diff options
Diffstat (limited to 'ndb/include/ndbapi/NdbBlob.hpp')
| -rw-r--r-- | ndb/include/ndbapi/NdbBlob.hpp | 86 |
1 files changed, 66 insertions, 20 deletions
diff --git a/ndb/include/ndbapi/NdbBlob.hpp b/ndb/include/ndbapi/NdbBlob.hpp index 9398f77c474..dc47115d16f 100644 --- a/ndb/include/ndbapi/NdbBlob.hpp +++ b/ndb/include/ndbapi/NdbBlob.hpp @@ -50,24 +50,33 @@ class NdbColumnImpl; * - closed: after transaction commit * - invalid: after rollback or transaction close * - * NdbBlob supports 2 styles of data access: + * NdbBlob supports 3 styles of data access: * * - in prepare phase, NdbBlob methods getValue and setValue are used to - * prepare a read or write of a single blob value of known size + * prepare a read or write of a blob value of known size * - * - in active phase, NdbBlob methods readData and writeData are used to - * read or write blob data of undetermined size + * - in prepare phase, setActiveHook is used to define a routine which + * is invoked as soon as the handle becomes active + * + * - in active phase, readData and writeData are used to read or write + * blob data of arbitrary size + * + * The styles can be applied in combination (in above order). + * + * Blob operations take effect at next transaction execute. In some + * cases NdbBlob is forced to do implicit executes. To avoid this, + * operate on complete blob parts. + * + * Use NdbConnection::executePendingBlobOps to flush your reads and + * writes. It avoids execute penalty if nothing is pending. It is not + * needed after execute (obviously) or after next scan result. * * NdbBlob methods return -1 on error and 0 on success, and use output * parameters when necessary. * * Notes: * - table and its blob part tables are not created atomically - * - blob data operations take effect at next transaction execute - * - NdbBlob may need to do implicit executes on the transaction - * - read and write of complete parts is much more efficient * - scan must use the "new" interface NdbScanOperation - * - scan with blobs applies hold-read-lock (at minimum) * - to update a blob in a read op requires exclusive tuple lock * - update op in scan must do its own getBlobHandle * - delete creates implicit, not-accessible blob handles @@ -78,12 +87,16 @@ class NdbColumnImpl; * - scan must use exclusive locking for now * * Todo: - * - add scan method hold-read-lock-until-next + return-keyinfo - * - better check of keyinfo length when setting keys - * - better check of allowed blob op vs locking mode + * - add scan method hold-read-lock + return-keyinfo + * - check keyinfo length when setting keys + * - check allowed blob ops vs locking mode + * - overload control (too many pending ops) */ class NdbBlob { public: + /** + * State. + */ enum State { Idle = 0, Prepared = 1, @@ -93,8 +106,14 @@ public: }; State getState(); /** + * Inline blob header. + */ + struct Head { + Uint64 length; + }; + /** * Prepare to read blob value. The value is available after execute. - * Use isNull to check for NULL and getLength to get the real length + * Use getNull to check for NULL and getLength to get the real length * and to check for truncation. Sets current read/write position to * after the data read. */ @@ -107,6 +126,20 @@ public: */ int setValue(const void* data, Uint32 bytes); /** + * Callback for setActiveHook. Invoked immediately when the prepared + * operation has been executed (but not committed). Any getValue or + * setValue is done first. The blob handle is active so readData or + * writeData etc can be used to manipulate blob value. A user-defined + * argument is passed along. Returns non-zero on error. + */ + typedef int ActiveHook(NdbBlob* me, void* arg); + /** + * Define callback for blob handle activation. The queue of prepared + * operations will be executed in no commit mode up to this point and + * then the callback is invoked. + */ + int setActiveHook(ActiveHook* activeHook, void* arg); + /** * Check if blob is null. */ int getNull(bool& isNull); @@ -115,7 +148,7 @@ public: */ int setNull(); /** - * Get current length in bytes. Use isNull to distinguish between + * Get current length in bytes. Use getNull to distinguish between * length 0 blob and NULL blob. */ int getLength(Uint64& length); @@ -180,6 +213,13 @@ public: static const int ErrAbort = 4268; // "Unknown blob error" static const int ErrUnknown = 4269; + /** + * Return info about all blobs in this operation. + */ + // Get first blob in list + NdbBlob* blobsFirstBlob(); + // Get next blob in list after this one + NdbBlob* blobsNextBlob(); private: friend class Ndb; @@ -187,20 +227,20 @@ private: friend class NdbOperation; friend class NdbScanOperation; friend class NdbDictionaryImpl; + friend class NdbResultSet; // atNextResult // state State theState; void setState(State newState); // define blob table static void getBlobTableName(char* btname, const NdbTableImpl* t, const NdbColumnImpl* c); static void getBlobTable(NdbTableImpl& bt, const NdbTableImpl* t, const NdbColumnImpl* c); - // table name - char theBlobTableName[BlobTableNameSize]; // ndb api stuff Ndb* theNdb; NdbConnection* theNdbCon; NdbOperation* theNdbOp; NdbTableImpl* theTable; NdbTableImpl* theAccessTable; + NdbTableImpl* theBlobTable; const NdbColumnImpl* theColumn; char theFillChar; // sizes @@ -213,10 +253,11 @@ private: bool theSetFlag; const char* theSetBuf; Uint32 theGetSetBytes; - // head - struct Head { - Uint64 length; - }; + // pending ops + Uint8 thePendingBlobOps; + // activation callback + ActiveHook* theActiveHook; + void* theActiveHookArg; // buffers struct Buf { char* data; @@ -234,7 +275,6 @@ private: char* theInlineData; NdbRecAttr* theHeadInlineRecAttr; bool theHeadInlineUpdateFlag; - bool theNewPartFlag; // length and read/write position int theNullFlag; Uint64 theLength; @@ -275,6 +315,11 @@ private: int insertParts(const char* buf, Uint32 part, Uint32 count); int updateParts(const char* buf, Uint32 part, Uint32 count); int deleteParts(Uint32 part, Uint32 count); + // pending ops + int executePendingBlobReads(); + int executePendingBlobWrites(); + // callbacks + int invokeActiveHook(); // blob handle maintenance int atPrepare(NdbConnection* aCon, NdbOperation* anOp, const NdbColumnImpl* aColumn); int preExecute(ExecType anExecType, bool& batch); @@ -286,6 +331,7 @@ private: void setErrorCode(NdbOperation* anOp, bool invalidFlag = true); void setErrorCode(NdbConnection* aCon, bool invalidFlag = true); #ifdef VM_TRACE + int getOperationType() const; friend class NdbOut& operator<<(NdbOut&, const NdbBlob&); #endif }; |