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Parse.com vs Parse Server - Slower Queries #1564
Description
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Environment Setup
Environments
- parse.com with mlab mongo
- parse server 2.2.7 with mlab mongo
Steps to reproduce
Query 1) and 2) with a where, limit and order clause. Example:
/classes/albums
{"where":{"artists":"Band"},"limit":100,"order":"-releaseDateValue"}
- parse.com generates a query that takes 524 ms
- parse server generates a more complicated / nested query that takes 1134 ms
Logs/Trace
- parse.com query
{ $query: { artists: "Band", _rperm: { $in: [ null, "*" ] } }, $orderby: { releaseDateValue: -1 }, $maxScan: 500000, $maxTimeMS: 29000, $comment: "queryhash:89c4fc26d1926094198e827388a261e8" } planSummary: COLLSCAN, COLLSCAN ntoreturn:100 ntoskip:0 nscanned:0 nscannedObjects:128120 scanAndOrder:1 keyUpdates:0 writeConflicts:0 numYields:1001 nreturned:51 reslen:992098 locks:{ Global: { acquireCount: { r: 2004 } }, MMAPV1Journal: { acquireCount: { r: 1002 } }, Database: { acquireCount: { r: 1002 } }, Collection: { acquireCount: { R: 1002 } } } 524ms
- parse server 2.2.7
{ $query: { $and: [ { artists: { $all: [ "Band" ] } }, { $or: [ { _rperm: { $exists: false } }, { _rperm: { $in: [ "*" ] } } ] } ] } } planSummary: COLLSCAN, COLLSCAN ntoreturn:100 ntoskip:0 nscanned:0 nscannedObjects:128120 scanAndOrder:1 keyUpdates:0 writeConflicts:0 numYields:1001 nreturned:51 reslen:992098 locks:{ Global: { acquireCount: { r: 2004 } }, MMAPV1Journal: { acquireCount: { r: 1002 } }, Database: { acquireCount: { r: 1002 } }, Collection: { acquireCount: { R: 1002 } } } 1134ms
Activity
blacha commentedon Apr 20, 2016
This may be unrelated, but it looks like you don't have a index on
artist, the plan beingCOLLSCANandnscannedObjectsbeing soo high seems like its doing a full table scan.Are these two queries being run against the same database in mlab?
jobacao commentedon Apr 20, 2016
The two (parse.com/parse server) queries are against the same mlab db. Any ideas on why parse.com and parse server are generating 2 different queries?
drew-gross commentedon Apr 20, 2016
Parse Server is missing some optimizations present in Parse.com. We'll continue to improve perf over time :) thanks @blacha for fixing one of the issues from here!