dylanlott/tree-store-diff.txt

## tree-store-diff.txt
`git diff main:persistence/state.go persistence/tree-store:persistence/trees/trees.go > tree-store-diff.txt`

---

diff --git a/persistence/state.go b/persistence/trees/trees.go
index e8252d6f..cd0d2302 100644
--- a/persistence/state.go
+++ b/persistence/trees/trees.go
@@ -1,29 +1,64 @@
-package persistence
+// package trees maintains a set of sparse merkle trees
+// each backed by the KVStore interface. It offers an atomic
+// commit and rollback mechanism for interacting with
+// that core resource map of merkle trees.
+package trees

 import (
 	"bytes"
+	"context"
 	"crypto/sha256"
 	"encoding/hex"
 	"fmt"

+	"github.com/jackc/pgx/v5"
+
+	"github.com/pokt-network/pocket/persistence/indexer"
 	"github.com/pokt-network/pocket/persistence/kvstore"
-	"github.com/pokt-network/pocket/persistence/types"
+	ptypes "github.com/pokt-network/pocket/persistence/types"
 	"github.com/pokt-network/pocket/shared/codec"
 	coreTypes "github.com/pokt-network/pocket/shared/core/types"
 	"github.com/pokt-network/pocket/shared/crypto"
 	"github.com/pokt-network/smt"
 )

-type merkleTree float64
+var merkleTreeToString = map[merkleTree]string{
+	appMerkleTree:      "app",
+	valMerkleTree:      "val",
+	fishMerkleTree:     "fish",
+	servicerMerkleTree: "servicer",

-type stateTrees struct {
-	merkleTrees map[merkleTree]*smt.SMT
+	accountMerkleTree: "account",
+	poolMerkleTree:    "pool",

-	// nodeStores are part of the SMT, but references are kept below for convenience
-	// and debugging purposes
-	nodeStores map[merkleTree]kvstore.KVStore
+	transactionsMerkleTree: "transactions",
+	paramsMerkleTree:       "params",
+	flagsMerkleTree:        "flags",
 }

+var actorTypeToMerkleTreeName = map[coreTypes.ActorType]merkleTree{
+	coreTypes.ActorType_ACTOR_TYPE_APP:      appMerkleTree,
+	coreTypes.ActorType_ACTOR_TYPE_VAL:      valMerkleTree,
+	coreTypes.ActorType_ACTOR_TYPE_FISH:     fishMerkleTree,
+	coreTypes.ActorType_ACTOR_TYPE_SERVICER: servicerMerkleTree,
+}
+
+var actorTypeToSchemaName = map[coreTypes.ActorType]ptypes.ProtocolActorSchema{
+	coreTypes.ActorType_ACTOR_TYPE_APP:      ptypes.ApplicationActor,
+	coreTypes.ActorType_ACTOR_TYPE_VAL:      ptypes.ValidatorActor,
+	coreTypes.ActorType_ACTOR_TYPE_FISH:     ptypes.FishermanActor,
+	coreTypes.ActorType_ACTOR_TYPE_SERVICER: ptypes.ServicerActor,
+}
+
+var merkleTreeToActorTypeName = map[merkleTree]coreTypes.ActorType{
+	appMerkleTree:      coreTypes.ActorType_ACTOR_TYPE_APP,
+	valMerkleTree:      coreTypes.ActorType_ACTOR_TYPE_VAL,
+	fishMerkleTree:     coreTypes.ActorType_ACTOR_TYPE_FISH,
+	servicerMerkleTree: coreTypes.ActorType_ACTOR_TYPE_SERVICER,
+}
+
+type merkleTree float64
+
 // A list of Merkle Trees used to maintain the state hash.
 const (
 	// IMPORTANT: The order in which these trees are defined is important and strict. It implicitly
@@ -49,49 +84,32 @@ const (
 	numMerkleTrees
 )

-var merkleTreeToString = map[merkleTree]string{
-	appMerkleTree:      "app",
-	valMerkleTree:      "val",
-	fishMerkleTree:     "fish",
-	servicerMerkleTree: "servicer",
-
-	accountMerkleTree: "account",
-	poolMerkleTree:    "pool",
-
-	transactionsMerkleTree: "transactions",
-	paramsMerkleTree:       "params",
-	flagsMerkleTree:        "flags",
-}
-
-var actorTypeToMerkleTreeName = map[coreTypes.ActorType]merkleTree{
-	coreTypes.ActorType_ACTOR_TYPE_APP:      appMerkleTree,
-	coreTypes.ActorType_ACTOR_TYPE_VAL:      valMerkleTree,
-	coreTypes.ActorType_ACTOR_TYPE_FISH:     fishMerkleTree,
-	coreTypes.ActorType_ACTOR_TYPE_SERVICER: servicerMerkleTree,
-}
-
-var actorTypeToSchemaName = map[coreTypes.ActorType]types.ProtocolActorSchema{
-	coreTypes.ActorType_ACTOR_TYPE_APP:      types.ApplicationActor,
-	coreTypes.ActorType_ACTOR_TYPE_VAL:      types.ValidatorActor,
-	coreTypes.ActorType_ACTOR_TYPE_FISH:     types.FishermanActor,
-	coreTypes.ActorType_ACTOR_TYPE_SERVICER: types.ServicerActor,
+// treeStore stores a set of merkle trees that
+// it manages. It fulfills the modules.TreeStore interface.
+// * It is responsible for commit or rollback behavior
+// of the underlying trees by utilizing the lazy loading
+// functionality provided by the underlying smt library.
+type treeStore struct {
+	treeStoreDir string
+	merkleTrees  map[merkleTree]*smt.SMT
+	nodeStores   map[merkleTree]kvstore.KVStore
 }

-var merkleTreeToActorTypeName = map[merkleTree]coreTypes.ActorType{
-	appMerkleTree:      coreTypes.ActorType_ACTOR_TYPE_APP,
-	valMerkleTree:      coreTypes.ActorType_ACTOR_TYPE_VAL,
-	fishMerkleTree:     coreTypes.ActorType_ACTOR_TYPE_FISH,
-	servicerMerkleTree: coreTypes.ActorType_ACTOR_TYPE_SERVICER,
+// Update takes a transaction and a height and updates
+// all of the trees in the treeStore for that height.
+func (t *treeStore) Update(pgtx pgx.Tx, txi indexer.TxIndexer, height uint64) (string, error) {
+	return t.updateMerkleTrees(pgtx, txi, height)
 }

-func newStateTrees(treesStoreDir string) (*stateTrees, error) {
-	if treesStoreDir == "" {
+func NewStateTrees(treesStoreDir string) (*treeStore, error) {
+	if treesStoreDir == ":memory:" {
 		return newMemStateTrees()
 	}

-	stateTrees := &stateTrees{
-		merkleTrees: make(map[merkleTree]*smt.SMT, int(numMerkleTrees)),
-		nodeStores:  make(map[merkleTree]kvstore.KVStore, int(numMerkleTrees)),
+	stateTrees := &treeStore{
+		treeStoreDir: treesStoreDir,
+		merkleTrees:  make(map[merkleTree]*smt.SMT, int(numMerkleTrees)),
+		nodeStores:   make(map[merkleTree]kvstore.KVStore, int(numMerkleTrees)),
 	}

 	for tree := merkleTree(0); tree < numMerkleTrees; tree++ {
@@ -105,8 +123,23 @@ func newStateTrees(treesStoreDir string) (*stateTrees, error) {
 	return stateTrees, nil
 }

-func newMemStateTrees() (*stateTrees, error) {
-	stateTrees := &stateTrees{
+// DebugClearAll is used by the debug cli to completely reset all merkle trees.
+// This should only be called by the debug CLI.
+func (t *treeStore) DebugClearAll() error {
+	for treeType := merkleTree(0); treeType < numMerkleTrees; treeType++ {
+		nodeStore := t.nodeStores[treeType]
+		if err := nodeStore.ClearAll(); err != nil {
+			return fmt.Errorf("failed to clear %s node store: %w", merkleTreeToString[treeType], err)
+		}
+		t.merkleTrees[treeType] = smt.NewSparseMerkleTree(nodeStore, sha256.New())
+	}
+
+	return nil
+}
+
+// newMemStateTrees creates a new in-memory state tree
+func newMemStateTrees() (*treeStore, error) {
+	stateTrees := &treeStore{
 		merkleTrees: make(map[merkleTree]*smt.SMT, int(numMerkleTrees)),
 		nodeStores:  make(map[merkleTree]kvstore.KVStore, int(numMerkleTrees)),
 	}
@@ -118,8 +151,9 @@ func newMemStateTrees() (*stateTrees, error) {
 	return stateTrees, nil
 }

-func (p *PostgresContext) updateMerkleTrees() (string, error) {
-	// Update all the merkle trees
+// updateMerkleTrees updates all of the merkle trees that TreeStore manages.
+// * it returns an hash of the output or an error.
+func (t *treeStore) updateMerkleTrees(pgtx pgx.Tx, txi indexer.TxIndexer, height uint64) (string, error) {
 	for treeType := merkleTree(0); treeType < numMerkleTrees; treeType++ {
 		switch treeType {
 		// Actor Merkle Trees
@@ -128,66 +162,102 @@ func (p *PostgresContext) updateMerkleTrees() (string, error) {
 			if !ok {
 				return "", fmt.Errorf("no actor type found for merkle tree: %v", treeType)
 			}
-			if err := p.updateActorsTree(actorType); err != nil {
+
+			actors, err := t.getActorsUpdated(pgtx, actorType, height)
+			if err != nil {
+				return "", fmt.Errorf("failed to get actors at height: %w", err)
+			}
+
+			if err := t.updateActorsTree(actorType, actors); err != nil {
 				return "", fmt.Errorf("failed to update actors tree for treeType: %v, actorType: %v - %w", treeType, actorType, err)
 			}

 		// Account Merkle Trees
 		case accountMerkleTree:
-			if err := p.updateAccountTrees(); err != nil {
-				return "", fmt.Errorf("failed to update account trees - %w", err)
+			accounts, err := t.getAccounts(pgtx, height)
+			if err != nil {
+				return "", fmt.Errorf("failed to get accounts: %w", err)
+			}
+			if err := t.updateAccountTrees(accounts); err != nil {
+				return "", fmt.Errorf("failed to update account trees: %w", err)
 			}
 		case poolMerkleTree:
-			if err := p.updatePoolTrees(); err != nil {
+			pools, err := t.getPools(pgtx, height)
+			if err != nil {
+				return "", fmt.Errorf("failed to get transactions: %w", err)
+			}
+			if err := t.updatePoolTrees(pools); err != nil {
 				return "", fmt.Errorf("failed to update pool trees - %w", err)
 			}

 		// Data Merkle Trees
 		case transactionsMerkleTree:
-			if err := p.updateTransactionsTree(); err != nil {
-				return "", fmt.Errorf("failed to update transactions tree - %w", err)
+			indexedTxs, err := t.getTransactions(txi, height)
+			if err != nil {
+				return "", fmt.Errorf("failed to get transactions: %w", err)
+			}
+			if err := t.updateTransactionsTree(indexedTxs); err != nil {
+				return "", fmt.Errorf("failed to update transactions: %w", err)
 			}
 		case paramsMerkleTree:
-			if err := p.updateParamsTree(); err != nil {
-				return "", fmt.Errorf("failed to update params tree - %w", err)
+			params, err := t.getParams(pgtx, height)
+			if err != nil {
+				return "", fmt.Errorf("failed to get params: %w", err)
+			}
+			if err := t.updateParamsTree(params); err != nil {
+				return "", fmt.Errorf("failed to update params tree: %w", err)
 			}
 		case flagsMerkleTree:
-			if err := p.updateFlagsTree(); err != nil {
+			flags, err := t.getFlags(pgtx, height)
+			if err != nil {
+				return "", fmt.Errorf("failed to get flags from transaction: %w", err)
+			}
+			if err := t.updateFlagsTree(flags); err != nil {
 				return "", fmt.Errorf("failed to update flags tree - %w", err)
 			}
-
 		// Default
 		default:
-			p.logger.Fatal().Msgf("Not handled yet in state commitment update. Merkle tree #{%v}", treeType)
+			panic(fmt.Sprintf("not handled in state commitment update. Merkle tree #{%v}", treeType))
 		}
 	}

-	return p.getStateHash(), nil
+	if err := t.commit(); err != nil {
+		return "", fmt.Errorf("failed to commit: %w", err)
+	}
+	return t.getStateHash(), nil
 }

-func (p *PostgresContext) getStateHash() string {
-	// Get the root of each Merkle Tree
+func (t *treeStore) commit() error {
+	for tree := merkleTree(0); tree < numMerkleTrees; tree++ {
+		if err := t.merkleTrees[tree].Commit(); err != nil {
+			return fmt.Errorf("failed to commit %s: %w", merkleTreeToString[tree], err)
+		}
+	}
+	return nil
+}
+
+func (t *treeStore) getStateHash() string {
+	// create an order-matters list of roots
 	roots := make([][]byte, 0)
 	for tree := merkleTree(0); tree < numMerkleTrees; tree++ {
-		roots = append(roots, p.stateTrees.merkleTrees[tree].Root())
+		roots = append(roots, t.merkleTrees[tree].Root())
 	}

-	// Get the state hash
+	// combine them and hash the result
 	rootsConcat := bytes.Join(roots, []byte{})
 	stateHash := sha256.Sum256(rootsConcat)

 	// Convert the array to a slice and return it
+	// REF: https://stackoverflow.com/questions/28886616/convert-array-to-slice-in-go
 	return hex.EncodeToString(stateHash[:])
 }

-// Actor Tree Helpers
-
-func (p *PostgresContext) updateActorsTree(actorType coreTypes.ActorType) error {
-	actors, err := p.getActorsUpdatedAtHeight(actorType, p.Height)
-	if err != nil {
-		return err
-	}
+////////////////////////
+// Actor Tree Helpers //
+////////////////////////

+// NB: I think this needs to be done manually for all 4 types.
+func (t *treeStore) updateActorsTree(actorType coreTypes.ActorType, actors []*coreTypes.Actor) error {
 	for _, actor := range actors {
 		bzAddr, err := hex.DecodeString(actor.GetAddress())
 		if err != nil {
@@ -203,12 +273,7 @@ func (p *PostgresContext) updateActorsTree(actorType coreTypes.ActorType) error
 		if !ok {
 			return fmt.Errorf("no merkle tree found for actor type: %s", actorType)
 		}
-		if err := p.stateTrees.merkleTrees[merkleTreeName].Update(bzAddr, actorBz); err != nil {
-			return err
-		}
-
-		// If no errors updating then commit changes to the nodestore
-		if err := p.stateTrees.merkleTrees[merkleTreeName].Commit(); err != nil {
+		if err := t.merkleTrees[merkleTreeName].Update(bzAddr, actorBz); err != nil {
 			return err
 		}
 	}
@@ -216,43 +281,11 @@ func (p *PostgresContext) updateActorsTree(actorType coreTypes.ActorType) error
 	return nil
 }

-func (p *PostgresContext) getActorsUpdatedAtHeight(actorType coreTypes.ActorType, height int64) (actors []*coreTypes.Actor, err error) {
-	actorSchema, ok := actorTypeToSchemaName[actorType]
-	if !ok {
-		return nil, fmt.Errorf("no schema found for actor type: %s", actorType)
-	}
-
-	schemaActors, err := p.GetActorsUpdated(actorSchema, height)
-	if err != nil {
-		return nil, err
-	}
-
-	actors = make([]*coreTypes.Actor, len(schemaActors))
-	for i, schemaActor := range schemaActors {
-		actor := &coreTypes.Actor{
-			ActorType:       actorType,
-			Address:         schemaActor.Address,
-			PublicKey:       schemaActor.PublicKey,
-			Chains:          schemaActor.Chains,
-			ServiceUrl:      schemaActor.ServiceUrl,
-			StakedAmount:    schemaActor.StakedAmount,
-			PausedHeight:    schemaActor.PausedHeight,
-			UnstakingHeight: schemaActor.UnstakingHeight,
-			Output:          schemaActor.Output,
-		}
-		actors[i] = actor
-	}
-	return
-}
-
-// Account Tree Helpers
-
-func (p *PostgresContext) updateAccountTrees() error {
-	accounts, err := p.GetAccountsUpdated(p.Height)
-	if err != nil {
-		return err
-	}
+//////////////////////////
+// Account Tree Helpers //
+//////////////////////////

+func (t *treeStore) updateAccountTrees(accounts []*coreTypes.Account) error {
 	for _, account := range accounts {
 		bzAddr, err := hex.DecodeString(account.GetAddress())
 		if err != nil {
@@ -264,12 +297,7 @@ func (p *PostgresContext) updateAccountTrees() error {
 			return err
 		}

-		if err := p.stateTrees.merkleTrees[accountMerkleTree].Update(bzAddr, accBz); err != nil {
-			return err
-		}
-
-		// If no errors updating then commit changes to the nodestore
-		if err := p.stateTrees.merkleTrees[accountMerkleTree].Commit(); err != nil {
+		if err := t.merkleTrees[accountMerkleTree].Update(bzAddr, accBz); err != nil {
 			return err
 		}
 	}
@@ -277,12 +305,7 @@ func (p *PostgresContext) updateAccountTrees() error {
 	return nil
 }

-func (p *PostgresContext) updatePoolTrees() error {
-	pools, err := p.GetPoolsUpdated(p.Height)
-	if err != nil {
-		return err
-	}
-
+func (t *treeStore) updatePoolTrees(pools []*coreTypes.Account) error {
 	for _, pool := range pools {
 		bzAddr, err := hex.DecodeString(pool.GetAddress())
 		if err != nil {
@@ -294,12 +317,7 @@ func (p *PostgresContext) updatePoolTrees() error {
 			return err
 		}

-		if err := p.stateTrees.merkleTrees[poolMerkleTree].Update(bzAddr, accBz); err != nil {
-			return err
-		}
-
-		// If no errors updating then commit changes to the nodestore
-		if err := p.stateTrees.merkleTrees[poolMerkleTree].Commit(); err != nil {
+		if err := t.merkleTrees[poolMerkleTree].Update(bzAddr, accBz); err != nil {
 			return err
 		}
 	}
@@ -307,48 +325,44 @@ func (p *PostgresContext) updatePoolTrees() error {
 	return nil
 }

-// Data Tree Helpers
-
-func (p *PostgresContext) updateTransactionsTree() error {
-	indexedTxs, err := p.txIndexer.GetByHeight(p.Height, false)
-	if err != nil {
-		return err
-	}
+///////////////////////
+// Data Tree Helpers //
+///////////////////////

+func (t *treeStore) updateTransactionsTree(indexedTxs []*coreTypes.IndexedTransaction) error {
 	for _, idxTx := range indexedTxs {
 		txBz := idxTx.GetTx()
 		txHash := crypto.SHA3Hash(txBz)
-		if err := p.stateTrees.merkleTrees[transactionsMerkleTree].Update(txHash, txBz); err != nil {
-			return err
-		}
-
-		// If no errors updating then commit changes to the nodestore
-		if err := p.stateTrees.merkleTrees[transactionsMerkleTree].Commit(); err != nil {
+		if err := t.merkleTrees[transactionsMerkleTree].Update(txHash, txBz); err != nil {
 			return err
 		}
 	}
-
 	return nil
 }

-func (p *PostgresContext) updateParamsTree() error {
-	params, err := p.getParamsUpdated(p.Height)
-	if err != nil {
-		return err
-	}
-
+func (t *treeStore) updateParamsTree(params []*coreTypes.Param) error {
 	for _, param := range params {
 		paramBz, err := codec.GetCodec().Marshal(param)
 		paramKey := crypto.SHA3Hash([]byte(param.Name))
 		if err != nil {
 			return err
 		}
-		if err := p.stateTrees.merkleTrees[paramsMerkleTree].Update(paramKey, paramBz); err != nil {
+		if err := t.merkleTrees[paramsMerkleTree].Update(paramKey, paramBz); err != nil {
 			return err
 		}
+	}

-		// If no errors updating then commit changes to the nodestore
-		if err := p.stateTrees.merkleTrees[paramsMerkleTree].Commit(); err != nil {
+	return nil
+}
+
+func (t *treeStore) updateFlagsTree(flags []*coreTypes.Flag) error {
+	for _, flag := range flags {
+		flagBz, err := codec.GetCodec().Marshal(flag)
+		flagKey := crypto.SHA3Hash([]byte(flag.Name))
+		if err != nil {
+			return err
+		}
+		if err := t.merkleTrees[flagsMerkleTree].Update(flagKey, flagBz); err != nil {
 			return err
 		}
 	}
@@ -356,27 +370,205 @@ func (p *PostgresContext) updateParamsTree() error {
 	return nil
 }

-func (p *PostgresContext) updateFlagsTree() error {
-	flags, err := p.getFlagsUpdated(p.Height)
+// getActorsUpdated is responsible for fetching the actors that have been updated at a given height.
+func (t *treeStore) getActorsUpdated(
+	pgtx pgx.Tx,
+	actorType coreTypes.ActorType,
+	height uint64,
+) ([]*coreTypes.Actor, error) {
+	actorSchema, ok := actorTypeToSchemaName[actorType]
+	if !ok {
+		return nil, fmt.Errorf("no schema found for actor type: %s", actorType)
+	}
+
+	// TECHDEBT (ISSUE #813): Avoid this cast to int64
+	// https://github.com/pokt-network/pocket/issues/813
+	query := actorSchema.GetUpdatedAtHeightQuery(int64(height))
+	rows, err := pgtx.Query(context.TODO(), query)
 	if err != nil {
-		return err
+		return nil, err
 	}
+	defer rows.Close()

-	for _, flag := range flags {
-		flagBz, err := codec.GetCodec().Marshal(flag)
-		flagKey := crypto.SHA3Hash([]byte(flag.Name))
+	addrs := make([][]byte, 0)
+	for rows.Next() {
+		var addr string
+		if err := rows.Scan(&addr); err != nil {
+			return nil, err
+		}
+		addrBz, err := hex.DecodeString(addr)
 		if err != nil {
-			return err
+			return nil, err
 		}
-		if err := p.stateTrees.merkleTrees[flagsMerkleTree].Update(flagKey, flagBz); err != nil {
-			return err
+		addrs = append(addrs, addrBz)
+	}
+
+	actors := make([]*coreTypes.Actor, len(addrs))
+	for i, addr := range addrs {
+		// TECHDEBT #XXX: Avoid this cast to int64
+		actor, err := t.getActor(pgtx, actorSchema, addr, int64(height))
+		if err != nil {
+			return nil, err
 		}
+		actors[i] = actor
+	}
+	rows.Close()

-		// If no errors updating then commit changes to the nodestore
-		if err := p.stateTrees.merkleTrees[flagsMerkleTree].Commit(); err != nil {
-			return err
+	return actors, nil
+}
+
+func (t *treeStore) getAccountsUpdated(
+	pgtx pgx.Tx,
+	acctType ptypes.ProtocolAccountSchema,
+	height uint64,
+) ([]*coreTypes.Account, error) {
+	accounts := []*coreTypes.Account{}
+
+	// TECHDEBT (ISSUE #813): Avoid this cast to int64
+	// https://github.com/pokt-network/pocket/issues/813
+	query := acctType.GetAccountsUpdatedAtHeightQuery(int64(height))
+	rows, err := pgtx.Query(context.TODO(), query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		acc := new(coreTypes.Account)
+		if err := rows.Scan(&acc.Address, &acc.Amount); err != nil {
+			return nil, err
 		}
+		accounts = append(accounts, acc)
 	}

-	return nil
+	return accounts, nil
+}
+
+func (t *treeStore) getTransactions(txi indexer.TxIndexer, height uint64) ([]*coreTypes.IndexedTransaction, error) {
+	// TECHDEBT (ISSUE #813): Avoid this cast to int64
+	// https://github.com/pokt-network/pocket/issues/813
+	indexedTxs, err := txi.GetByHeight(int64(height), false)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get transactions by height: %w", err)
+	}
+	return indexedTxs, nil
+}
+
+// getPools returns the pools updated at the given height
+func (t *treeStore) getPools(pgtx pgx.Tx, height uint64) ([]*coreTypes.Account, error) {
+	pools, err := t.getAccountsUpdated(pgtx, ptypes.Pool, height)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get pools: %w", err)
+	}
+	return pools, nil
+}
+
+// getAccounts returns the list of accounts updated at the provided height
+func (t *treeStore) getAccounts(pgtx pgx.Tx, height uint64) ([]*coreTypes.Account, error) {
+	accounts, err := t.getAccountsUpdated(pgtx, ptypes.Account, height)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get accounts: %w", err)
+	}
+	return accounts, nil
+}
+
+func (t *treeStore) getFlags(pgtx pgx.Tx, height uint64) ([]*coreTypes.Flag, error) {
+	fields := "name,value,enabled"
+	query := fmt.Sprintf("SELECT %s FROM %s WHERE height=%d ORDER BY name ASC", fields, ptypes.FlagsTableName, height)
+	rows, err := pgtx.Query(context.TODO(), query)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get flags: %w", err)
+	}
+	defer rows.Close()
+
+	flagSlice := []*coreTypes.Flag{}
+	for rows.Next() {
+		flag := new(coreTypes.Flag)
+		if err := rows.Scan(&flag.Name, &flag.Value, &flag.Enabled); err != nil {
+			return nil, err
+		}
+		flag.Height = int64(height)
+		flagSlice = append(flagSlice, flag)
+	}
+
+	return flagSlice, nil
+}
+
+func (t *treeStore) getParams(pgtx pgx.Tx, height uint64) ([]*coreTypes.Param, error) {
+	fields := "name,value"
+	query := fmt.Sprintf("SELECT %s FROM %s WHERE height=%d ORDER BY name ASC", fields, ptypes.ParamsTableName, height)
+	rows, err := pgtx.Query(context.TODO(), query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var paramSlice []*coreTypes.Param
+	for rows.Next() {
+		param := new(coreTypes.Param)
+		if err := rows.Scan(&param.Name, &param.Value); err != nil {
+			return nil, err
+		}
+		param.Height = int64(height)
+		paramSlice = append(paramSlice, param)
+	}
+
+	return paramSlice, nil
+}
+
+func (t *treeStore) getActor(tx pgx.Tx, actorSchema ptypes.ProtocolActorSchema, address []byte, height int64) (actor *coreTypes.Actor, err error) {
+	ctx := context.TODO()
+	actor, height, err = t.getActorFromRow(actorSchema.GetActorType(), tx.QueryRow(ctx, actorSchema.GetQuery(hex.EncodeToString(address), height)))
+	if err != nil {
+		return
+	}
+	return t.getChainsForActor(ctx, tx, actorSchema, actor, height)
+}
+
+func (t *treeStore) getActorFromRow(actorType coreTypes.ActorType, row pgx.Row) (actor *coreTypes.Actor, height int64, err error) {
+	actor = &coreTypes.Actor{
+		ActorType: actorType,
+	}
+	err = row.Scan(
+		&actor.Address,
+		&actor.PublicKey,
+		&actor.StakedAmount,
+		&actor.ServiceUrl,
+		&actor.Output,
+		&actor.PausedHeight,
+		&actor.UnstakingHeight,
+		&height)
+	return
+}
+
+func (t *treeStore) getChainsForActor(
+	ctx context.Context,
+	tx pgx.Tx,
+	actorSchema ptypes.ProtocolActorSchema,
+	actor *coreTypes.Actor,
+	height int64,
+) (a *coreTypes.Actor, err error) {
+	if actorSchema.GetChainsTableName() == "" {
+		return actor, nil
+	}
+	rows, err := tx.Query(ctx, actorSchema.GetChainsQuery(actor.Address, height))
+	if err != nil {
+		return actor, err
+	}
+	defer rows.Close()
+
+	var chainAddr string
+	var chainID string
+	var chainEndHeight int64 // DISCUSS: why is this commented as "unused"?
+	for rows.Next() {
+		err = rows.Scan(&chainAddr, &chainID, &chainEndHeight)
+		if err != nil {
+			return
+		}
+		if chainAddr != actor.Address {
+			return actor, fmt.Errorf("unexpected address %s, expected %s when reading chains", chainAddr, actor.Address)
+		}
+		actor.Chains = append(actor.Chains, chainID)
+	}
+	return actor, nil
 }