Decoded Logs

Decoded events logs on Base.

Using Decoded Logs

In general, we recommend using this combination of params and params_keys_mapping on all of your production pipelines, since it guarantees that your query won’t break if the field names ever change

Logs are decoded via topic0, but they do not specify the name of the params. As a result, there may be inconsistencies in the decoded params field while the underlying values is correct.

Field name changes over time are influenced by contract ABIs used during log decoding. We prioritize contract-specific ABIs but may fallback to generic ABIs. Historical records aren't retroactively updated to maintain query consistency.

Using Params Key Mapping

Using Uniswap v3 Swap() event params as an example, we first reference the params field:

{   "amount0": "-718884554",   "amount1": "600000000000000000",   "liquidity": "11511633818000282989",   "recipient": "0xd034d7e8b27b99b5674f2d412584a2897fc87eae",   "sender": "0x68b3465833fb72a70ecdf485e0e4c7bd8665fc45",   "sqrtPriceX96": "2285459885189609648572828648093816",   "tick": "205405" }

Then look at the params_keys_mapping:

[   "sender",   "recipient",   "amount0",   "amount1",   "sqrtPriceX96",   "liquidity",   "tick" ]

From there, rewrite the query using params[params_keys_mapping[index]] syntax:

select 
    params[params_keys_mapping[0]] as sender,
    params[params_keys_mapping[1]] as recipient,
...

Table Columns

Column Name	Description
block_number	The length of the chain, in blocks.
block_timestamp	The time when the block that contains this log was included on the blockchain.
block_hash	Unique identifier of the block that includes this log.
address	The address of the contract that emitted this log.
name	Log event name.
params	Decoded parameters in JSON format.
data	Unindexed data containing further information of the event, encoded in hex.
topic0	The keccak256 hash of a flattened event signature string.
topic1	First indexed topic of the event.
topic2	Second indexed topic of the event
topic3	Third indexed topic of the event.
transaction_from_address	The address of the sending party of this transaction.
transaction_to_address	The address of the receiving party of this transaction.
transaction_hash	Unique identifier of the transaction that this log belongs to.
transaction_index	The position of this transaction in the block that it belongs to. The first transaction has index 0.
log_index	The position of this log in the block that it belongs to. The first log has index 0.
signature	Event log signature.
params_keys_mapping	Mapping of parameter keys in decoding.
interface_id	Interface ID.
_created_at	Timestamp of the entry creation.
_updated_at	Timestamp of the entry update.