Allow set initial memory size

.changeset/dry-moons-smile.md

@@ -0,0 +1,5 @@
+---
+'@electric-sql/pglite': patch
+---
+
+Allow setting initial memory size.

packages/pglite/src/pglite.ts

@@ -300,11 +300,19 @@ export class PGlite
       fsBundleBuffer = buffer
     })
 
+    const wasmMemory = new WebAssembly.Memory({
+      initial: options.initialMemory
+        ? options.initialMemory / (64 * 1024)
+        : 2048,
+      maximum: 32768,
+    })
+
     let emscriptenOpts: Partial<PostgresMod> = {
       thisProgram: postgresExePath,
       WASM_PREFIX,
       arguments: args,
       noExitRuntime: true,
+      wasmMemory: wasmMemory,
       // Provide a stdin that returns EOF to avoid browser prompt
       stdin: () => null,
       print: (text: string) => {

packages/pglite/src/postgresMod.ts

@@ -22,6 +22,7 @@ export interface PostgresMod
   thisProgram: string
   stdin: (() => number | null) | null
   FS: FS
+  wasmMemory: WebAssembly.Memory
   PROXYFS: Emscripten.FileSystemType
   WASM_PREFIX: string
   pg_extensions: Record<string, Promise<Blob | null>>

packages/pglite/tests/basic.test.ts

@@ -651,6 +651,17 @@ await testEsmCjsAndDTC(async (importType) => {
       })
     })
 
+    it('initialMemory works', async () => {
+      const wantedMemSize = 512 * 1024 * 1024
+      const db = await PGlite.create({
+        initialMemory: wantedMemSize,
+      })
+
+      const instanceMemSize = db.Module.HEAPU8.buffer.byteLength
+
+      expect(instanceMemSize).toEqual(wantedMemSize)
+    })
+
     // this tests the parameter 'max_parallel_workers_per_gather=0',
     it('it shouldnt use parallel workers on gather', async () => {
       const db = await PGlite.create()