Add transaction conditional for reseting and tracking last position i…

…n freelist

dependencies/lmdb/libraries/liblmdb/mdb.c

@@ -2728,7 +2728,7 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
 	}
 	unsigned empty_entries = 0;
 	unsigned cache_size = env->me_block_size_cache[0];
-	pgno_t best_fit_start; // this is a block we will use if we don't find an exact fit
+	unsigned best_fit_start; // this is a block we will use if we don't find an exact fit
 	pgno_t best_fit_size;
 	for (op = MDB_FIRST;; op = MDB_NEXT) {
 		MDB_val key, data;
@@ -2758,8 +2758,9 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
 		unsigned block_size = 0;
 		ssize_t entry;
 		empty_entries = 0;
+		mdb_midl_print(stderr, mop);
 		// TODO: Skip this on the first iteration, since we already checked the cache
-		for (i = 1; i <= mop_len; i++) {
+		for (i = env->me_freelist_position || 1; i <= mop_len; i++) {
 			entry = mop[i];
 			//fprintf(stderr, "pgno %u next would be %u\n", entry, block_start + block_size);
 			if (entry == 0) {
@@ -2783,6 +2784,12 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
 				} else if (block_size < best_fit_size || best_fit_size == 0) {
 					best_fit_start = i - 1;
 					best_fit_size = block_size;
+					if (i == env->me_freelist_position) {
+						// TODO: Only if we are in the same transaction
+						// if we just wrote to this block and we are continuing on this block,
+						// skip ahead to using this block
+						goto continue_best_fit;
+					}
 				}
 			}
 			if (block_size > 0) {
@@ -2802,6 +2809,7 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
 			//if (mop[i-n2] == pgno+n2)
 			//	goto search_done;
 		}
+		env->me_freelist_position = 1;
 		i = 0;
 
 		if (op == MDB_FIRST) {	/* 1st iteration */
@@ -2889,12 +2897,13 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
 		if (mop != env->me_pghead) env->me_pghead = mop;
 		mop_len = mop[0];
 	}
+	continue_best_fit:
 	if (best_fit_start > 0) {
 		mop[best_fit_start] += num; // block length is a negative, so we add to it in order to subtract the amount we are using
 		if (mop[best_fit_start] == -1) mop[best_fit_start] = 0;
 		pgno = mop[best_fit_start + 1];
 		mop[best_fit_start + 1] += num;
-		env->me_freelist_position = pgno;
+		env->me_freelist_position = best_fit_start;
 		fprintf(stderr, "using best fit at %u size %u of %u\n", pgno, num, best_fit_size);
 		env->me_block_size_cache[best_fit_size] = 0; // clear this out of the cache (TODO: could move it)
 
@@ -3484,6 +3493,15 @@ mdb_txn_renew0(MDB_txn *txn)
 		if (ti) {
 			if (LOCK_MUTEX(rc, env, env->me_wmutex))
 				return rc;
+			// TODO: This should really be equality check and mt_txnid should be decremented if nothing was written
+			if (txn->mt_txnid < ti->mti_txnid) {
+				if (env->me_pghead) mdb_midl_free(env->me_pghead);
+				env->me_pghead = NULL;
+				env->me_pglast = 0;
+				env->me_freelist_position = 0;
+				// TODO: Free it first
+				env->me_block_size_cache = NULL;
+			}
 			txn->mt_txnid = ti->mti_txnid;
 			meta = env->me_metas[txn->mt_txnid & 1];
 		} else {

dependencies/lmdb/libraries/liblmdb/midl.c

@@ -106,22 +106,54 @@ int mdb_midl_insert( MDB_IDL* ids_ref, MDB_ID id )
 	} else {
 		if (x > ids[0]) return -3; // at the end
 		ssize_t next_id = ids[x];
-		if (next_id < 0) next_id = ids[x + 1];
-		if (id - 1 == next_id && next_id > 0) {
-			// connected to next entry
-			ids[x]--; // increment negatively, as we have just expanded a block
-			// ids[x + 1] = id; // no need to adjust id, so since we are adding to the end of the block
-			return 0;
+		unsigned next_count = 1;
+		if (next_id < 0) {
+			next_count = -next_id;
+			next_id = ids[x + 1];
 		}
 		unsigned before = x; // this will end up pointing to an entry or zero right before a block of empty space
 		while (!ids[--before] && before > 0) {
 			// move past empty entries
 		}
+		if (id - next_count == next_id && next_id > 0) {
+			// connected to next entry
+			ssize_t count = next_count + 1;
+			// ids[x + 1] = id; // no need to adjust id, so since we are adding to the end of the block
+
+			if (before > 0) {
+				MDB_ID previous_id = before > 0 ? ids[before] : 0;
+				int previous_count = before > 1 ? -ids[before - 1] : 0;
+				if (previous_count < 1) previous_count = 1;
+				if (previous_id - 1 == id) {
+					// the block we just added to can now be connected to previous entry
+					count += previous_count;
+					if (previous_count > 1) {
+						ids[before - 1] = 0; // remove previous length
+					}
+					ids[before] = 0; // remove previous id
+					if (next_count == 1) {
+						// we can safely add the new count to the empty space
+						ids[x - 1] = -count; // update the count
+						return 0;
+					}
+				}
+			}
+			if (next_count > 1) {
+				ids[x] = -count; // update the count
+			} else if (ids[x - 1] == 0) {
+				ids[x - 1] = -2;
+			} else {
+				id = -2; // switching a single entry to a block size of 2
+				x--;
+				goto insert_id;
+			}
+			return 0;
+		}
 		if (before > 0) {
-			MDB_ID next_id = before > 0 ? ids[before] : 0;
+			MDB_ID previous_id = before > 0 ? ids[before] : 0;
 			int count = before > 1 ? -ids[before - 1] : 0;
 			if (count < 1) count = 1;
-			if (next_id - 1 == id) {
+			if (previous_id - 1 == id) {
 				// connected to previous entry
 				ids[before]--; // adjust the starting block to include this
 				if (count > 1) {
@@ -213,6 +245,7 @@ int mdb_midl_need( MDB_IDL *idp, unsigned num )
 		MDB_IDL new_ids; 
 		if (!(new_ids = calloc(num, sizeof(MDB_ID))))
 			return ENOMEM;
+		fprintf(stderr, "Created new id list of size %u\n", num);
 		*new_ids++ = num - 2;
 		*new_ids = num - 2;
 		unsigned j = 1;
@@ -226,6 +259,7 @@ int mdb_midl_need( MDB_IDL *idp, unsigned num )
 			new_ids[j++] = entry;
 			if (entry < 0) new_ids[j++] = ids[++i]; // this was a block with a length
 		}
+		mdb_midl_free(ids);
 		// now shrink (or grow) back to appropriate size
 		num = (j + (j >> 3) + 22) & -16;
 		if (num > new_ids[0]) num = new_ids[0];
@@ -237,6 +271,28 @@ int mdb_midl_need( MDB_IDL *idp, unsigned num )
 	return 0;
 }
 
+int mdb_midl_print( FILE *fp, MDB_IDL ids )
+{
+	if (ids == NULL) {
+		fprintf(fp, "freelist: NULL\n");
+		return 0;
+	}
+	unsigned i;
+	fprintf(fp, "freelist: %u: ", ids[0]);
+	for (i=1; i<=ids[0]; i++) {
+		ssize_t entry = ids[i];
+		if (entry < 0) {
+			fprintf(fp, "%li-%li ", ids[i+1], ids[i+1] - entry - 1);
+			i++;
+		} else if (ids[i] == 0) {
+			fprintf(fp, "_");
+		} else {
+			fprintf(fp, "%lu ", (unsigned long)ids[i]);
+		}
+	}
+	fprintf(fp, "\n");
+	return 0;
+}
 int mdb_midl_append( MDB_IDL *idp, MDB_ID id )
 {
 	MDB_IDL ids = *idp;

dependencies/lmdb/libraries/liblmdb/midl.h

@@ -28,6 +28,8 @@
 #define _MDB_MIDL_H_
 
 #include "lmdb.h"
+#include <stdio.h>
+
 
 #ifdef __cplusplus
 extern "C" {
@@ -109,6 +111,7 @@ void mdb_midl_shrink(MDB_IDL *idp);
 	 */
 int mdb_midl_need(MDB_IDL *idp, unsigned num);
 
+int mdb_midl_print( FILE *fp, MDB_IDL ids );
 /** Insert an ID into an IDL.
  * @param[in,out] idp	Address of the IDL to append to.
  * @param[in] id	The ID to append.