MYSQL error 1069: Too many keys specified; max 64 keys allowed in query

[RieksJ]

Consider the following script:

CONTEXT Issue758

r1  :: C * C1 [UNI]   r2  :: C * C2 [UNI]   r3  :: C * C3 [UNI]   r4  :: C * C4 [UNI]   r5  :: C * C5 [UNI]
r6  :: C * C6 [UNI]   r7  :: C * C7 [UNI]   r8  :: C * C8 [UNI]   r9  :: C * C9 [UNI]   r10 :: C * C0 [UNI]
r11 :: C * C1 [UNI]   r12 :: C * C2 [UNI]   r13 :: C * C3 [UNI]   r14 :: C * C4 [UNI]   r15 :: C * C5 [UNI]
r16 :: C * C6 [UNI]   r17 :: C * C7 [UNI]   r18 :: C * C8 [UNI]   r19 :: C * C9 [UNI]   r20 :: C * C0 [UNI]
r21 :: C * C1 [UNI]   r22 :: C * C2 [UNI]   r23 :: C * C3 [UNI]   r24 :: C * C4 [UNI]   r25 :: C * C5 [UNI]
r26 :: C * C6 [UNI]   r27 :: C * C7 [UNI]   r28 :: C * C8 [UNI]   r29 :: C * C9 [UNI]   r30 :: C * C0 [UNI]
r31 :: C * C1 [UNI]   r32 :: C * C2 [UNI]   r33 :: C * C3 [UNI]   r34 :: C * C4 [UNI]   r35 :: C * C5 [UNI]
r36 :: C * C6 [UNI]   r37 :: C * C7 [UNI]   r38 :: C * C8 [UNI]   r39 :: C * C9 [UNI]   r40 :: C * C0 [UNI]
r41 :: C * C1 [UNI]   r42 :: C * C2 [UNI]   r43 :: C * C3 [UNI]   r44 :: C * C4 [UNI]   r45 :: C * C5 [UNI]
r46 :: C * C6 [UNI]   r47 :: C * C7 [UNI]   r48 :: C * C8 [UNI]   r49 :: C * C9 [UNI]   r50 :: C * C0 [UNI]
r51 :: C * C1 [UNI]   r52 :: C * C2 [UNI]   r53 :: C * C3 [UNI]   r54 :: C * C4 [UNI]   r55 :: C * C5 [UNI]
r56 :: C * C6 [UNI]   r57 :: C * C7 [UNI]   r58 :: C * C8 [UNI]   r59 :: C * C9 [UNI]   r60 :: C * C0 [UNI]
r61 :: C * C1 [UNI]   r62 :: C * C2 [UNI]   r63 :: C * C3 [UNI]   r64 :: C * C4 [UNI]   r65 :: C * C0 [UNI]

ENDCONTEXT

If I compile it with Ampersand-v3.9.1 [development:b051de7], the database is not created properly. In the ERROR log, I see lines such as:

[2018-02-28 15:06:45] API.ERROR: MYSQL error 1069: Too many keys specified; max 64 keys allowed in query:CREATE INDEX "C_r63" ON "C" ("r63") [] []

As a consequence, applications that have this many (univalent) relations will not run. This currently happens in projects that we do, where we need to create simple/flat forms, and as a consequence, there are many relations that have SRC=Form and TGT=SomeOtherConcept.

A (cumbersome) workaround for this is to remove CREATE INDEX statements from mysql-installer.json, such that for every concept, no more than 63 (or 64) keys are left over. After all, these keys seem to only affect performance.

It would be nice if the generator would not generate more than these 63/64 keys, so that such applications would (continue to) run.