diff --git a/apps/cic-eth/cic_eth/db/models/base.py b/apps/cic-eth/cic_eth/db/models/base.py
index 16d01d0..353c67c 100644
--- a/apps/cic-eth/cic_eth/db/models/base.py
+++ b/apps/cic-eth/cic_eth/db/models/base.py
@@ -6,6 +6,11 @@ from sqlalchemy import Column, Integer
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
+from sqlalchemy.pool import (
+        StaticPool,
+        QueuePool,
+        AssertionPool,
+        )
 
 logg = logging.getLogger()
 
@@ -49,7 +54,7 @@ class SessionBase(Model):
 
 
     @staticmethod
-    def connect(dsn, debug=False):
+    def connect(dsn, pool_size=8, debug=False):
         """Create new database connection engine and connect to database backend.
 
         :param dsn: DSN string defining connection.
@@ -57,14 +62,28 @@ class SessionBase(Model):
         """
         e = None
         if SessionBase.poolable:
-            e = create_engine(
-                    dsn,
-                    max_overflow=50,
-                    pool_pre_ping=True,
-                    pool_size=20,
-                    pool_recycle=10,
-                    echo=debug,
-                )
+            poolclass = QueuePool
+            if pool_size > 1:
+                e = create_engine(
+                        dsn,
+                        max_overflow=pool_size*3,
+                        pool_pre_ping=True,
+                        pool_size=pool_size,
+                        pool_recycle=60,
+                        poolclass=poolclass,
+                        echo=debug,
+                    )
+            else:
+                if debug:
+                    poolclass = AssertionPool
+                else:
+                    poolclass = StaticPool
+
+                e = create_engine(
+                        dsn,
+                        poolclass=poolclass,
+                        echo=debug,
+                    )
         else:
             e = create_engine(
                     dsn,
diff --git a/apps/cic-eth/cic_eth/db/models/tx.py b/apps/cic-eth/cic_eth/db/models/tx.py
index 98a36ba..5eb46a7 100644
--- a/apps/cic-eth/cic_eth/db/models/tx.py
+++ b/apps/cic-eth/cic_eth/db/models/tx.py
@@ -85,18 +85,18 @@ class TxCache(SessionBase):
         :param tx_hash_new: tx hash to associate the copied entry with
         :type tx_hash_new: str, 0x-hex
         """
-        localsession = session
-        if localsession == None:
-            localsession = SessionBase.create_session()
-
+        localsession = SessionBase.bind_session(session)
+        
         q = localsession.query(TxCache)
         q = q.join(Otx)
         q = q.filter(Otx.tx_hash==tx_hash_original)
         txc = q.first()
 
         if txc == None:
+            SessionBase.release_session(localsession)
             raise NotLocalTxError('original {}'.format(tx_hash_original))
         if txc.block_number != None:
+            SessionBase.release_session(localsession)
             raise TxStateChangeError('cannot clone tx cache of confirmed tx {}'.format(tx_hash_original))
 
         q = localsession.query(Otx)
@@ -104,6 +104,7 @@ class TxCache(SessionBase):
         otx = q.first()
 
         if otx == None:
+            SessionBase.release_session(localsession)
             raise NotLocalTxError('new {}'.format(tx_hash_new))
 
         txc_new = TxCache(
@@ -118,15 +119,14 @@ class TxCache(SessionBase):
         localsession.add(txc_new)
         localsession.commit()
 
-        if session == None:
-            localsession.close()
+        SessionBase.release_session(localsession)
 
 
-    def __init__(self, tx_hash, sender, recipient, source_token_address, destination_token_address, from_value, to_value, block_number=None, tx_index=None):
-        session = SessionBase.create_session()
-        tx = session.query(Otx).filter(Otx.tx_hash==tx_hash).first()
+    def __init__(self, tx_hash, sender, recipient, source_token_address, destination_token_address, from_value, to_value, block_number=None, tx_index=None, session=None):
+        localsession = SessionBase.bind_session(session)
+        tx = localsession.query(Otx).filter(Otx.tx_hash==tx_hash).first()
         if tx == None:
-            session.close()
+            SessionBase.release_session(localsession)
             raise FileNotFoundError('outgoing transaction record unknown {} (add a Tx first)'.format(tx_hash))
         self.otx_id = tx.id
 
@@ -143,4 +143,5 @@ class TxCache(SessionBase):
         self.date_updated = self.date_created
         self.date_checked = self.date_created
 
+        SessionBase.release_session(localsession)
 
diff --git a/apps/cic-eth/cic_eth/eth/account.py b/apps/cic-eth/cic_eth/eth/account.py
index 01a9f6e..a3b2322 100644
--- a/apps/cic-eth/cic_eth/eth/account.py
+++ b/apps/cic-eth/cic_eth/eth/account.py
@@ -304,6 +304,8 @@ def cache_gift_data(
     tx = unpack_signed_raw_tx(tx_signed_raw_bytes, chain_spec.chain_id())
     tx_data = unpack_gift(tx['data'])
 
+    session = SessionBase.create_session()
+
     tx_cache = TxCache(
         tx_hash_hex,
         tx['from'],
@@ -312,9 +314,9 @@ def cache_gift_data(
         zero_address,
         0,
         0,
+        session=session,
             )
 
-    session = SessionBase.create_session()
     session.add(tx_cache)
     session.commit()
     cache_id = tx_cache.id
@@ -347,6 +349,7 @@ def cache_account_data(
     tx = unpack_signed_raw_tx(tx_signed_raw_bytes, chain_spec.chain_id())
     tx_data = unpack_register(tx['data'])
 
+    session = SessionBase.create_session()
     tx_cache = TxCache(
         tx_hash_hex,
         tx['from'],
@@ -355,9 +358,8 @@ def cache_account_data(
         zero_address,
         0,
         0,
+        session=session,
             )
-
-    session = SessionBase.create_session()
     session.add(tx_cache)
     session.commit()
     cache_id = tx_cache.id
diff --git a/apps/cic-eth/cic_eth/eth/token.py b/apps/cic-eth/cic_eth/eth/token.py
index 60ffec9..6cbe088 100644
--- a/apps/cic-eth/cic_eth/eth/token.py
+++ b/apps/cic-eth/cic_eth/eth/token.py
@@ -381,6 +381,7 @@ def cache_transfer_data(
         tx['to'],
         tx_data['amount'],
         tx_data['amount'],
+        session=session,
             )
     session.add(tx_cache)
     session.commit()
@@ -440,6 +441,7 @@ def cache_approve_data(
         tx['to'],
         tx_data['amount'],
         tx_data['amount'],
+        session=session,
             )
     session.add(tx_cache)
     session.commit()
diff --git a/apps/cic-eth/cic_eth/eth/tx.py b/apps/cic-eth/cic_eth/eth/tx.py
index c4a3fca..ce16145 100644
--- a/apps/cic-eth/cic_eth/eth/tx.py
+++ b/apps/cic-eth/cic_eth/eth/tx.py
@@ -78,7 +78,6 @@ def check_gas(self, tx_hashes, chain_str, txs=[], address=None, gas_required=Non
 
     # TODO: it should not be necessary to pass address explicitly, if not passed should be derived from the tx
     balance = c.w3.eth.getBalance(address) 
-    logg.debug('check gas txs {}'.format(tx_hashes))
     logg.debug('address {} has gas {} needs {}'.format(address, balance, gas_required))
 
     if gas_required > balance:
@@ -126,7 +125,6 @@ def check_gas(self, tx_hashes, chain_str, txs=[], address=None, gas_required=Non
             queue=queue,
             )
         ready_tasks.append(s)
-    logg.debug('tasks {}'.format(ready_tasks))
     celery.group(ready_tasks)()
 
     return txs
@@ -143,7 +141,6 @@ def hashes_to_txs(self, tx_hashes):
     :returns: Signed raw transactions
     :rtype: list of str, 0x-hex
     """
-    #logg = celery_app.log.get_default_logger()
     if len(tx_hashes) == 0:
         raise ValueError('no transaction to send')
 
@@ -351,15 +348,12 @@ def send(self, txs, chain_str):
     tx_hash_hex = tx_hash.hex()
 
     queue = self.request.delivery_info.get('routing_key', None)
-    if queue == None:
-        logg.debug('send tx {} has no queue', tx_hash)
 
     c = RpcClient(chain_spec)
     r = None
     try:
         r = c.w3.eth.send_raw_transaction(tx_hex)
     except Exception as e:
-        logg.debug('e {}'.format(e))
         raiser = ParityNodeHandler(chain_spec, queue)
         (t, e, m) = raiser.handle(e, tx_hash_hex, tx_hex)
         raise e(m)
@@ -423,7 +417,7 @@ def refill_gas(self, recipient_address, chain_str):
     gas_price = c.gas_price()
     gas_limit = c.default_gas_limit
     refill_amount = c.refill_amount()
-    logg.debug('gas price {} nonce {}'.format(gas_price, nonce))
+    logg.debug('tx send gas price {} nonce {}'.format(gas_price, nonce))
 
     # create and sign transaction
     tx_send_gas = {
@@ -436,7 +430,6 @@ def refill_gas(self, recipient_address, chain_str):
                 'value': refill_amount,
                 'data': '',
             }
-    logg.debug('txsend_gas {}'.format(tx_send_gas))
     tx_send_gas_signed = c.w3.eth.sign_transaction(tx_send_gas)
     tx_hash = web3.Web3.keccak(hexstr=tx_send_gas_signed['raw'])
     tx_hash_hex = tx_hash.hex()
@@ -487,11 +480,14 @@ def resend_with_higher_gas(self, txold_hash_hex, chain_str, gas=None, default_fa
     :rtype: str, 0x-hex
     """
     session = SessionBase.create_session()
-    otx = session.query(Otx).filter(Otx.tx_hash==txold_hash_hex).first()
-    if otx == None:
-        session.close()
-        raise NotLocalTxError(txold_hash_hex)
+
+    
+    q = session.query(Otx)
+    q = q.filter(Otx.tx_hash==txold_hash_hex)
+    otx = q.first()
     session.close()
+    if otx == None:
+        raise NotLocalTxError(txold_hash_hex)
 
     chain_spec = ChainSpec.from_chain_str(chain_str)
     c = RpcClient(chain_spec)
@@ -508,7 +504,7 @@ def resend_with_higher_gas(self, txold_hash_hex, chain_str, gas=None, default_fa
     else:
         gas_price = c.gas_price()
         if tx['gasPrice'] > gas_price:
-            logg.warning('Network gas price {} is lower than overdue tx gas price {}'.format(gas_price, tx['gasPrice']))
+            logg.info('Network gas price {} is lower than overdue tx gas price {}'.format(gas_price, tx['gasPrice']))
             #tx['gasPrice'] = int(tx['gasPrice'] * default_factor)
             tx['gasPrice'] += 1
         else:
@@ -518,9 +514,6 @@ def resend_with_higher_gas(self, txold_hash_hex, chain_str, gas=None, default_fa
             else:
                 tx['gasPrice'] = new_gas_price
 
-    logg.debug('after {}'.format(tx))
-
-    #(tx_hash_hex, tx_signed_raw_hex) = sign_and_register_tx(tx, chain_str, queue)
     (tx_hash_hex, tx_signed_raw_hex) = sign_tx(tx, chain_str)
     queue_create(
         tx['nonce'],
@@ -540,6 +533,7 @@ def resend_with_higher_gas(self, txold_hash_hex, chain_str, gas=None, default_fa
             queue=queue,
             )
     s.apply_async()
+
     return tx_hash_hex
 
 
@@ -602,7 +596,9 @@ def resume_tx(self, txpending_hash_hex, chain_str):
     chain_spec = ChainSpec.from_chain_str(chain_str)
 
     session = SessionBase.create_session()
-    r = session.query(Otx.signed_tx).filter(Otx.tx_hash==txpending_hash_hex).first()
+    q = session.query(Otx.signed_tx)
+    q = q.filter(Otx.tx_hash==txpending_hash_hex)
+    r = q.first()
     session.close()
     if r == None:
         raise NotLocalTxError(txpending_hash_hex)
diff --git a/apps/cic-eth/cic_eth/queue/tx.py b/apps/cic-eth/cic_eth/queue/tx.py
index 94ab14b..9269bd8 100644
--- a/apps/cic-eth/cic_eth/queue/tx.py
+++ b/apps/cic-eth/cic_eth/queue/tx.py
@@ -35,8 +35,7 @@ celery_app = celery.current_app
 logg = logging.getLogger()
 
 
-@celery_app.task()
-def create(nonce, holder_address, tx_hash, signed_tx, chain_str, obsolete_predecessors=True):
+def create(nonce, holder_address, tx_hash, signed_tx, chain_str, obsolete_predecessors=True, session=None):
     """Create a new transaction queue record.
 
     :param nonce: Transaction nonce
@@ -52,10 +51,10 @@ def create(nonce, holder_address, tx_hash, signed_tx, chain_str, obsolete_predec
     :returns: transaction hash
     :rtype: str, 0x-hash
     """
-    session = SessionBase.create_session()
+    session = SessionBase.bind_session(session)
     lock = Lock.check_aggregate(chain_str, LockEnum.QUEUE, holder_address, session=session) 
     if lock > 0:
-        session.close()
+        SessionBase.release_session(session)
         raise LockedError(lock)
 
     o = Otx.add(
@@ -81,7 +80,7 @@ def create(nonce, holder_address, tx_hash, signed_tx, chain_str, obsolete_predec
             otx.cancel(confirmed=False, session=session)
 
     session.commit()
-    session.close()
+    SessionBase.release_session(session)
     logg.debug('queue created nonce {} from {} hash {}'.format(nonce, holder_address, tx_hash))
     return tx_hash
 
@@ -100,7 +99,9 @@ def set_sent_status(tx_hash, fail=False):
     :rtype: boolean
     """
     session = SessionBase.create_session()
-    o = session.query(Otx).filter(Otx.tx_hash==tx_hash).first()
+    q = session.query(Otx)
+    q = q.filter(Otx.tx_hash==tx_hash)
+    o = q.first()
     if o == None:
         logg.warning('not local tx, skipping {}'.format(tx_hash))
         session.close()
@@ -454,6 +455,7 @@ def get_tx(tx_hash):
     session = SessionBase.create_session()
     tx = session.query(Otx).filter(Otx.tx_hash==tx_hash).first()
     if tx == None:
+        session.close()
         raise NotLocalTxError('queue does not contain tx hash {}'.format(tx_hash))
 
     o = {
@@ -498,7 +500,7 @@ def get_nonce_tx(nonce, sender, chain_id):
 
 
 # TODO: pass chain spec instead of chain id
-def get_paused_txs(status=None, sender=None, chain_id=0):
+def get_paused_txs(status=None, sender=None, chain_id=0, session=None):
     """Returns not finalized transactions that have been attempted sent without success.
 
     :param status: If set, will return transactions with this local queue status only
@@ -511,12 +513,13 @@ def get_paused_txs(status=None, sender=None, chain_id=0):
     :returns: Transactions
     :rtype: dict, with transaction hash as key, signed raw transaction as value
     """
-    session = SessionBase.create_session()
+    session = SessionBase.bind_session(session)
     q = session.query(Otx)
 
     if status != None:
         #if status == StatusEnum.PENDING or status >= StatusEnum.SENT:
         if status == StatusEnum.PENDING or status & StatusBits.IN_NETWORK or not is_alive(status):
+            SessionBase.release_session(session)
             raise ValueError('not a valid paused tx value: {}'.format(status))
         q = q.filter(Otx.status.op('&')(status.value)==status.value)
         q = q.join(TxCache)
@@ -536,12 +539,12 @@ def get_paused_txs(status=None, sender=None, chain_id=0):
             #gas += tx['gas'] * tx['gasPrice']
             txs[r.tx_hash] = r.signed_tx
 
-    session.close()
+    SessionBase.release_session(session)
 
     return txs
 
 
-def get_status_tx(status, before=None, exact=False, limit=0):
+def get_status_tx(status, before=None, exact=False, limit=0, session=None):
     """Retrieve transaction with a specific queue status.
 
     :param status: Status to match transactions with
@@ -554,7 +557,7 @@ def get_status_tx(status, before=None, exact=False, limit=0):
     :rtype: list of cic_eth.db.models.otx.Otx
     """
     txs = {}
-    session = SessionBase.create_session()
+    session = SessionBase.bind_session(session)
     q = session.query(Otx)
     q = q.join(TxCache)
     q = q.filter(TxCache.date_updated<before)
@@ -568,12 +571,12 @@ def get_status_tx(status, before=None, exact=False, limit=0):
             break
         txs[o.tx_hash] = o.signed_tx
         i += 1
-    session.close()
+    SessionBase.release_session(session)
     return txs
 
 
 # TODO: move query to model
-def get_upcoming_tx(status=StatusEnum.READYSEND, recipient=None, before=None, chain_id=0):
+def get_upcoming_tx(status=StatusEnum.READYSEND, recipient=None, before=None, chain_id=0, session=None):
     """Returns the next pending transaction, specifically the transaction with the lowest nonce, for every recipient that has pending transactions.
 
     Will omit addresses that have the LockEnum.SEND bit in Lock set.
@@ -592,7 +595,7 @@ def get_upcoming_tx(status=StatusEnum.READYSEND, recipient=None, before=None, ch
     :returns: Transactions
     :rtype: dict, with transaction hash as key, signed raw transaction as value
     """
-    session = SessionBase.create_session()
+    session = SessionBase.bind_session(session)
     q_outer = session.query(
             TxCache.sender,
             func.min(Otx.nonce).label('nonce'),
@@ -602,6 +605,7 @@ def get_upcoming_tx(status=StatusEnum.READYSEND, recipient=None, before=None, ch
     q_outer = q_outer.filter(or_(Lock.flags==None, Lock.flags.op('&')(LockEnum.SEND.value)==0))
 
     if not is_alive(status):
+        SessionBase.release_session(session)
         raise ValueError('not a valid non-final tx value: {}'.format(status))
     if status == StatusEnum.PENDING:
         q_outer = q_outer.filter(Otx.status==status.value)
@@ -643,7 +647,7 @@ def get_upcoming_tx(status=StatusEnum.READYSEND, recipient=None, before=None, ch
         session.add(o)
         session.commit()
 
-    session.close()
+    SessionBase.release_session(session)
 
     return txs
 
diff --git a/apps/cic-eth/cic_eth/runnable/daemons/filters/callback.py b/apps/cic-eth/cic_eth/runnable/daemons/filters/callback.py
index a43ce31..c70ddc7 100644
--- a/apps/cic-eth/cic_eth/runnable/daemons/filters/callback.py
+++ b/apps/cic-eth/cic_eth/runnable/daemons/filters/callback.py
@@ -37,7 +37,7 @@ class CallbackFilter(SyncFilter):
                 transfer_type,
                 int(rcpt.status == 0),
             ],
-            queue=tc.queue,
+            queue=self.queue,
             )
 #        s_translate = celery.signature(
 #            'cic_eth.ext.address.translate',
@@ -82,7 +82,7 @@ class CallbackFilter(SyncFilter):
         return (transfer_type, transfer_data)
 
 
-    def filter(self, w3, tx, rcpt, chain_spec):
+    def filter(self, w3, tx, rcpt, chain_spec, session=None):
         logg.debug('applying callback filter "{}:{}"'.format(self.queue, self.method))
         chain_str = str(chain_spec)
 
diff --git a/apps/cic-eth/cic_eth/runnable/daemons/filters/gas.py b/apps/cic-eth/cic_eth/runnable/daemons/filters/gas.py
index a3cf1d3..4b31237 100644
--- a/apps/cic-eth/cic_eth/runnable/daemons/filters/gas.py
+++ b/apps/cic-eth/cic_eth/runnable/daemons/filters/gas.py
@@ -17,29 +17,31 @@ logg = logging.getLogger()
 
 class GasFilter(SyncFilter):
 
-    def __init__(self, gas_provider):
+    def __init__(self, gas_provider, queue=None):
+        self.queue = queue
         self.gas_provider = gas_provider
 
 
-    def filter(self, w3, tx, rcpt, chain_str):
+    def filter(self, w3, tx, rcpt, chain_str, session=None):
         logg.debug('applying gas filter')
         tx_hash_hex = tx.hash.hex()
         if tx['value'] > 0:
             logg.debug('gas refill tx {}'.format(tx_hash_hex))
-            session = SessionBase.create_session()
+            session = SessionBase.bind_session(session)
             q = session.query(TxCache.recipient)
             q = q.join(Otx)
             q = q.filter(Otx.tx_hash==tx_hash_hex)
             r = q.first()
 
-            session.close()
-
             if r == None:
                 logg.warning('unsolicited gas refill tx {}'.format(tx_hash_hex))
+                SessionBase.release_session(session)
                 return
 
             chain_spec = ChainSpec.from_chain_str(chain_str)
-            txs = get_paused_txs(StatusEnum.WAITFORGAS, r[0], chain_spec.chain_id())
+            txs = get_paused_txs(StatusEnum.WAITFORGAS, r[0], chain_spec.chain_id(), session=session)
+
+            SessionBase.release_session(session)
 
             if len(txs) > 0:
                 logg.info('resuming gas-in-waiting txs for {}: {}'.format(r[0], txs.keys()))
@@ -49,6 +51,6 @@ class GasFilter(SyncFilter):
                         r[0],
                         0,
                         tx_hashes_hex=list(txs.keys()),
-                        queue=queue,
+                        queue=self.queue,
                 )
                 s.apply_async()
diff --git a/apps/cic-eth/cic_eth/runnable/daemons/filters/register.py b/apps/cic-eth/cic_eth/runnable/daemons/filters/register.py
index 180cdca..3c003d3 100644
--- a/apps/cic-eth/cic_eth/runnable/daemons/filters/register.py
+++ b/apps/cic-eth/cic_eth/runnable/daemons/filters/register.py
@@ -15,7 +15,7 @@ account_registry_add_log_hash = '0x5ed3bdd47b9af629827a8d129aa39c870b10c03f0153f
 
 class RegistrationFilter(SyncFilter):
 
-    def filter(self, w3, tx, rcpt, chain_spec):
+    def filter(self, w3, tx, rcpt, chain_spec, session=None):
         logg.debug('applying registration filter')
         registered_address = None
         for l in rcpt['logs']:
diff --git a/apps/cic-eth/cic_eth/runnable/daemons/filters/tx.py b/apps/cic-eth/cic_eth/runnable/daemons/filters/tx.py
index 6a645ff..ceab9a1 100644
--- a/apps/cic-eth/cic_eth/runnable/daemons/filters/tx.py
+++ b/apps/cic-eth/cic_eth/runnable/daemons/filters/tx.py
@@ -6,6 +6,7 @@ import celery
 
 # local imports
 from cic_eth.db.models.otx import Otx
+from cic_eth.db.models.base import SessionBase
 from .base import SyncFilter
 
 logg = logging.getLogger()
@@ -17,15 +18,17 @@ class TxFilter(SyncFilter):
         self.queue = queue
 
 
-    def filter(self, w3, tx, rcpt, chain_spec):
+    def filter(self, w3, tx, rcpt, chain_spec, session=None):
+        session = SessionBase.bind_session(session)
         logg.debug('applying tx filter')
         tx_hash_hex = tx.hash.hex()
-        otx = Otx.load(tx_hash_hex)
+        otx = Otx.load(tx_hash_hex, session=session)
+        SessionBase.release_session(session)
         if otx == None:
             logg.debug('tx {} not found locally, skipping'.format(tx_hash_hex))
             return None
         logg.info('otx found {}'.format(otx.tx_hash))
-        s = celery.siignature(
+        s = celery.signature(
                 'cic_eth.queue.tx.set_final_status',
                 [
                     tx_hash_hex,
diff --git a/apps/cic-eth/cic_eth/runnable/daemons/manager.py b/apps/cic-eth/cic_eth/runnable/daemons/manager.py
index bb85c46..db83460 100644
--- a/apps/cic-eth/cic_eth/runnable/daemons/manager.py
+++ b/apps/cic-eth/cic_eth/runnable/daemons/manager.py
@@ -118,7 +118,7 @@ declarator = CICRegistry.get_contract(chain_spec, 'AddressDeclarator', interface
 
 
 dsn = dsn_from_config(config)
-SessionBase.connect(dsn)
+SessionBase.connect(dsn, pool_size=1, debug=config.true('DATABASE_DEBUG'))
 
 
 def main():
@@ -180,7 +180,7 @@ def main():
 
     registration_filter = RegistrationFilter()
 
-    gas_filter = GasFilter(c.gas_provider())
+    gas_filter = GasFilter(c.gas_provider(), queue)
 
     i = 0
     for syncer in syncers:
diff --git a/apps/cic-eth/cic_eth/runnable/daemons/tasker.py b/apps/cic-eth/cic_eth/runnable/daemons/tasker.py
index 6eb343c..6b9c4bf 100644
--- a/apps/cic-eth/cic_eth/runnable/daemons/tasker.py
+++ b/apps/cic-eth/cic_eth/runnable/daemons/tasker.py
@@ -78,7 +78,7 @@ logg.debug('config loaded from {}:\n{}'.format(args.c, config))
 
 # connect to database
 dsn = dsn_from_config(config)
-SessionBase.connect(dsn)
+SessionBase.connect(dsn, pool_size=8, debug=config.true('DATABASE_DEBUG'))
 
 # verify database connection with minimal sanity query
 session = SessionBase.create_session()
@@ -179,7 +179,6 @@ def web3ext_constructor():
     return (blockchain_provider, w3)
 RpcClient.set_constructor(web3ext_constructor) 
 
-logg.info('ccc {}'.format(config.store['TASKS_TRACE_QUEUE_STATUS']))
 Otx.tracing = config.true('TASKS_TRACE_QUEUE_STATUS')
 
 
diff --git a/apps/cic-eth/cic_eth/sync/backend.py b/apps/cic-eth/cic_eth/sync/backend.py
index af58be9..56f08f3 100644
--- a/apps/cic-eth/cic_eth/sync/backend.py
+++ b/apps/cic-eth/cic_eth/sync/backend.py
@@ -28,20 +28,25 @@ class SyncerBackend:
     def connect(self):
         """Loads the state of the syncer session with the given id.
         """
-        self.db_session = SessionBase.create_session()
+        if self.db_session == None:
+            self.db_session = SessionBase.create_session()
         q = self.db_session.query(BlockchainSync)
         q = q.filter(BlockchainSync.id==self.object_id)
         self.db_object = q.first()
         if self.db_object == None:
+            self.disconnect()
             raise ValueError('sync entry with id {} not found'.format(self.object_id))
+        return self.db_session
 
 
     def disconnect(self):
         """Commits state of sync to backend.
         """
-        self.db_session.add(self.db_object)
-        self.db_session.commit()
-        self.db_session.close()
+        if self.db_session != None:
+            self.db_session.add(self.db_object)
+            self.db_session.commit()
+            self.db_session.close()
+            self.db_session = None
        
 
     def chain(self):
diff --git a/apps/cic-eth/cic_eth/sync/mined.py b/apps/cic-eth/cic_eth/sync/mined.py
index 616eea5..4481bb2 100644
--- a/apps/cic-eth/cic_eth/sync/mined.py
+++ b/apps/cic-eth/cic_eth/sync/mined.py
@@ -56,7 +56,8 @@ class MinedSyncer(Syncer):
             # TODO: ensure filter loop can complete on graceful shutdown
             for f in self.filter:
                 #try:
-                task_uuid = f(w3, tx, rcpt, self.chain())
+                session = self.bc_cache.connect()
+                task_uuid = f(w3, tx, rcpt, self.chain(), session)
                 #except Exception as e:
                 #    logg.error('error in filter {} tx {}: {}'.format(f, tx_hash_hex, e))
                 #    continue
diff --git a/apps/cic-eth/cic_eth/version.py b/apps/cic-eth/cic_eth/version.py
index 14d75c3..f782394 100644
--- a/apps/cic-eth/cic_eth/version.py
+++ b/apps/cic-eth/cic_eth/version.py
@@ -10,7 +10,7 @@ version = (
         0,
         10,
         0,
-        'alpha.26',
+        'alpha.27',
         )
 
 version_object = semver.VersionInfo(
diff --git a/docker-compose.yml b/docker-compose.yml
index 7433730..2c54eae 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -212,6 +212,7 @@ services:
       DATABASE_PORT: ${DATABASE_PORT:-5432}
       DATABASE_ENGINE: ${DATABASE_ENGINE:-postgres}
       DATABASE_DRIVER: ${DATABASE_DRIVER:-psycopg2}
+      DATABASE_DEBUG: ${DATABASE_DEBUG:-0}
       PGPASSWORD: ${DATABASE_PASSWORD:-tralala}
       CIC_CHAIN_SPEC: ${CIC_CHAIN_SPEC:-Bloxberg:8996}
       BANCOR_DIR: ${BANCOR_DIR:-/usr/local/share/cic/bancor}
@@ -252,6 +253,8 @@ services:
       DATABASE_PORT: ${DATABASE_PORT:-5432}
       DATABASE_ENGINE: ${DATABASE_ENGINE:-postgres}
       DATABASE_DRIVER: ${DATABASE_DRIVER:-psycopg2}
+        #DATABASE_DEBUG: ${DATABASE_DEBUG:-0}
+      DATABASE_DEBUG: 1
       CIC_CHAIN_SPEC: ${CIC_CHAIN_SPEC:-Bloxberg:8996}
       CIC_REGISTRY_ADDRESS: $CIC_REGISTRY_ADDRESS
         #BANCOR_DIR: $BANCOR_DIR
@@ -288,6 +291,7 @@ services:
       DATABASE_PORT: ${DATABASE_PORT:-5432}
       DATABASE_ENGINE: ${DATABASE_ENGINE:-postgres}
       DATABASE_DRIVER: ${DATABASE_DRIVER:-psycopg2}
+      DATABASE_DEBUG: ${DATABASE_DEBUG:-0}
       CIC_CHAIN_SPEC: ${CIC_CHAIN_SPEC:-Bloxberg:8996}
       CIC_REGISTRY_ADDRESS: $CIC_REGISTRY_ADDRESS
         #BANCOR_DIR: $BANCOR_DIR
@@ -324,6 +328,7 @@ services:
       DATABASE_PORT: ${DATABASE_PORT:-5432}
       DATABASE_ENGINE: ${DATABASE_ENGINE:-postgres}
       DATABASE_DRIVER: ${DATABASE_DRIVER:-psycopg2}
+      DATABASE_DEBUG: ${DATABASE_DEBUG:-0}
       CIC_CHAIN_SPEC: ${CIC_CHAIN_SPEC:-Bloxberg:8996}
       CIC_REGISTRY_ADDRESS: $CIC_REGISTRY_ADDRESS
         #BANCOR_DIR: $BANCOR_DIR