pCur->azDb[pCur->nDb] = z; + pCur->nDb++; + } + sqlite3_finalize(pStmt); + return SQLITE_OK; +} + + +/* +** Destructor for a memstat_cursor. +*/ +static int memstatClose(sqlite3_vtab_cursor *cur){ + memstat_cursor *pCur = (memstat_cursor*)cur; + memstatClearSchema(pCur); + sqlite3_free(cur); + return SQLITE_OK; +} + + +/* +** Allowed values for aMemstatColumn[].eType +*/ +#define MSV_GSTAT 0 /* sqlite3_status64() information */ +#define MSV_DB 1 /* sqlite3_db_status() information */ +#define MSV_ZIPVFS 2 /* ZIPVFS file-control with 64-bit return */ + +/* +** An array of quantities that can be measured and reported by +** this virtual table +*/ +static const struct MemstatColumns { + const char *zName; /* Symbolic name */ + unsigned char eType; /* Type of interface */ + unsigned char mNull; /* Bitmask of which columns are NULL */ + /* 2: dbname, 4: current, 8: hiwtr */ + int eOp; /* Opcode */ +} aMemstatColumn[] = { + {"MEMORY_USED", MSV_GSTAT, 2, SQLITE_STATUS_MEMORY_USED }, + {"MALLOC_SIZE", MSV_GSTAT, 6, SQLITE_STATUS_MALLOC_SIZE }, + {"MALLOC_COUNT", MSV_GSTAT, 2, SQLITE_STATUS_MALLOC_COUNT }, + {"PAGECACHE_USED", MSV_GSTAT, 2, SQLITE_STATUS_PAGECACHE_USED }, + {"PAGECACHE_OVERFLOW", MSV_GSTAT, 2, SQLITE_STATUS_PAGECACHE_OVERFLOW }, + {"PAGECACHE_SIZE", MSV_GSTAT, 6, SQLITE_STATUS_PAGECACHE_SIZE }, + {"PARSER_STACK", MSV_GSTAT, 6, SQLITE_STATUS_PARSER_STACK }, + {"DB_LOOKASIDE_USED", MSV_DB, 2, SQLITE_DBSTATUS_LOOKASIDE_USED }, + {"DB_LOOKASIDE_HIT", MSV_DB, 6, SQLITE_DBSTATUS_LOOKASIDE_HIT }, + {"DB_LOOKASIDE_MISS_SIZE", MSV_DB, 6, SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE}, + {"DB_LOOKASIDE_MISS_FULL", MSV_DB, 6, SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL}, + {"DB_CACHE_USED", MSV_DB, 10, SQLITE_DBSTATUS_CACHE_USED }, +#if SQLITE_VERSION_NUMBER >= 3140000 + {"DB_CACHE_USED_SHARED", MSV_DB, 10, SQLITE_DBSTATUS_CACHE_USED_SHARED }, +#endif + {"DB_SCHEMA_USED", MSV_DB, 10, SQLITE_DBSTATUS_SCHEMA_USED }, + {"DB_STMT_USED", MSV_DB, 10, SQLITE_DBSTATUS_STMT_USED }, + {"DB_CACHE_HIT", MSV_DB, 10, SQLITE_DBSTATUS_CACHE_HIT }, + {"DB_CACHE_MISS", MSV_DB, 10, SQLITE_DBSTATUS_CACHE_MISS }, + {"DB_CACHE_WRITE", MSV_DB, 10, SQLITE_DBSTATUS_CACHE_WRITE }, +#if SQLITE_VERSION_NUMBER >= 3230000 + {"DB_CACHE_SPILL", MSV_DB, 10, SQLITE_DBSTATUS_CACHE_SPILL }, +#endif + {"DB_DEFERRED_FKS", MSV_DB, 10, SQLITE_DBSTATUS_DEFERRED_FKS }, +#ifdef SQLITE_ENABLE_ZIPVFS + {"ZIPVFS_CACHE_USED", MSV_ZIPVFS, 8, 231454 }, + {"ZIPVFS_CACHE_HIT", MSV_ZIPVFS, 8, 231455 }, + {"ZIPVFS_CACHE_MISS", MSV_ZIPVFS, 8, 231456 }, + {"ZIPVFS_CACHE_WRITE", MSV_ZIPVFS, 8, 231457 }, + {"ZIPVFS_DIRECT_READ", MSV_ZIPVFS, 8, 231458 }, + {"ZIPVFS_DIRECT_BYTES", MSV_ZIPVFS, 8, 231459 }, +#endif /* SQLITE_ENABLE_ZIPVFS */ +}; +#define MSV_NROW (sizeof(aMemstatColumn)/sizeof(aMemstatColumn[0])) + +/* +** Advance a memstat_cursor to its next row of output. +*/ +static int memstatNext(sqlite3_vtab_cursor *cur){ + memstat_cursor *pCur = (memstat_cursor*)cur; + int i; + assert( pCur->iRowid<=MSV_NROW ); + while(1){ + i = (int)pCur->iRowid - 1; + if( i<0 || (aMemstatColumn[i].mNull & 2)!=0 || (++pCur->iDb)>=pCur->nDb ){ + pCur->iRowid++; + if( pCur->iRowid>MSV_NROW ) return SQLITE_OK; /* End of the table */ + pCur->iDb = 0; + i++; + } + pCur->aVal[0] = 0; + pCur->aVal[1] = 0; + switch( aMemstatColumn[i].eType ){ + case MSV_GSTAT: { + if( sqlite3_libversion_number()>=3010000 ){ + sqlite3_status64(aMemstatColumn[i].eOp, + &pCur->aVal[0], &pCur->aVal[1],0); + }else{ + int xCur, xHiwtr; + sqlite3_status(aMemstatColumn[i].eOp, &xCur, &xHiwtr, 0); + pCur->aVal[0] = xCur; + pCur->aVal[1] = xHiwtr; + } + break; + } + case MSV_DB: { + int xCur, xHiwtr; + sqlite3_db_status(pCur->db, aMemstatColumn[i].eOp, &xCur, &xHiwtr, 0); + pCur->aVal[0] = xCur; + pCur->aVal[1] = xHiwtr; + break; + } + case MSV_ZIPVFS: { + int rc; + rc = sqlite3_file_control(pCur->db, pCur->azDb[pCur->iDb], + aMemstatColumn[i].eOp, (void*)&pCur->aVal[0]); + if( rc!=SQLITE_OK ) continue; + break; + } + } + break; + } + return SQLITE_OK; +} + + +/* +** Return values of columns for the row at which the memstat_cursor +** is currently pointing. +*/ +static int memstatColumn( + sqlite3_vtab_cursor *cur, /* The cursor */ + sqlite3_context *ctx, /* First argument to sqlite3_result_...() */ + int iCol /* Which column to return */ +){ + memstat_cursor *pCur = (memstat_cursor*)cur; + int i; + assert( pCur->iRowid>0 && pCur->iRowid<=MSV_NROW ); + i = (int)pCur->iRowid - 1; + if( (aMemstatColumn[i].mNull & (1<<iCol))!=0 ){ + return SQLITE_OK; + } + switch( iCol ){ + case MSV_COLUMN_NAME: { + sqlite3_result_text(ctx, aMemstatColumn[i].zName, -1, SQLITE_STATIC); + break; + } + case MSV_COLUMN_SCHEMA: { + sqlite3_result_text(ctx, pCur->azDb[pCur->iDb], -1, 0); + break; + } + case MSV_COLUMN_VALUE: { + sqlite3_result_int64(ctx, pCur->aVal[0]); + break; + } + case MSV_COLUMN_HIWTR: { + sqlite3_result_int64(ctx, pCur->aVal[1]); + break; + } + } + return SQLITE_OK; +} + +/* +** Return the rowid for the current row. In this implementation, the +** rowid is the same as the output value. +*/ +static int memstatRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){ + memstat_cursor *pCur = (memstat_cursor*)cur; + *pRowid = pCur->iRowid*1000 + pCur->iDb; + return SQLITE_OK; +} + +/* +** Return TRUE if the cursor has been moved off of the last +** row of output. +*/ +static int memstatEof(sqlite3_vtab_cursor *cur){ + memstat_cursor *pCur = (memstat_cursor*)cur; + return pCur->iRowid>MSV_NROW; +} + +/* +** This method is called to "rewind" the memstat_cursor object back +** to the first row of output. This method is always called at least +** once prior to any call to memstatColumn() or memstatRowid() or +** memstatEof(). +*/ +static int memstatFilter( + sqlite3_vtab_cursor *pVtabCursor, + int idxNum, const char *idxStr, + int argc, sqlite3_value **argv +){ + memstat_cursor *pCur = (memstat_cursor *)pVtabCursor; + int rc = memstatFindSchemas(pCur); + if( rc ) return rc; + pCur->iRowid = 0; + pCur->iDb = 0; + return memstatNext(pVtabCursor); +} + +/* +** SQLite will invoke this method one or more times while planning a query +** that uses the memstat virtual table. This routine needs to create +** a query plan for each invocation and compute an estimated cost for that +** plan. +*/ +static int memstatBestIndex( + sqlite3_vtab *tab, + sqlite3_index_info *pIdxInfo +){ + pIdxInfo->estimatedCost = (double)500; + pIdxInfo->estimatedRows = 500; + return SQLITE_OK; +} + +/* +** This following structure defines all the methods for the +** memstat virtual table. +*/ +static sqlite3_module memstatModule = { + 0, /* iVersion */ + 0, /* xCreate */ + memstatConnect, /* xConnect */ + memstatBestIndex, /* xBestIndex */ + memstatDisconnect, /* xDisconnect */ + 0, /* xDestroy */ + memstatOpen, /* xOpen - open a cursor */ + memstatClose, /* xClose - close a cursor */ + memstatFilter, /* xFilter - configure scan constraints */ + memstatNext, /* xNext - advance a cursor */ + memstatEof, /* xEof - check for end of scan */ + memstatColumn, /* xColumn - read data */ + memstatRowid, /* xRowid - read data */ + 0, /* xUpdate */ + 0, /* xBegin */ + 0, /* xSync */ + 0, /* xCommit */ + 0, /* xRollback */ + 0, /* xFindMethod */ + 0, /* xRename */ + 0, /* xSavepoint */ + 0, /* xRelease */ + 0, /* xRollbackTo */ + 0, /* xShadowName */ +}; + +#endif /* SQLITE_OMIT_VIRTUALTABLE */ + +int sqlite3MemstatVtabInit(sqlite3 *db){ + int rc = SQLITE_OK; +#ifndef SQLITE_OMIT_VIRTUALTABLE + rc = sqlite3_create_module(db, "sqlite_memstat", &memstatModule, 0); +#endif + return rc; +} + +#ifndef SQLITE_CORE +#ifdef _WIN32 +__declspec(dllexport) +#endif +int sqlite3_memstat_init( + sqlite3 *db, + char **pzErrMsg, + const sqlite3_api_routines *pApi +){ + int rc = SQLITE_OK; + SQLITE_EXTENSION_INIT2(pApi); +#ifndef SQLITE_OMIT_VIRTUALTABLE + rc = sqlite3MemstatVtabInit(db); +#endif + return rc; +} +#endif /* SQLITE_CORE */ +#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_MEMSTATVTAB) */ |