seems memory leak happens when using cgo

[AaronLin98]

version: gorocksdb@v1.6.36

function: write_batch.go

func (wb *WriteBatch) Put(key, value []byte) {
	cKey := byteToChar(key)
	cValue := byteToChar(value)
	C.rocksdb_writebatch_put(wb.c, cKey, C.size_t(len(key)), cValue, C.size_t(len(value)))
}

use case:

func writeLargeObjects(db *grocksdb.DB) {
	for i := 0; i < 1000; i += 10 {
		writeLargeObjectsCore(db, i, i+10)
	}
}
func writeLargeObjectsCore(db *grocksdb.DB, l, r int) {
	largeValue := make([]byte, 1*1024*1024) // 1MB bytes
	for i := range largeValue {
		largeValue[i] = 'x'
	}

	batch := grocksdb.NewWriteBatch()
	for i := l; i < r; i++ {
		key := fmt.Sprintf("large_key_%d", i)
		batch.Put([]byte(key), largeValue)
	}

	writeOpts := grocksdb.NewDefaultWriteOptions()
	err := db.Write(writeOpts, batch)
	if err != nil {
		log.Fatalf("Write failed: %v", err)
	}
	writeOpts.Destroy()
	batch.Destroy()
}

results:
By this use case, memory leak will happen.
The VmRSS is much larger than Go sys memory and rocksdb-memtable and rocksdb-block-cache.

[linxGnu]

@AaronLin98

v1.6.36 is outdated. I highly recommend upgrading both RocksDB & grocksdb to newer version and give it another try.

[AaronLin98]

I have tried the new version, it seems like cgo has some problem for memory leak

[linxGnu]

@AaronLin98

Sorry for late reply due to personal matter. Have you tried:

• Upgrade to latest version
• Calling writebatch.Clear() before writebatch.Destroy()