sql: refactor struct Schema

Refactor struct Schema - remove all unnecessary fields, save
only actually used fields like tblHash, trigHash, fkeyHash,
schema_cookie.

For #3119

src/box/sql/build.c

@@ -382,7 +382,7 @@ sqlite3ResetOneSchema(sqlite3 * db)
 {
 	/* Case 1:  Reset the single schema of the database  */
 	assert(db->pSchema != 0);
-	sqlite3SchemaClear(db->pSchema);
+	sqlite3SchemaClear(db);
 }
 
 /*
@@ -394,7 +394,7 @@ sqlite3ResetAllSchemasOfConnection(sqlite3 * db)
 {
 	struct session *user_session = current_session();
 	if (db->pSchema) {
-		sqlite3SchemaClear(db->pSchema);
+		sqlite3SchemaClear(db);
 	}
 	user_session->sql_flags &= ~SQLITE_InternChanges;
 }
@@ -1205,7 +1205,7 @@ sqlite3ChangeCookie(Parse * pParse)
 	sqlite3 *db = pParse->db;
 	Vdbe *v = pParse->pVdbe;
 	sqlite3VdbeAddOp3(v, OP_SetCookie, 0, 0,
-			  db->mdb.pSchema->schema_cookie + 1);
+			  db->pSchema->schema_cookie + 1);
 }
 
 /*
@@ -2226,7 +2226,6 @@ sqlite3ViewGetColumnNames(Parse * pParse, Table * pTable)
 	} else {
 		nErr++;
 	}
-	pTable->pSchema->schemaFlags |= DB_UnresetViews;
 #endif				/* SQLITE_OMIT_VIEW */
 	return nErr;
 }
@@ -2249,7 +2248,6 @@ sqliteViewResetAll(sqlite3 * db)
 			pTab->nCol = 0;
 		}
 	}
-	DbClearProperty(db, DB_UnresetViews);
 }
 #else
 #define sqliteViewResetAll(A,B)

src/box/sql/callback.c

@@ -387,12 +387,14 @@ sqlite3FindFunction(sqlite3 * db,	/* An open database */
  * The Schema.cache_size variable is not cleared.
  */
 void
-sqlite3SchemaClear(void *p)
+sqlite3SchemaClear(sqlite3 * db)
 {
+	assert(db->pSchema);
+
 	Hash temp1;
 	Hash temp2;
 	HashElem *pElem;
-	Schema *pSchema = (Schema *) p;
+	Schema *pSchema = db->pSchema;
 
 	temp1 = pSchema->tblHash;
 	temp2 = pSchema->trigHash;
@@ -410,11 +412,8 @@ sqlite3SchemaClear(void *p)
 	}
 	sqlite3HashClear(&temp1);
 	sqlite3HashClear(&pSchema->fkeyHash);
-	pSchema->pSeqTab = 0;
-	if (pSchema->schemaFlags & DB_SchemaLoaded) {
-		pSchema->iGeneration++;
-		pSchema->schemaFlags &= ~DB_SchemaLoaded;
-	}
+
+	db->pSchema = NULL;
 }
 
 /* Create a brand new schema. */

src/box/sql/main.c

@@ -2373,7 +2373,7 @@ openDatabase(const char *zFilename,	/* Database filename UTF-8 encoded */
 		goto opendb_out;
 	}
 
-	db->pSchema = sqlite3SchemaCreate(db);
+	db->pSchema = 0;
 	db->magic = SQLITE_MAGIC_OPEN;
 	if (db->mallocFailed) {
 		goto opendb_out;

src/box/sql/prepare.c

@@ -87,7 +87,6 @@ sqlite3InitCallback(void *pInit, int argc, char **argv, char **NotUsed)
 	assert(argc == 3);
 	UNUSED_PARAMETER2(NotUsed, argc);
 	assert(sqlite3_mutex_held(db->mutex));
-	DbClearProperty(db, DB_Empty);
 	if (db->mallocFailed) {
 		corruptSchema(pData, argv[0], 0);
 		return 1;
@@ -185,11 +184,7 @@ sqlite3InitDatabase(sqlite3 * db)
 	/* Tarantool: schema_cookie is not used so far, but
 	 * might be used in future. Set it to dummy value.
 	 */
-	pDb->pSchema->schema_cookie = 0;
-
-	if (pDb->pSchema->cache_size == 0) {
-		pDb->pSchema->cache_size = SQLITE_DEFAULT_CACHE_SIZE;
-	}
+	db->pSchema->schema_cookie = 0;
 
 	/* Read the schema information out of the schema tables
 	 */
@@ -217,9 +212,6 @@ sqlite3InitDatabase(sqlite3 * db)
 		rc = SQLITE_NOMEM_BKPT;
 		sqlite3ResetAllSchemasOfConnection(db);
 	}
-	if (rc == SQLITE_OK) {
-		DbSetProperty(db, DB_SchemaLoaded);
-	}
 
  error_out:
 	if (rc == SQLITE_NOMEM || rc == SQLITE_IOERR_NOMEM) {
@@ -231,8 +223,8 @@ sqlite3InitDatabase(sqlite3 * db)
 /*
  * Initialize all database files - the main database file
  * Return a success code.
- * After a database is initialized, the DB_SchemaLoaded
- * bit is set in the flags field of the Db structure.
+ * After a database is initialized, the pSchema field in database
+ * structure will be not NULL.
  */
 int
 sqlite3Init(sqlite3 * db)
@@ -245,7 +237,8 @@ sqlite3Init(sqlite3 * db)
 	assert(db->init.busy == 0);
 	rc = SQLITE_OK;
 	db->init.busy = 1;
-	if (!DbHasProperty(db, DB_SchemaLoaded)) {
+	if (!db->pSchema) {
+		db->pSchema = sqlite3SchemaCreate(db);
 		rc = sqlite3InitDatabase(db);
 		if (rc) {
 			sqlite3ResetOneSchema(db);

src/box/sql/sqliteInt.h

@@ -892,39 +892,12 @@ typedef int VList;
  * An instance of the following structure stores a database schema.
  */
 struct Schema {
-	int schema_cookie;	/* Database schema version number for this file */
-	int iGeneration;	/* Generation counter.  Incremented with each change */
+	int schema_cookie;      /* Database schema version number for this file */
 	Hash tblHash;		/* All tables indexed by name */
 	Hash trigHash;		/* All triggers indexed by name */
 	Hash fkeyHash;		/* All foreign keys by referenced table name */
-	Table *pSeqTab;		/* The sqlite_sequence table used by AUTOINCREMENT */
-	u8 enc;			/* Text encoding used by this database */
-	u16 schemaFlags;	/* Flags associated with this schema */
-	int cache_size;		/* Number of pages to use in the cache */
 };
 
-/*
- * These macros can be used to test, set, or clear bits in the
- * Db.pSchema->flags field.
- */
-#define DbHasProperty(D,P)     (((D)->pSchema->schemaFlags&(P))==(P))
-#define DbHasAnyProperty(D,P)  (((D)->pSchema->schemaFlags&(P))!=0)
-#define DbSetProperty(D,P)     (D)->pSchema->schemaFlags|=(P)
-
-/*
- * Allowed values for the DB.pSchema->flags field.
- *
- * The DB_SchemaLoaded flag is set after the database schema has been
- * read into internal hash tables.
- *
- * DB_UnresetViews means that one or more views have column names that
- * have been filled out.  If the schema changes, these column names might
- * changes and so the view will need to be reset.
- */
-#define DB_SchemaLoaded    0x0001	/* The schema has been loaded */
-#define DB_UnresetViews    0x0002	/* Some views have defined column names */
-#define DB_Empty           0x0004	/* The file is empty (length 0 bytes) */
-
 /*
  * The number of different kinds of things that can be limited
  * using the sqlite3_limit() interface.
@@ -3466,7 +3439,7 @@ void sqlite3DeleteIndexSamples(sqlite3 *, Index *);
 void sqlite3DefaultRowEst(Index *);
 void sqlite3RegisterLikeFunctions(sqlite3 *, int);
 int sqlite3IsLikeFunction(sqlite3 *, Expr *, int *, char *);
-void sqlite3SchemaClear(void *);
+void sqlite3SchemaClear(sqlite3 *);
 Schema *sqlite3SchemaCreate(sqlite3 *);
 int sqlite3SchemaToIndex(sqlite3 * db, Schema *);
 KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *, int, int);

src/box/sql/vdbe.c

@@ -3016,7 +3016,7 @@ case OP_AutoCommit: {
 	break;
 }
 
-/* Opcode: Transaction P1 P2 P3 P4 P5
+/* Opcode: Transaction P1 P2 * * *
  *
  * Begin a transaction on database P1 if a transaction is not already
  * active.
@@ -3039,16 +3039,6 @@ case OP_AutoCommit: {
  * entire transaction. If no error is encountered, the statement transaction
  * will automatically commit when the VDBE halts.
  *
- * If P5!=0 then this opcode also checks the schema cookie against P3
- * and the schema generation counter against P4.
- * The cookie changes its value whenever the database schema changes.
- * This operation is used to detect when that the cookie has changed
- * and that the current process needs to reread the schema.  If the schema
- * cookie in P3 differs from the schema cookie in the database header or
- * if the schema generation counter in P4 differs from the current
- * generation counter, then an SQLITE_SCHEMA error is raised and execution
- * halts.  The sqlite3_step() wrapper function might then reprepare the
- * statement and rerun it from the beginning.
  */
 case OP_Transaction: {
 	assert(p->bIsReader);
@@ -3069,7 +3059,6 @@ case OP_Transaction: {
 		}
 		goto abort_due_to_error;
 	}
-	assert(pOp->p5==0 || pOp->p4type==P4_INT32);
 
 	if (rc) goto abort_due_to_error;
 	break;
@@ -3128,7 +3117,6 @@ case OP_SetCookie: {
 	assert(p->readOnly==0);
 	/* See note about index shifting on OP_ReadCookie */
 	/* When the schema cookie changes, record the new cookie internally */
-	pDb->pSchema->schema_cookie = pOp->p3;
 	user_session->sql_flags |= SQLITE_InternChanges;
 	if (pOp->p1==1) {
 		/* Invalidate all prepared statements whenever the TEMP database
@@ -4755,7 +4743,7 @@ case OP_ParseSchema2: {
 	char *argv[4] = {NULL, NULL, NULL, NULL};
 
 
-	assert(DbHasProperty(db, DB_SchemaLoaded));
+	assert(db->pSchema);
 
 	initData.db = db;
 	initData.pzErrMsg = &p->zErrMsg;
@@ -4809,7 +4797,7 @@ case OP_ParseSchema3: {
 	Mem *pRec;
 	char zPgnoBuf[16];
 	char *argv[4] = {NULL, zPgnoBuf, NULL, NULL};
-	assert(DbHasProperty(db, DB_SchemaLoaded));
+	assert(db->pSchema);
 
 	initData.db = db;
 	initData.pzErrMsg = &p->zErrMsg;

src/box/sql/vdbesort.c

@@ -913,15 +913,8 @@ sqlite3VdbeSorterInit(sqlite3 * db,	/* Database connection (for malloc()) */
 			u32 szPma = sqlite3GlobalConfig.szPma;
 			pSorter->mnPmaSize = szPma * pgsz;
 
-			mxCache = db->mdb.pSchema->cache_size;
-			if (mxCache < 0) {
-				/* A negative cache-size value C indicates that the cache is abs(C)
-				 * KiB in size.
-				 */
-				mxCache = mxCache * -1024;
-			} else {
-				mxCache = mxCache * pgsz;
-			}
+			mxCache = SQLITE_DEFAULT_CACHE_SIZE;
+			mxCache = mxCache * -1024;
 			mxCache = MIN(mxCache, SQLITE_MAX_PMASZ);
 			pSorter->mxPmaSize =
 			    MAX(pSorter->mnPmaSize, (int)mxCache);