perf: improve messages queries

[wa0x6e]

Fixes https://github.com/snapshot-labs/workflow/issues/585

This PR improves upon the previous fix.

We will now use the query hint use index when the query is filtered by spaces, and not ordered by mci (which is an indexed column).

[ChaituVR]

I tried query with

query BatchLatestMCI {
_a42edf54dd93220a6f8a410c0919c77a67d2feef8a8295123eabe17426853284: messages(where: {
      space: "swarmfoundation.eth",
      type_in: ["proposal", "delete-proposal"],
      },
      first: 1,
      orderBy: "mci",
      orderDirection: desc) {
        mci
      }
_f88a5f7ff244b35c39427d542ba718362b413eec175276b193d459404dd1d0fc: messages(where: {
      space: "etherfi-dao.eth",
      type_in: ["proposal", "delete-proposal"],
      },
      first: 1,
      orderBy: "mci",
      orderDirection: desc) {
        mci
      }
}

it is still slow somehow 🤔 taking forever, is it same for you?

[wa0x6e]

An immediate working fix is changing the orderBy to timestamp (which is essentially the same thing), which return in a relatively acceptable time (~10s)

[wa0x6e]

Aside from that, nothing really can be done, beside adding more index

[ChaituVR]

Aside from that, nothing really can be done, beside adding more index

Adding space + mci index can help? may also need space + type + mci

[wa0x6e]

adding any composite index will help. Issue is that the size with the size of our table, it will takes few hours, and lot of spaces (like 30-50 gb)

[ChaituVR]

hmmm yeah, maybe we can switch index like this, this is much faster

diff --git a/src/graphql/operations/messages.ts b/src/graphql/operations/messages.ts
index 9dd9fa7..797fe02 100644
--- a/src/graphql/operations/messages.ts
+++ b/src/graphql/operations/messages.ts
@@ -27,11 +27,16 @@ export default async function (parent, args) {
   orderDirection = orderDirection.toUpperCase();
   if (!['ASC', 'DESC'].includes(orderDirection)) orderDirection = 'DESC';
 
-  // Use space index when filtering by space and not ordering by mci
-  const useSpaceIndex =
-    where.space && orderBy !== 'm.mci' ? 'USE INDEX (space)' : '';
+  // Optimized index selection for better performance
+  let indexHint = '';
+  if (where.space) {
+    indexHint = 'USE INDEX (space)';
+  } else if (orderBy === 'm.mci') {
+    indexHint = 'USE INDEX (mci)';
+  }
+
   const query = `
-    SELECT m.* FROM messages m ${useSpaceIndex}
+    SELECT m.* FROM messages m ${indexHint}
     WHERE 1=1 ${queryStr}
     ORDER BY ${orderBy} ${orderDirection} LIMIT ?, ?
   `;

[wa0x6e]

Mci index should already be the one used by default, since it's the primary key. Do you notice difference by using it explicitly?

[ChaituVR]

hmm looks like above queries are resolving fast on hub.snapshot.org 😅 i tried different spaces and they are working as well. weird